WO2008120497A1 - Heat-resistant magnesium alloy - Google Patents

Heat-resistant magnesium alloy Download PDF

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Publication number
WO2008120497A1
WO2008120497A1 PCT/JP2008/052085 JP2008052085W WO2008120497A1 WO 2008120497 A1 WO2008120497 A1 WO 2008120497A1 JP 2008052085 W JP2008052085 W JP 2008052085W WO 2008120497 A1 WO2008120497 A1 WO 2008120497A1
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WIPO (PCT)
Prior art keywords
magnesium alloy
crystal
heat
grain boundary
mass
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PCT/JP2008/052085
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French (fr)
Japanese (ja)
Inventor
Tsukasa Sugie
Kyoichi Kinoshita
Motoharu Tanizawa
Manabu Miyoshi
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Kabushiki Kaisha Toyota Jidoshokki
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Application filed by Kabushiki Kaisha Toyota Jidoshokki filed Critical Kabushiki Kaisha Toyota Jidoshokki
Priority to EP08710964A priority Critical patent/EP2135965A4/en
Priority to US12/594,508 priority patent/US20100116378A1/en
Priority to JP2009507427A priority patent/JPWO2008120497A1/en
Publication of WO2008120497A1 publication Critical patent/WO2008120497A1/en

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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C23/00—Alloys based on magnesium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C23/00—Alloys based on magnesium
    • C22C23/02—Alloys based on magnesium with aluminium as the next major constituent

Definitions

  • the present invention relates to a heat-resistant magnesium alloy that can withstand use under high temperature and high load.
  • Magnesium alloys which are lighter than aluminum alloys, are being widely used as sailing materials and vehicle materials from the viewpoint of weight reduction.
  • magnesium alloys are not sufficient in strength and heat resistance depending on the application, so further improvement in properties is required.
  • Japanese Laid-Open Patent Publication Nos. 2004-162090 and 2004-232060 disclose magnesium alloys containing appropriate amounts of calcium (Ca) and aluminum (A1).
  • the dislocation motion is stopped because the Ca 1 A 1 compound or Mg—Ca compound is crystallized or precipitated at the grain boundary of the Mg crystal grains of the magnesium alloy.
  • the magnesium alloy exhibits excellent heat resistance with little creep deformation even at high temperatures.
  • the magnesium alloy described above strengthens the magnesium alloy by dissolving Mn in the Mg crystal grains. Disclosure of the invention
  • the metal paper weave of the alloy greatly affects its properties. For this reason, in order to obtain a magnesium alloy with sufficient strength and creep resistance for use at high temperatures, it is necessary to control the metal texture by making the types and amounts of additive elements appropriate.
  • the present invention reinforces both the crystal grains and the grain boundaries, and exhibits excellent heat resistance.
  • the aim is to use a metal alloy.
  • the heat-resistant magnesium alloy of the present invention comprises the main component magnesium ( ⁇ g), one or more first alloy elements M 1 selected from aluminum (A1) and Eckel (N i), manganese ( Mn), barium (B a), chromium (Cr) and iron (Fe) forces, any one or more of the second alloy element M2 selected from the force, calcium (C a), and
  • “microscopically continuous network” has a macroscopic network structure (three-dimensional network structure), and a state in which crystals are continuously present within the network. (See Fig. 2). Therefore, even if it has a network structure, it does not include the discontinuous state (see Fig. 3) that consists of small crystals inside.
  • the heat-resistant magnesium alloy of the present invention will be described in detail later.
  • the second alloy element M 2 plate-like precipitates are formed in the grain of Mg crystal grains, and microscopically continuous in the grain boundaries. It has grain boundary crystals that form a network. Since plate-like precipitates are present in the Mg crystal grains, the movement of dislocations in the Mg crystal grains is hindered and deformation becomes difficult.
  • the grain boundary crystallized material that forms the network is present microscopically continuously at the grain boundary of the Mg crystal grains, so that the grain boundary strength i is improved.
  • the magnesium alloy of the present invention exhibits high mechanical properties even in a high temperature region.
  • the heat-resistant magnesium alloy of the present invention remarkably improves the characteristics at high temperatures by strengthening both the intragranular and O boundaries of Mg crystal grains.
  • the precipitate is preferably composed of a Laves phase compound having a C15 type crystal structure.
  • the precipitate is preferably precipitated in parallel with the ⁇ 001 ⁇ plane of the Mg crystal.
  • the grain boundary crystallized material forming a microscopic continuous network is preferably composed of an Mg-Ml-Ca-based compound.
  • the Fujimi grain boundary crystallized material is composed of a mixed crystal phase of Laves phase compounds having a C 14 type crystal structure and a C 36 type crystal structure.
  • the mixed crystal structure preferably contains more C14-boiling crystal structure than C36 type crystal structure.
  • the grain boundary crystallized substance is composed of a mixed crystal phase of Laves phase compound of C 14 hard crystal structure and C 3 6 type crystal structure, the compound constituting the network is almost single crystal in appearance without phase separation (Fig. 4) and the area of the crystal grain boundary and the number of crystal grains constituting the net ⁇ are minimized.
  • C 14 type “C 15 type” and “C 36 type” are symbols of Strukturberichte clogging, which are Mg Z n 2 and M in the Laves phase, respectively. It represents three similar ⁇ : like crystal structures represented by g C u 2 and MgN i 2 .
  • the entire heat-resistant magnesium alloy of the present invention is 100% by mass
  • Ca is 2% by mass or more and 4% by mass or less
  • the first alloy element Ml is 0.9% by mass ratio (Ml / Ca) to Ca. or 1.1 or less, wherein comprises a second alloying element M2 of 0.3 mass% or more 0.6 mass 0/0 or less, Shi remainder preferable that consists M g and inevitable impurities les.
  • C a is 1.235 atomic% or more and 2.470 atomic% or less
  • the atomic ratio of the first alloy element M 1 to C a (MlZCa ) 1.34 or more and 1.63 or less, preferably 0.13 atomic% or more and 0.27 atomic% or less of the second alloying element M2, and remaining force SMg and inevitable impurities.
  • the content ratio of the first alloy element, the second alloy element and Ca containing the heat-resistant 14-magnesium alloy power of the present invention within an appropriate range, it is desirable from the viewpoint of the mechanical properties at high temperature, and the metal yarn A heat-resistant raw magnesium alloy with cocoons is obtained.
  • Heat resistance in this specification is evaluated by the mechanical properties of magnesium alloys in high-temperature atmospheres (for example, creep properties by stress relaxation tests and axial force retention tests, or high-temperature strength). Is. Brief Description of Drawings
  • Figure 1 is a metallographic photograph of a cross section of the # 01 test piece observed with a metallographic microscope.
  • Figure 2 is a metallographic image of the # 01 observation sample observed with an electron microscope (TEM).
  • TEM electron microscope
  • Figure 3 is a metal paper weave photograph of # C 1 observed by TEM.
  • Fig. 4 shows a scanning field electron microscope (DF-STEM) image of the observation sample # 01.
  • Fig. 5 is a DF-ST EM image of the observation sample of # C1.
  • Figure 6 shows the TEM image and electron diffraction of the observation sample # 01 (incident direction foil 110
  • Figure 7 shows the TEM image and electron diffraction (incident direction foil 111) of the observation sample # 01.
  • Figure 8 shows the TEM image and electron diffraction of the observation sample of # C 1 (incident direction foil 111
  • Fig. 9 is a DF-S TEM image of the observation sample # 01 observed in the Mg crystal grains. Note that # 01 No. # 01 is a symbol for distinguishing magnesium alloys having different compositions in the examples described later. BEST MODE FOR CARRYING OUT THE INVENTION
  • magnesium alloy The best mode for carrying out the heat-resistant magnesium alloy of the present invention (hereinafter abbreviated as “magnesium alloy”) will be described below.
  • the magnesium alloy of the present invention contains magnesium (M g ) as a main component, first alloy element Ml, second alloy element M2, and calcium (Ca), Mg crystal grains, and Mg crystal grains
  • Mg magnesium
  • a metal paper weave comprising: a plate-like precipitate that precipitates within the grains; a grain boundary crystal that crystallizes at a grain boundary of the Mg crystal grains to form a microscopic continuous network;
  • plate-like precipitates exist in the Mg crystal grains. Plate-like precipitates hinder the movement of dislocations in Mg grains. Crystal deformation occurs when dislocations move on the slip plane.
  • the c-plane of hexagonal Mg crystal In other words, it should be a TO-like precipitate on the ⁇ 001 ⁇ face of the Mg crystal.
  • the plate-like precipitate has a thickness of 2 to 20 nm, and the thicker the wrinkles, the better the leakage characteristics.
  • the precipitate is preferably composed of a Laves phase compound having a C15 type crystal structure. This is because the c-plane of the Mg crystal and the ⁇ 111 ⁇ plane of the C15 structure are likely to form a crystallographically stable interface with each other, and it can be predicted that the formation force S of the plate-like precipitate is promoted.
  • the compound constituting the precipitate having such a crystal structure is preferably an Ml—Ca compound and / or an Mg—Ml—Ca compound.
  • the magnesium alloy of the present invention may further have fine particles in the Mg crystal grains.
  • the fine particles are in the Mg crystal grains and mostly around the plate-like precipitates. It is considered that this fine particle does not directly contribute to the improvement of the strength in the Mg crystal grains even in the Mg crystal grains.
  • the fine particles are related to the formation of precipitates (described later), and the fine particles are fine particles containing M2, such as l-M2 compounds.
  • the fine particles are substantially spherical and have a particle size of 10 to 15 nm ⁇ l.
  • the grain boundary crystallized material forming a microscopic continuous network is crystallized and present at the grain boundary of the Mg crystal grain.
  • the grain boundary crystallized crystallizes at the grain boundary of the Mg crystal grains and forms a network.
  • the magnesium alloy containing M2 does not show microscopic continuous I 1 growth in the grain boundary crystals that form the network.
  • the inclusion of M 2 forms a network in which the grain boundary crystallization products are microscopically continuous.
  • the grain boundary crystallized network is 70% or more of the Mg grain boundary that is linearly seen in the cross section of the magnesium alloy region of about 400 ⁇ 600 ⁇ m. It is desirable to cover “coverage”.
  • the grain boundary crystallization is a Laves phase compound of C 14 type crystal structure and C 36 type crystal structure. It may consist of a mixed crystal phase of the product.
  • the C14 type crystal structure and the C36 type crystal structure are desirable because they are hexagonal and easily form a mixed crystal phase. Since the Laves phase compound in the mixed crystal phase is as close to a single crystal as possible, the grain boundary crystallization is microscopically continuous, and the grain boundary area and grain size of the compound composing the network. The number is minimized.
  • the grain boundary crystallization product is preferably composed of a Mg-M1-Ca compound.
  • Mg 2 Ca has a C 14 type crystal structure, and when M 1 is dissolved in Mg 2 Ca, a mixed crystal phase of a C 14 type crystal structure and a C 36 type crystal structure is formed. Guessed. At this time, the mixed crystal phase preferably contains more C14 type crystal structure than C36 type crystal structure.
  • the magnesium alloy of the present invention having the metal paper weave as described above contains the main component of magnesium (Mg), the first alloy element Ml, the second alloy element M2, and calcium (Ca).
  • the first alloy element Ml at least one selected from aluminum (A 1) and nickel (Ni) can be used. Both A1 and Ni react with Ca to form a compound and have a C15-type Laves structure. However, Mg 2 C a, which has a C14-type Laves structure, is dominant. , A 1 and / or Ni dissolve in Mg 2 C a to form a mixed crystal phase of C 14 type Laves structure and C 36 type Laves structure.
  • the second alloy element M 2 at least one selected from manganese (Mn), barium (Ba), chromium (Cr), and iron (Fe) forces can be used.
  • Mn manganese
  • Ba barium
  • Cr chromium
  • Fe iron
  • the second alloy element M 2 needs to react at a higher temperature than the first alloy element M 1 and T 3 and be difficult to dissolve in Mg.
  • the second alloy element at least one selected from manganese (Mn), norlium (Ba), throat (Cr) and iron (F e) force is used among the transition elements. be able to.
  • These elements have the same atomic structure, have similar crystal structures, and form compounds only between Ml and a relatively high temperature region, specifically between T 1 and T 3.
  • the magnesium alloy of the present invention contains at least one kind of the above-mentioned first alloy element and second alloy element.
  • One kind of each of the first element and the second element may be included, or one or both of the forces and the displacement force may be included.
  • the magnesium alloy of the present invention has two masses of Ca when the total is 100% by mass. / 0 or more and 4% by mass or less, and the first alloy element M 1 is 0.9 to 1.1 by mass ratio (M1 / C a) to C a, and the second alloy element M2 is 0.3% by mass or more. It is preferable that the content is 0.6% by mass or less and the balance is Mg and inevitable impurities.
  • the magnesium alloy of the present invention has a Ca content of 1.235 atomic% or more and 2.470 atomic% or less, and the tooth 1st alloy element M 1 is an atom with respect to C a when the total is 10 ° atomic%.
  • the ratio (Ml / Ca) is 1.34 or more and 1.63 or less
  • the second alloy element M 2 is contained in an amount of 0.13 atomic% or more and 0.27 atomic% or less, with the balance being Mg and inevitable impurities. preferable. .
  • & is less than 0.9 by mass (ie, less than 1.34 by atomic ratio)
  • the content of Ca is large and the forgery is considered, which is not preferable.
  • Ml-no-Ca exceeds 1.1 by mass (ie, exceeds 1.63 by atomic ratio)
  • the grain boundary crystallization is unlikely to become a mixed crystal phase, and only C 36 type Laves structure This is preferable because the composed crystal grains are easily formed and phase separation occurs.
  • the C36 crystal structure is exposed to high temperatures. Then, it is easy to make a phase transition to CI 5 type crystal structure (Scripta Material ia 51 (2004) 1005- 1010).
  • the C 15 crystal structure tends to be agglomerated in a high temperature region and does not form a microscopically continuous crystallized network, so that the properties at high temperatures are significantly reduced.
  • a more preferable M 1 / Ca value is 0.95 or more and 1.05 or less (that is, 1.4 2 to 1.5 6 in terms of atomic ratio).
  • the content ratio of the second alloy element M 2 is less than 0.3% by mass (that is, 0.1 3 atom 0 /.), It is possible to add M l constituting the precipitate as a compound in the P process (solidification process). This is not preferable because the precipitate cannot be sufficiently precipitated. In addition, a large amount of M 1 force 2 does not form a crystal, and it does not take a mixed crystal structure as a grain boundary crystallized product. On the other hand, when the content ratio of ⁇ 2 exceeds 0.6 mass% (that is, 0.27 atomic%), the compound containing ⁇ 2 precipitates in the grain boundary crystallized product. Further, the lower limit of the content ratio of ⁇ 2 is 0.34% by mass (that is, 0.15 atomic%) or more. The upper limit is 0.5 5 mass% (ie 0.25 atomic%) or less, and further 0.5 mass% (that is, 0.23 atomic%) or less.
  • C a is an element that forms C 14 and C 36 Laves structures together with Mg. If the Ca content is less than 2% by mass (ie, 1.235% by atom), precipitates and grain boundary crystals are not sufficiently formed, and the effect of improving heat resistance is not sufficient. It ’s not. On the other hand, if the Ca content exceeds 4% by mass (that is, 2.470% by atom), the amount of precipitates and grain boundary crystallized products will increase and cause problems in post-processing. This is not preferable. More preferably, the Ca content is 2.5 mass% or more and 3.5 mass% or less (that is, 1.5 4 atomic% or more and 2. 16 atomic% or less). Not limited to gravity, but it can also be die-cast.
  • ⁇ used for forging does not matter whether it is a sand mold or a mold.
  • the cooling rate in the solidification process is no particular limitation on the cooling rate in the solidification process, but it is preferable to cool in the air.
  • the use of the magnesium alloy of the present invention extends to various fields such as space, military and aviation, as well as automobiles and home electric Saito.
  • the magnesium alloy strength of the present invention can be applied to products that are used in high-temperature environments by taking advantage of its heat resistance, such as engines, transmissions, compressors for air conditioners or related products that are installed in the engine compartment of automobiles. If used, it is more preferable. Specific examples include cylinder heads for internal combustion engines, cylinder plugs, oil pans, turbocharger impellers for internal combustion engines, transmission cases used in automobiles, and the like.
  • Chloride-based flux was applied to the inner surface of an iron crucible preheated in an electric furnace, and weighed pure magnesium ingot, pure Al, and Mg-Mn alloy as required, were dissolved. In addition, weighed Ca was added during this easy, which was maintained at 75 ° C.
  • the molten metal was sufficiently stirred to completely dissolve the raw materials, and then kept calm for a while.
  • a mixed gas of carbon dioxide gas and SF 6 gas was sprayed on the hot metal surface, and flux was appropriately sprayed on the hot metal surface.
  • the various alloy melts thus obtained were poured into a mold having a predetermined shape (a pouring process) and solidified in an atmosphere (solidification process).
  • a 3 O ramX 30 O mmX 4 O ram test piece was manufactured by gravity.
  • the obtained specimens were designated as # 0 1 (Example including Mn) and # C 1 (Comparative example not including Mn). Table 1 shows the chemical composition of each specimen.
  • Specimens # 01 and # C1 were observed with a metal microscope or a transmission electron microscope (TEM). .
  • Figure 1 is a metallographic photograph of a cross section of the # 01 test piece observed with a metallographic microscope.
  • Mg crystal grains (bright parts) and grain boundary crystallized grains (black parts) appearing in a network form at the grain boundaries of Mg crystal grains were observed.
  • a metal paper weaving photograph similar to that in Fig. 1 was obtained by observing the cross section of the specimen # C1. In other words, macroscopically, grain-like crystallized crystals were observed in the specimens of the les and misalignments.
  • each test piece was used as a flaky observation sample and observed using a TEM.
  • Figures 2 and 3 are metal paper weaving photographs of # 01 and # C1 observed with TEM, respectively. In both cases, grain boundaries where two or more primary Mg grains were adjacent to each other were observed. In Fig. 2 (# 01), the grain boundary crystallization (black part) grew like a lamellar and was continuous. In Fig. 3 (# C1), the grain boundary crystals were partially discontinuous and discontinuous. The coverage of # 01 network is about 90%.
  • Figures 4 and 5 are dark-field scanning transmission electron microscope (DF-STEM) images of the observed grain boundary crystals of the # 01 and #C 1 samples, respectively.
  • the specimen of # 01 does not show phase separation as shown in Figure 4, but the specimen of #C 1 Phase separation was observed.
  • elemental mapping by energy dispersive X-ray spectroscopy (EDX) is performed on the DF—ST EM images in Figs. 4 and 5, Mg, A 1 and Ca are uniformly distributed in Fig. 4 (# 01).
  • Fig. 5 (# C1) the concentration of A 1 was higher in the grains that were separated into ⁇ and phase separated. Electron diffraction of the C36 crystal structure was obtained from the crystal grains with high A1 concentration.
  • Fig. 1 elemental mapping by energy dispersive X-ray spectroscopy
  • Figures 6 and 7 are TEM images of specimen # 01 and Figure 8 is specimen # (1, 1.
  • Figure 6 shows the Alt direction 110>
  • Figures 7 and 8 show the incident direction 111> Mg.
  • Fig. 6 '(# 01) streaky precipitates parallel to the ⁇ 001 ⁇ plane were observed, and the incident direction was tilted at the same position as in Fig. 6.
  • the precipitate was a plate with 5 Fff on the ⁇ 001 ⁇ plane, and when STEM-EDX analysis was performed on this plate-like precipitate, mainly A 1 and Ca were detected.
  • an electron diffraction pattern of a C 15 type crystal structure corresponding to A 1 2 Ca was obtained from the plate-like precipitate. It was.
  • Figure 9 is a DF-STEM image of the observed # 01 observation sample in the Mg crystal grains. A plurality of fine particles were observed around the plate-like precipitate. When elemental analysis was performed on fine particles (B in Fig. 9), Mn was detected. Even when the plate-like precipitate was analyzed (A in Fig. 9), Mn was not detected.
  • Specimens # 01 and # (shown in Table 1): AXE662, A E42, and AZ91D (all AS TM standards) shown in Table 2 were subjected to stress relaxation tests.
  • the heat resistance (creep characteristics) of the magnesium alloy was investigated
  • the stress relaxation test measures the process in which the stress when a load is applied to a specified amount of deformation during the test time decreases with time. Specifically, in an air atmosphere at 150 ° C, a compressive stress of 10 OMPa was applied to the specimen, and the displacement of the specimen at that time was kept constant along with the passage of time.
  • Table 2 and Table 3 show the alloy composition of each specimen and the stress after 40 hours of the stress relaxation test, with the magnesium alloy compositions in Table 2 and Table 3. The balance is Mg, and “RE” is Misch Metal.
  • Specimen # 01 showed a particularly low rate of decrease in applied stress compared to other specimens, and exhibited high creep resistance even at high temperatures. This is because, due to the presence of Mn, a strong microscopically continuous network was formed at the grain boundary of the Mg crystal grains, and the dislocation movement was suppressed by the plate-like precipitates in the Mg crystal grains. This is because the deformation resistance increased and the strength of specimen # 01 improved.

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Abstract

A heat-resistant magnesium alloy comprising Mg as a main component; at least any one selected from among Al and Ni as a first alloy element (M1); at least any one selected from among Mn, Ba, Cr and Fe as a second alloy element (M2); and Ca. This heat-resistant magnesium alloy has a metallographic structure containing Mg crystal grains; platelike precipitates having precipitated within the Mg crystal grains; and grain boundary crystallizates having crystallized at boundaries of the Mg crystal grains and forming a microscopically continuous network. By virtue of the presence of the platelike precipitates within the Mg crystal grains, the transfer of dislocation within the Mg crystal grains is blocked to thereby restrict any deformation. Further, by virtue of the microscopically continuous presence of network forming grain boundary crystallizates at boundaries of the Mg crystal grains, the grain boundary strength is enhanced. This magnesium alloy having its Mg crystal grain interiors and boundaries simultaneously strengthened retains high mechanical properties even in high temperature region.

Description

明細書 耐熱性マグネシゥム合金 技術分野  Specification Heat Resistant Magnesium Alloy Technical Field
本発明は、 高温のもと高負荷での使用に耐えうる耐熱性マグネシウム合金に関 するものである。 技賺景  The present invention relates to a heat-resistant magnesium alloy that can withstand use under high temperature and high load. Technical scene
アルミニウム合金よりさらに軽量なマグネシウム合金は、 軽量化の観点から航 ^^才料や車両材料などとして広く用いられつつある。 しかしながら、 マグネシ ゥム合金は、 用途によっては強度や耐熱生が充分ではないため、 さらなる特性の 向上が求められている。  Magnesium alloys, which are lighter than aluminum alloys, are being widely used as sailing materials and vehicle materials from the viewpoint of weight reduction. However, magnesium alloys are not sufficient in strength and heat resistance depending on the application, so further improvement in properties is required.
そこで、 特開 2004— 162090号公報および特開 2004— 23206 0号公報には、 カルシウム （Ca) およびアルミニウム （A1) を適量含有させ たマグネシウム合金が開示されている。 これらの文献では、 マグネシウム合金の Mg結晶粒の粒界に C a一 A 1化合物や Mg— C a化合物が晶出または析出する ため、 転位の運動が食い止められる。 その結果、 マグネシウム合金は、 高温域で もクリープ変形が少なく、 優れた耐熱 を示す。 さらに、 上記のマグネシウム合 金は、 Mnを Mg結晶粒中に固溶させることで、 マグネシウム合金を固溶強化さ せている。 発明の開示  In view of this, Japanese Laid-Open Patent Publication Nos. 2004-162090 and 2004-232060 disclose magnesium alloys containing appropriate amounts of calcium (Ca) and aluminum (A1). In these documents, the dislocation motion is stopped because the Ca 1 A 1 compound or Mg—Ca compound is crystallized or precipitated at the grain boundary of the Mg crystal grains of the magnesium alloy. As a result, the magnesium alloy exhibits excellent heat resistance with little creep deformation even at high temperatures. Further, the magnesium alloy described above strengthens the magnesium alloy by dissolving Mn in the Mg crystal grains. Disclosure of the invention
合金の金属紙織は、 その特性に大きく影響する。 そのため、 高温での使用に十 分な強度ゃ耐クリープ性を有するマグネシウム合金を得るためには、 添加元素の 種類や量などを適切なものとし、 金属 織を制御する必要がある。  The metal paper weave of the alloy greatly affects its properties. For this reason, in order to obtain a magnesium alloy with sufficient strength and creep resistance for use at high temperatures, it is necessary to control the metal texture by making the types and amounts of additive elements appropriate.
本発明は、 適切な合金元素を用いマグネシウム合金の金属紙織を制御すること で、 結晶粒內およひ 晶粒界がともに強化され、 優れた耐熱生を示すマグネシゥ ム合金を樹共することを目 0勺とする。 By controlling the metal paper weave of a magnesium alloy using an appropriate alloy element, the present invention reinforces both the crystal grains and the grain boundaries, and exhibits excellent heat resistance. The aim is to use a metal alloy.
すなわち、 本発明の耐熱性マグネシウム合金は、 主成分のマグネシウム （Μ g) と、 アルミニウム （A1) およびエッケル (N i) から選ばれるいずれ力一 種以上の第一合金元素 M 1と、 マンガン (Mn) 、 バリウム (B a) 、 クロム (Cr) および鉄 (Fe) 力、ら選ばれるいずれ力一種以上の第二合金元素 M2と、 カルシウム (C a) と、 を含み、  That is, the heat-resistant magnesium alloy of the present invention comprises the main component magnesium (Μ g), one or more first alloy elements M 1 selected from aluminum (A1) and Eckel (N i), manganese ( Mn), barium (B a), chromium (Cr) and iron (Fe) forces, any one or more of the second alloy element M2 selected from the force, calcium (C a), and
Mg結晶粒と、 該 Mg結晶粒の粒内に析出する板状の析出物と、 該 Mg結晶 粒の粒界に晶出して微視的に連続するネットワークを形成する粒界晶出物と、 を 含む金属紙織を有することを特徴とする。  An Mg crystal grain, a plate-like precipitate that precipitates in the Mg crystal grain, and a grain boundary crystallized crystal that crystallizes at the grain boundary of the Mg crystal grain to form a microscopic continuous network; It has a metal paper weave containing.
なお、 本明細書において 「微視的に連続するネットワーク」 とは、 巨視的には ネットワーク構造 （三次元網目構造） をとり、 ネットワークの内部においても結 晶カ S連続して存在している状態 （図 2参照） である。 したがって、 ネットワーク 構造をとつていてもその内部が小さな結晶で構成されている不連続な状態 （図 3 参照） は、 含まない。  In the present specification, “microscopically continuous network” has a macroscopic network structure (three-dimensional network structure), and a state in which crystals are continuously present within the network. (See Fig. 2). Therefore, even if it has a network structure, it does not include the discontinuous state (see Fig. 3) that consists of small crystals inside.
本発明の耐熱性マグネシウム合金は、 後に詳説するが、 第二合金元素 M 2を含 むことで、 Mg結晶粒の粒內には板状の析出物、 粒界には微視的に連続するネッ トワークを形成する粒界晶出物を有する。 板状の析出物が M g結晶粒内に存在す るため、 Mg結晶粒内での転位の移動が妨げられ、 変形しにくくなる。 また、 ネ ットワークを形成する粒界晶出物が Mg結晶粒の粒界に微視的に連続して存在す るため、 粒界の強 i が向上する。 その結果、 本発明のマグネシウム合金は、 高温 領域においても高い機械特性を示す。つまり、 本発明の耐熱性マグネシウム合金 は、 Mg結晶粒の粒内およ O立界をともに強化することで、 高温領域での觀的 特性が大きく向上する。  The heat-resistant magnesium alloy of the present invention will be described in detail later. By containing the second alloy element M 2, plate-like precipitates are formed in the grain of Mg crystal grains, and microscopically continuous in the grain boundaries. It has grain boundary crystals that form a network. Since plate-like precipitates are present in the Mg crystal grains, the movement of dislocations in the Mg crystal grains is hindered and deformation becomes difficult. In addition, the grain boundary crystallized material that forms the network is present microscopically continuously at the grain boundary of the Mg crystal grains, so that the grain boundary strength i is improved. As a result, the magnesium alloy of the present invention exhibits high mechanical properties even in a high temperature region. In other words, the heat-resistant magnesium alloy of the present invention remarkably improves the characteristics at high temperatures by strengthening both the intragranular and O boundaries of Mg crystal grains.
前記析出物は、 C15型結晶構造のラーべス相化合物からなるのが望ましい。 また、 前記析出物は、 Mg結晶の {001} 面に平行に析出するのが望ましい。 微視的に連続するネットワークを形成する歸己粒界晶出物は、 Mg-Ml-C a系化合物からなるのが望ましい。 また、 藤己粒界晶出物は、 C 14型結晶構造 と C 36型結晶構造のラーべス相化合物の混晶相からなるのが望ましく、 このと き、 前記混晶構造は、 C 36型結晶構造よりも C 14騰晶構造を多く含むとよ い。 The precipitate is preferably composed of a Laves phase compound having a C15 type crystal structure. The precipitate is preferably precipitated in parallel with the {001} plane of the Mg crystal. The grain boundary crystallized material forming a microscopic continuous network is preferably composed of an Mg-Ml-Ca-based compound. In addition, it is desirable that the Fujimi grain boundary crystallized material is composed of a mixed crystal phase of Laves phase compounds having a C 14 type crystal structure and a C 36 type crystal structure. In addition, the mixed crystal structure preferably contains more C14-boiling crystal structure than C36 type crystal structure.
析出物が、 Mg結晶の {001}面に平行に析出すると、 六方晶 Mg結晶のす ベり面上での転位の移動が抑制される。 粒界晶出物が、 C 14難晶構造と C 3 6型結晶構造のラーべス相化合物の混晶相からなると、 ネットワークを構成する 化合物は相分離することなく見た目にほぼ単結晶 （図 4参照） になり、 ネットヮ →を構成する結晶粒界の面積や結晶粒の数が最小となる。  When precipitates precipitate in parallel to the {001} plane of Mg crystals, the movement of dislocations on the slip plane of hexagonal Mg crystals is suppressed. When the grain boundary crystallized substance is composed of a mixed crystal phase of Laves phase compound of C 14 hard crystal structure and C 3 6 type crystal structure, the compound constituting the network is almost single crystal in appearance without phase separation (Fig. 4) and the area of the crystal grain boundary and the number of crystal grains constituting the net ヮ are minimized.
なお、 上記の 「C 1 4型」 、 「C 1 5型」 、 「C 3 6型」 とは、 Strukturberichte詰の記号であって、 それぞれ、 ラーべス相のうちの Mg Z n 2、 M g C u 2、 MgN i 2で代表される 3つの類似した^:的な結晶構造を表す。 The above “C 14 type”, “C 15 type” and “C 36 type” are symbols of Strukturberichte clogging, which are Mg Z n 2 and M in the Laves phase, respectively. It represents three similar ^: like crystal structures represented by g C u 2 and MgN i 2 .
さらに、 前記 M g結晶粒内に前記第二合金元素 M 2を含む微粒子を有するのが 望ましい。  Furthermore, it is desirable to have fine particles containing the second alloy element M 2 in the Mg crystal grains.
本発明の耐熱性マグネシゥム合金全体を 100質量％としたときに、 C aを 2 質量％以上 4質量％以下、 前記第一合金元素 Mlを C aに対する質量比 (Ml/ Ca) で 0. 9以上 1. 1以下、 前記第二合金元素 M2を 0. 3質量％以上 0. 6質量0 /0以下含み、 残部が M gおよび不可避不純物からなるのが好ましレ、。 When the entire heat-resistant magnesium alloy of the present invention is 100% by mass, Ca is 2% by mass or more and 4% by mass or less, and the first alloy element Ml is 0.9% by mass ratio (Ml / Ca) to Ca. or 1.1 or less, wherein comprises a second alloying element M2 of 0.3 mass% or more 0.6 mass 0/0 or less, Shi remainder preferable that consists M g and inevitable impurities les.
あるいは、 本発明の耐熱性マグネシウム合金全体を 100原子％としたときに、 C aを 1. 235原子％以上 2. 470原子％以下、 前記第一合金元素 M 1を C aに対する原子比 （MlZCa) で 1. 34以上1. 63以下、 前記第二合金元 素 M2を 0. 13原子％以上 0. 27原子％以下含み、 残部力 SMgおよび不可避 不純物からなるのが好ましレ、。  Alternatively, when the total heat-resistant magnesium alloy of the present invention is 100 atomic%, C a is 1.235 atomic% or more and 2.470 atomic% or less, and the atomic ratio of the first alloy element M 1 to C a (MlZCa ) 1.34 or more and 1.63 or less, preferably 0.13 atomic% or more and 0.27 atomic% or less of the second alloying element M2, and remaining force SMg and inevitable impurities.
本発明の耐熱 14マグネシゥム合金力含有する第一合金元素、 第二合金元素およ ぴ C aの含有割合を適切な範囲とすることで、 高温での機械特性の点から望まし レ、金属糸纖をもつ耐熱生マグネシゥム合金が得られる。  By making the content ratio of the first alloy element, the second alloy element and Ca containing the heat-resistant 14-magnesium alloy power of the present invention within an appropriate range, it is desirable from the viewpoint of the mechanical properties at high temperature, and the metal yarn A heat-resistant raw magnesium alloy with cocoons is obtained.
なお、 本明細書でいう 「耐熱 [■生」 は、 高温雰囲気中におけるマグネシウム合金 の機械的性質 （だとえば、 応力緩和試験や軸力保持試験によるクリープ特性また は高温強度など） で評価されるものである。 図面の簡単な説明 “Heat resistance” in this specification is evaluated by the mechanical properties of magnesium alloys in high-temperature atmospheres (for example, creep properties by stress relaxation tests and axial force retention tests, or high-temperature strength). Is. Brief Description of Drawings
図 1は、 #01の試験片の断面を金属顕微鏡で観察した金属組織写真である。 図 2は、 # 01の観察試料を 電子顕微鏡 (TEM) で観察した金属組織写 真である。  Figure 1 is a metallographic photograph of a cross section of the # 01 test piece observed with a metallographic microscope. Figure 2 is a metallographic image of the # 01 observation sample observed with an electron microscope (TEM).
図 3は、 # C 1の観察試料を TEMで観察した金属紙織写真である。  Figure 3 is a metal paper weave photograph of # C 1 observed by TEM.
図 4は、 # 01の観察試料の喑視野走査透過電子顕微鏡 （DF— STEM) 像 である。  Fig. 4 shows a scanning field electron microscope (DF-STEM) image of the observation sample # 01.
図 5は、 # C 1の観察試料の D F-ST EM像である。  Fig. 5 is a DF-ST EM image of the observation sample of # C1.
図 6は、 #01の観察試料の TEM像および電子回折 （入射方向はく 110 Figure 6 shows the TEM image and electron diffraction of the observation sample # 01 (incident direction foil 110
» である。 »
図 7は、 #01の観察試料の TEM像および電子回折 （入射方向はく 111 Figure 7 shows the TEM image and electron diffraction (incident direction foil 111) of the observation sample # 01.
» である。 »
図 8は、 # C 1の観察試料の T EM像および電子回折 （入射方向はく 111 Figure 8 shows the TEM image and electron diffraction of the observation sample of # C 1 (incident direction foil 111
» である。 »
図 9は、 #01の観察試料の M g結晶粒内を観察した D F-S T EM像である。 なお、 #01ぉょぴ#〇1は、 後述の実施例において、 組成の異なるマグネシ ゥム合金を区別するための記号である。 発明を実施するための最良の形態  Fig. 9 is a DF-S TEM image of the observation sample # 01 observed in the Mg crystal grains. Note that # 01 No. # 01 is a symbol for distinguishing magnesium alloys having different compositions in the examples described later. BEST MODE FOR CARRYING OUT THE INVENTION
以下に、 本発明の耐熱性マグネシウム合金 （以下 「マグネシウム合金」 と略 記） を実施するための最良の形態を説明する。  The best mode for carrying out the heat-resistant magnesium alloy of the present invention (hereinafter abbreviated as “magnesium alloy”) will be described below.
本発明のマグネシウム合金は、 主成分のマグネシウム （Mg) と、 第一合金元 素 Mlと、 第二合金元素 M2と、 カルシウム （Ca) と、 を含み、 Mg結晶粒と、 M g結晶粒の粒内に析出する板状の析出物と、 M g結晶粒の粒界に晶出して微視 的に連続するネットワークを形成する粒界晶出物と、 を含む金属紙織を有する。 本発明のマグネシウム合金では、 板状の析出物が Mg結晶粒内に存在する。 板 状の析出物は、 Mg結晶粒内での転位の移動を妨げる。 結晶の変形は、転位がす ベり面上を移動することにより生じる。 したがって、 六方晶 Mg結晶の c面すな わち Mg結晶の {001} 面に TOな板状析出物であるとよい。 なお、 板状析出 物は、 その板厚が 2〜20nmになり、 娜が厚いほど漏的特性が向上する。 また、 析出物は、 C15型結晶構造のラーべス相化合物からなるとよい。 Mg 結晶の c面と C15構造の {111} 面とは、 結晶学的に互いに安定な界面を形 成しやすく、 板状析出物の形成力 S促進されると予測できるからである。 このよう な結晶構造を有する析出物を構成する化合物は、 Ml— C a系化合物および/ま たは Mg— Ml— C a系ィ匕合物であるのがよい。 The magnesium alloy of the present invention contains magnesium (M g ) as a main component, first alloy element Ml, second alloy element M2, and calcium (Ca), Mg crystal grains, and Mg crystal grains A metal paper weave comprising: a plate-like precipitate that precipitates within the grains; a grain boundary crystal that crystallizes at a grain boundary of the Mg crystal grains to form a microscopic continuous network; In the magnesium alloy of the present invention, plate-like precipitates exist in the Mg crystal grains. Plate-like precipitates hinder the movement of dislocations in Mg grains. Crystal deformation occurs when dislocations move on the slip plane. Therefore, the c-plane of hexagonal Mg crystal In other words, it should be a TO-like precipitate on the {001} face of the Mg crystal. The plate-like precipitate has a thickness of 2 to 20 nm, and the thicker the wrinkles, the better the leakage characteristics. The precipitate is preferably composed of a Laves phase compound having a C15 type crystal structure. This is because the c-plane of the Mg crystal and the {111} plane of the C15 structure are likely to form a crystallographically stable interface with each other, and it can be predicted that the formation force S of the plate-like precipitate is promoted. The compound constituting the precipitate having such a crystal structure is preferably an Ml—Ca compound and / or an Mg—Ml—Ca compound.
本発明のマグネシウム合金は、 さらに、 Mg結晶粒の粒内に微粒子を有しても よレヽ。 微粒子は、 Mg結晶粒内であって、 ほとんどが板状析出物の周囲に す る。 この微立子は、 Mg結晶粒内に しても Mg結晶粒内の強度の向上には直 接寄与するものではなレヽと考えられる。 ところが、 ^微丰立子の は析出物の生成 に関係があり (後述) 、 微粒子は、 たとえば l— M2系化合物のような M2を 含む微粒子である。 なお、 微粒子は、 略球形であって粒径が 10〜15 nm禾 l である。  The magnesium alloy of the present invention may further have fine particles in the Mg crystal grains. The fine particles are in the Mg crystal grains and mostly around the plate-like precipitates. It is considered that this fine particle does not directly contribute to the improvement of the strength in the Mg crystal grains even in the Mg crystal grains. However, the fine particles are related to the formation of precipitates (described later), and the fine particles are fine particles containing M2, such as l-M2 compounds. The fine particles are substantially spherical and have a particle size of 10 to 15 nm 禾 l.
本発明のマグネシゥム合金では、 微視的に連続するネットワークを形成する粒 界晶出物が Mg結晶粒の粒界に晶出して存在する。 たとえば、 本発明のマグネシ ゥム合金から第二合金元素 M2を除いた組成であっても、 巨視的には、 粒界晶出 物が M g結晶粒の粒界に晶出するとともにネットワークを形成することがある。 しかしながら、 M2を含まなレ、マグネシゥム合金では、 ネットヮークを形成する 粒界晶出物に、 微視的な連続 I1生が見られないことがわかっている。 一方、 本発明 のマグネシウム合金では、 M 2を含むことにより、 粒界晶出物が、 微視的に連続 するネットワークを形成する。 ネットワークが微視的に連続することで、 ネット ワークを構成する化合物の結晶粒界の面積や結晶粒数が大きく «される。 その 結果、 粒界の強度が向上し、 強化される。 このとき、 粒界晶出物のネットワーク は、 マグネシウム合金の 400 μιηΧ 6 00 μ m程度の領域の断面に線状にみ られる M g結晶粒粒界のうち 70 %以上 （この値を 「ネットワークの被覆率」 と 略記） を被覆しているのが望ましい。 In the magnesium alloy of the present invention, the grain boundary crystallized material forming a microscopic continuous network is crystallized and present at the grain boundary of the Mg crystal grain. For example, even if the composition of the present invention is obtained by removing the second alloy element M2 from the magnesium alloy, the grain boundary crystallized crystallizes at the grain boundary of the Mg crystal grains and forms a network. There are things to do. However, it is known that the magnesium alloy containing M2 does not show microscopic continuous I 1 growth in the grain boundary crystals that form the network. On the other hand, in the magnesium alloy of the present invention, the inclusion of M 2 forms a network in which the grain boundary crystallization products are microscopically continuous. When the network is microscopically continuous, the area of crystal grain boundaries and the number of crystal grains of the compounds constituting the network are increased. As a result, the grain boundary strength is improved and strengthened. At this time, the grain boundary crystallized network is 70% or more of the Mg grain boundary that is linearly seen in the cross section of the magnesium alloy region of about 400 μιηΧ 600 μm. It is desirable to cover “coverage”.
また、 粒界晶出物は、 C 14型結晶構造と C 36型結晶構造のラーべス相化合 物の混晶相からなるとよい。 C 14型結晶構造と C 36型結晶構造とは、 互いに 六方晶系であり、 混晶相を形成し易いため望ましい。 混晶相のラーべス相化合物 は限りなく単結晶に近くなるため、 粒界晶出物は微視的に連続的であって、 ネッ トワークを構成する化合物の結晶粒界の面積や結晶粒数が最小となる。 In addition, the grain boundary crystallization is a Laves phase compound of C 14 type crystal structure and C 36 type crystal structure. It may consist of a mixed crystal phase of the product. The C14 type crystal structure and the C36 type crystal structure are desirable because they are hexagonal and easily form a mixed crystal phase. Since the Laves phase compound in the mixed crystal phase is as close to a single crystal as possible, the grain boundary crystallization is microscopically continuous, and the grain boundary area and grain size of the compound composing the network. The number is minimized.
また、 粒界晶出物は、 M g— M 1— C a系化合物からなるのが望ましい。 M g 2 C aは、 C 14型結晶構造であり、 M g 2 C aに M 1が固溶することで C 14 型結晶構造と C 36型結晶構造との混晶相が形成されると推測される。 このとき、 混晶相は、 C 36型結晶構造よりも C 14型結晶構造を多く含むとよい。 The grain boundary crystallization product is preferably composed of a Mg-M1-Ca compound. Mg 2 Ca has a C 14 type crystal structure, and when M 1 is dissolved in Mg 2 Ca, a mixed crystal phase of a C 14 type crystal structure and a C 36 type crystal structure is formed. Guessed. At this time, the mixed crystal phase preferably contains more C14 type crystal structure than C36 type crystal structure.
以上のような金属紙織を有する本発明のマグネシウム合金は、 主成分のマグネ シゥム （Mg) と、 第一合金元素 Mlと、 第二合金元素 M2と、 カルシウム （C a) と、 を含む。  The magnesium alloy of the present invention having the metal paper weave as described above contains the main component of magnesium (Mg), the first alloy element Ml, the second alloy element M2, and calcium (Ca).
第一合金元素 Mlは、 アルミニウム (A 1) およびニッケル (N i) から選ば れる少なくとも一種を用いることができる。 A1も N iも、 Caと反応して化合 物を形成し、 C15型ラーべス構造をとる元素であるが、 C 14型ラーべス構造 をとる M g 2 C aが支配的な条件では、 A 1および/または N iが M g 2 C a中 に固溶することで、 C 14型ラーべス構造と C 36型ラーべス構造の混晶相が形 成される。 As the first alloy element Ml, at least one selected from aluminum (A 1) and nickel (Ni) can be used. Both A1 and Ni react with Ca to form a compound and have a C15-type Laves structure. However, Mg 2 C a, which has a C14-type Laves structure, is dominant. , A 1 and / or Ni dissolve in Mg 2 C a to form a mixed crystal phase of C 14 type Laves structure and C 36 type Laves structure.
第二合金元素 M 2は、 マンガン （Mn) 、 バリゥム (B a) 、 クロム (Cr) および鉄 (Fe) 力 選ばれる少なくとも一種を用いることができる。 M2とし てこれらの元素を用いることができる理由は、 本発明のマグネシウム合金の ί^¾Ρ 過程での繊変化により説明できる。  As the second alloy element M 2, at least one selected from manganese (Mn), barium (Ba), chromium (Cr), and iron (Fe) forces can be used. The reason why these elements can be used as M2 can be explained by the change in fiber in the process of the magnesium alloy of the present invention.
本発明のマグネシゥム合金からなる鐃物を «する際の一般的な凝固工程 （空 冷） における Ρ曲線から、 3つの ¾停滞点 （それぞれの を Tl、 Τ2お ょぴ Τ3とし、 Τ1>Τ3、 Τ2>Τ3である） が表れることがわかった。 †新易 の温度が初晶温度 （凝固が開合する温度： T 1 = 600°C以上 620°C以下） に ると、 初晶 Mgが晶出する。 また、 T2にきると、 Mlと M2とが反応し て高温生成化合物である Ml—M2系化合物の微粒子が生成されることが予測さ れる。 次に、 共晶 丁3に針ると、 共晶 Mgとともにネットワークを形成す る粒界晶出物が晶出する。 ところが、 ,の微粒子の元素分析を行った結果、 理 論値よりも多くの M2が含まれることがわかった。 すなわち、 T3よりもさらに 低温域において、 微粒子 （Ml—M2系化合物） 力 ^Mlがはき出され、 はき出 された Mlは、 Mg結晶粒内に溶解する C aの纏にともない C aと化合物を形 成して析出することが予測できる。 From the curve in the general solidification process (air-cooling) of the ceramic alloy of the present invention, three ¾ stagnation points (each of which are Tl, Τ2 and ぴ 3, Τ1> Τ3, (Τ2> Τ3). † When the temperature of Shinyaku becomes the primary crystal temperature (temperature at which solidification opens): T 1 = 600 ° C or more and 620 ° C or less, primary Mg is crystallized. In addition, when it comes to T2, it is predicted that Ml and M2 react to produce fine particles of Ml-M2 compound, which is a high temperature compound. Next, when eutectic Ding 3 is reached, a network is formed with eutectic Mg. Grain boundary crystallization occurs. However, as a result of elemental analysis of, fine particles, it was found that more M2 was contained than the theoretical value. That is, in a temperature lower than T3, fine particles (Ml-M2 compound) force ^ Ml is expelled, and the expelled Ml is a combination of Ca and compound dissolved in Mg crystal grains. It can be predicted that this will form and precipitate.
したがって、 第二合金元素 M 2は、 第一合金元素 M 1と T 3より高温で反応す るとともに、 Mgに溶けにくいことが必要である。 このような理由から、 第二合 金元素としては、 遷移元素のなかでもマンガン （Mn) 、 ノ リウム （Ba) 、 ク 口 (Cr) および鉄 （F e) 力、ら選ばれる少なくとも一種を用いることができ る。 これらの元素は、 同禾 の原子判圣をもち、 類似する結晶構造をとり、 さら に Mlと比較的高温領域、 具体的には T 1と T 3との間でのみ化合物を生成する。 なお、 本発明のマグネシウム合金は、 上記の第一合金元素および第二合金元素 をそれぞ l/少なくとも 1種類含む。 第 1元素と第 2元素とがそれぞれ一種類ずつ 含まれていてもよいし、 レ、ずれ力一方または両方力 S複娄 重類含まれてレ、てもよい。 本発明のマグネシゥム合金は、 全体を 100質量％としたときに、 Caを 2質 量。 /0以上 4質量％以下、 前記第一合金元素 M 1を C aに対する質量比 (M1/C a) で 0. 9以上 1. 1以下、 前記第二合金元素 M2を 0. 3質量％以上 0. 6 質量％以下含み、 残部が Mgおよび不可避不純物からなるのが好ましい。 あるい は、 本発明のマグネシゥム合金は、 全体を 10◦原子％としたときに、 Caを 1. 235原子％以上 2. 470原子％以下、 歯己第一合金元素 M 1を C aに対する 原子比 （Ml/Ca) で 1. 34以上1. 63以下、 前記第二合金元素 M 2を 0. 13原子％以上 0. .27原子％以下含み、 残部が Mgおよび不可避不純物からな るのが好ましい。 . Therefore, the second alloy element M 2 needs to react at a higher temperature than the first alloy element M 1 and T 3 and be difficult to dissolve in Mg. For this reason, as the second alloy element, at least one selected from manganese (Mn), norlium (Ba), throat (Cr) and iron (F e) force is used among the transition elements. be able to. These elements have the same atomic structure, have similar crystal structures, and form compounds only between Ml and a relatively high temperature region, specifically between T 1 and T 3. The magnesium alloy of the present invention contains at least one kind of the above-mentioned first alloy element and second alloy element. One kind of each of the first element and the second element may be included, or one or both of the forces and the displacement force may be included. The magnesium alloy of the present invention has two masses of Ca when the total is 100% by mass. / 0 or more and 4% by mass or less, and the first alloy element M 1 is 0.9 to 1.1 by mass ratio (M1 / C a) to C a, and the second alloy element M2 is 0.3% by mass or more. It is preferable that the content is 0.6% by mass or less and the balance is Mg and inevitable impurities. Alternatively, the magnesium alloy of the present invention has a Ca content of 1.235 atomic% or more and 2.470 atomic% or less, and the tooth 1st alloy element M 1 is an atom with respect to C a when the total is 10 ° atomic%. The ratio (Ml / Ca) is 1.34 or more and 1.63 or less, the second alloy element M 2 is contained in an amount of 0.13 atomic% or more and 0.27 atomic% or less, with the balance being Mg and inevitable impurities. preferable. .
]^1/。&が質量比で0. 9未満 （すなわち原子比で 1. 34未満） では、 C aの含有量が多く錶造性が観匕するため好ましくない。 一方、 Mlノ C aが質量 比で 1. 1を超える （すなわち原子比で 1. 63を超える） と、 粒界晶出物が混 晶相になりにくく、 C 36型ラーべス構造のみで構成される結晶粒が形成され易 く、 相分离 るため好ましくなレ、。 さらに、 C 36型結晶構造は、 高温に曝され ると C I 5型結晶構造へと相転移しやすい （Scripta Material ia 51 (2004) 1005- 1010) 。 C 1 5 锆晶構造は、 高温領域で塊状 «しやすく、 微視的に連続する 晶出物ネットワークを形成しないので、 高温における 特性が著しく低下する。 さらに好ましい M 1 /C a値は、 0. 9 5以上 1 . 0 5以下 （すなわち原子比で 1 . 4 2〜1 . 5 6 ) である。 ] ^ 1 /. If & is less than 0.9 by mass (ie, less than 1.34 by atomic ratio), the content of Ca is large and the forgery is considered, which is not preferable. On the other hand, when Ml-no-Ca exceeds 1.1 by mass (ie, exceeds 1.63 by atomic ratio), the grain boundary crystallization is unlikely to become a mixed crystal phase, and only C 36 type Laves structure This is preferable because the composed crystal grains are easily formed and phase separation occurs. In addition, the C36 crystal structure is exposed to high temperatures. Then, it is easy to make a phase transition to CI 5 type crystal structure (Scripta Material ia 51 (2004) 1005- 1010). The C 15 crystal structure tends to be agglomerated in a high temperature region and does not form a microscopically continuous crystallized network, so that the properties at high temperatures are significantly reduced. A more preferable M 1 / Ca value is 0.95 or more and 1.05 or less (that is, 1.4 2 to 1.5 6 in terms of atomic ratio).
第二合金元素 M 2の含有割合が 0. 3質量％ (すなわち 0. 1 3原子0 /。） 未満 では、 P過程 （凝固工程） において析出物を構成する M lを化合物として麟 することができず、 析出物が十分に析出しないため好ましくない。 また、 多くの M 1力 2と結^:ずに残留することで、 粒界晶出物として混晶構造をとらない C 3 6型ラーべス構造のみをもつ結晶粒が形成され易く相分离 ϋ "るため好ましく ない。 一方、 Μ 2の含有割合が 0. 6質量％ (すなわち 0. 2 7原子％) を超え ると、 Μ 2を含有する化合物が粒界晶出物中に析出し、 ネットワークを分断する ことがあるため、 好ましくない。 さらに好ましい Μ 2の含有割合の下限は、 0. 3 4質量％ (すなわち 0. 1 5原子％) 以上である。 さらに好ましレ、Μ 2の上限 は、 0. 5 5質量％ (すなわち 0. 2 5原子％) 以下さらには 0. 5質量％ (す なわち 0. 2 3原子％) 以下である。 If the content ratio of the second alloy element M 2 is less than 0.3% by mass (that is, 0.1 3 atom 0 /.), It is possible to add M l constituting the precipitate as a compound in the P process (solidification process). This is not preferable because the precipitate cannot be sufficiently precipitated. In addition, a large amount of M 1 force 2 does not form a crystal, and it does not take a mixed crystal structure as a grain boundary crystallized product. On the other hand, when the content ratio of Μ2 exceeds 0.6 mass% (that is, 0.27 atomic%), the compound containing Μ2 precipitates in the grain boundary crystallized product. Further, the lower limit of the content ratio of Μ 2 is 0.34% by mass (that is, 0.15 atomic%) or more. The upper limit is 0.5 5 mass% (ie 0.25 atomic%) or less, and further 0.5 mass% (that is, 0.23 atomic%) or less.
C aは、 M gとと.もに C 1 4および C 3 6型ラーべス構造を形成する元素であ る。 C aの含有割合が 2質量％ (すなわち 1 . 2 3 5原子％) 未満では、 析出物 や粒界晶出物が十分に生成されず、 耐熱特性の向上効果が十分ではないため、 好 ましくない。 一方、 C aの含有割合が 4質量％ (すなわち 2. 4 7 0原子％) を 超えると、 析出物や粒界晶出物の生成量が多くなりすぎて、 後加工で問題を生じ ることがあるため好ましくない。 さらに好ましい C aの含有割合は、 2. 5質量 %以上 3 . 5質量％以下 （すなゎち1 . 5 4原子％以上 2. 1 6原子％以下） で 本発明のマグネシウム合金は、 通常の重力錶 加圧^ に限らず、 ダイカス ト錶造したものでもよレ、。 また、 鎳造に使用される βも砂型、 金型等を問わな い。 凝固工程における冷却速度にも特に限定はないが、 大気雰囲気中で放冷する のがよい。 本発明のマグネシウム合金の用途は、 宇宙、 軍事、 航空の分野を初めとして、 自動車、 家庭電键藤等、 各種分野に及ぶ。 もっとも、 その耐熱 を生かして、 高温環境下で使用される製品、 たとえば、 自動車のエンジンルーム内に配置され るエンジン、 トランスミッション、 エアコン用コンプレッサまたはそれらの関連 製品に、 本発明のマグネシウム合金力 M吏用されると一層好適である。 具体的には、 内燃機関のシリンダへッド、 シリンダブ口ックゃオイルパン、 内燃機関のターボ チャージヤー用インペラ、 自動車等に用いられるトランスミッションケース等が 挙げられる。 C a is an element that forms C 14 and C 36 Laves structures together with Mg. If the Ca content is less than 2% by mass (ie, 1.235% by atom), precipitates and grain boundary crystals are not sufficiently formed, and the effect of improving heat resistance is not sufficient. It ’s not. On the other hand, if the Ca content exceeds 4% by mass (that is, 2.470% by atom), the amount of precipitates and grain boundary crystallized products will increase and cause problems in post-processing. This is not preferable. More preferably, the Ca content is 2.5 mass% or more and 3.5 mass% or less (that is, 1.5 4 atomic% or more and 2. 16 atomic% or less). Not limited to gravity, but it can also be die-cast. In addition, β used for forging does not matter whether it is a sand mold or a mold. There is no particular limitation on the cooling rate in the solidification process, but it is preferable to cool in the air. The use of the magnesium alloy of the present invention extends to various fields such as space, military and aviation, as well as automobiles and home electric Saito. However, the magnesium alloy strength of the present invention can be applied to products that are used in high-temperature environments by taking advantage of its heat resistance, such as engines, transmissions, compressors for air conditioners or related products that are installed in the engine compartment of automobiles. If used, it is more preferable. Specific examples include cylinder heads for internal combustion engines, cylinder plugs, oil pans, turbocharger impellers for internal combustion engines, transmission cases used in automobiles, and the like.
以上、 本発明の耐熱 ftマグネシウム合金の実施形態を説明したが、 本発明は、 上記実施形態に限定されるものではなレ、。 本発明の要旨を «しなレ、範囲にぉレヽ て、 当業者が行い得る変更、 改良等を施した種々の形態にて実施することができ る。  As mentioned above, although embodiment of the heat-resistant ft magnesium alloy of this invention was described, this invention is not limited to the said embodiment. The gist of the present invention can be implemented in various forms with modifications, improvements, etc. that can be made by those skilled in the art without departing from the scope of the present invention.
以下に実施例を挙げて、 本発明を具体的に説明する。  Hereinafter, the present invention will be specifically described with reference to examples.
マグネシウム合金中の A 1、 C aおよび Mnの含有量 （添加量） を変更した 2 種類の試験片をィ標し、 それらの金属紙織を観察するとともに応力緩和試験を行 つた。  Two types of specimens with different contents (addition amounts) of A1, Ca and Mn in the magnesium alloy were marked, and their metal paper weaves were observed and stress relaxation tests were performed.
[試験片の製造]  [Manufacture of specimens]
電気炉中で予熱した鉄製るつぼの内面に塩化物系のフラックスを塗布し、 その 中に秤量した純マグネシウム地金、 純 A l、 必要に応じて M g— Mn合金を投入 して溶解した。 さらに 7 5 0 °Cに保持したこの 易中に秤量した C aを添加した Chloride-based flux was applied to the inner surface of an iron crucible preheated in an electric furnace, and weighed pure magnesium ingot, pure Al, and Mg-Mn alloy as required, were dissolved. In addition, weighed Ca was added during this easy, which was maintained at 75 ° C.
(難調製工程） 。 (Difficult preparation process).
この溶湯を十分に攪拌し、 原料を完全に溶解させた後、 同 でしばらく沈静 保持した。 この溶解作業中、 M gの燃焼を防止するため、 溶驗面に炭酸ガスと S F 6ガスとの混合ガスを吹き付け、 適宜、 フラックスを溶 »面に散布した。 こうして得た各種の合金溶湯を所定の形状の金型に流し込み （注湯工程） 、 大 気雰囲気中で凝固させた （凝固工程） 。 こうして、 3 O ramX 3 0 O mmX 4 O ram の試験片を重力^ により製造した。 得られた試験片を # 0 1 (Mnを含む実施 例） 、 # C 1 (Mnを含まない比較例） とした。 各試験片の化学組成を表 1に示 す。 なお、 表 1のマグネシウム合金組成において、 残部は] VIgであるThe molten metal was sufficiently stirred to completely dissolve the raw materials, and then kept calm for a while. During this melting operation, in order to prevent Mg from burning, a mixed gas of carbon dioxide gas and SF 6 gas was sprayed on the hot metal surface, and flux was appropriately sprayed on the hot metal surface. The various alloy melts thus obtained were poured into a mold having a predetermined shape (a pouring process) and solidified in an atmosphere (solidification process). Thus, a 3 O ramX 30 O mmX 4 O ram test piece was manufactured by gravity. The obtained specimens were designated as # 0 1 (Example including Mn) and # C 1 (Comparative example not including Mn). Table 1 shows the chemical composition of each specimen. The In the magnesium alloy composition shown in Table 1, the balance is] VIg
[表 1] [table 1]
Figure imgf000012_0001
なお、 表 1では、 # 01およぴ# C 1の合金糸且成の単位として、 「質量0 /0」 お よび 「原子0 /0」 を用いる。 ここで、 単位 「質量0 /0」 を用いた値は、 溶湯調製工程 における仕込量であって、 その値を 「原子0 /0」 に換算している。
Figure imgf000012_0001
In Table 1, as the unit of # 01 Oyopi of # C 1 alloy yarn且成, using "mass 0/0" and the "atomic 0/0". Here, the value with the unit of "mass 0/0" is a charged amount in the molten metal preparing step, and converting the value to "atomic 0/0".
圆纖の観察:！  Obscenity observation :!
試験片# 01および #C 1を金属顕微鏡または透過電子顕微鏡 (TEM) で観 察した。 .  Specimens # 01 and # C1 were observed with a metal microscope or a transmission electron microscope (TEM). .
図 1は、 #01の試験片の断面を金属顕微鏡で観察した金属組織写真である。  Figure 1 is a metallographic photograph of a cross section of the # 01 test piece observed with a metallographic microscope.
Mg結晶粒 （明るい部分） および、 Mg結晶粒の粒界にネットワーク状に雜す る粒界晶出物 （黒い部分） が観察された。 なお、 図示しないが、 #C1の試験片 の断面を観察しても、 図 1と同様の金属紙織写真が得られた。 つまり、 レ、ずれの 試験片も、 巨視的には、 ネットワーク状の粒界晶出物が観察された。 Mg crystal grains (bright parts) and grain boundary crystallized grains (black parts) appearing in a network form at the grain boundaries of Mg crystal grains were observed. Although not shown, a metal paper weaving photograph similar to that in Fig. 1 was obtained by observing the cross section of the specimen # C1. In other words, macroscopically, grain-like crystallized crystals were observed in the specimens of the les and misalignments.
次に、 金属紙織の微細構造を観察するために、 各試験片を薄片状の観察試料と し、 TEMを用いて観察した。  Next, in order to observe the microstructure of the metal paper weave, each test piece was used as a flaky observation sample and observed using a TEM.
図 2および図 3は、 それぞれ、 #01および #C1の観察試料を TEMで観察 した金属紙織写真である。 どちらも、 2以上の初晶 Mgの結晶粒が互いに隣接す る結晶粒界を観察した。 図 2 (#01) では、 粒界晶出物 （黒い部分） はラメラ 状に成長し、 連続的であった。 図 3 (#C1) では、 粒界晶出物は部分的に途切 れて不連続であった。 なお、 #01のネットワークの被覆率は、 約 90%であつ Figures 2 and 3 are metal paper weaving photographs of # 01 and # C1 observed with TEM, respectively. In both cases, grain boundaries where two or more primary Mg grains were adjacent to each other were observed. In Fig. 2 (# 01), the grain boundary crystallization (black part) grew like a lamellar and was continuous. In Fig. 3 (# C1), the grain boundary crystals were partially discontinuous and discontinuous. The coverage of # 01 network is about 90%.
/し ο / Ο
また、 図 4および図 5は、 それぞれ、 #01および #C 1の観察試料の粒界晶 出物を観察した暗視野走査透過電子顕微鏡 （DF— STEM) 像である。 #01 の試験片は、 図 4に示すように相分離は見られないが、 #C 1の試験片は、 図 5 に示すように相分離が見られた。 図 4および図 5の DF— ST EM像に対してェ ネルギー分散型 X線分光法 (EDX) による元素マッピングを行うと、 図 4 (# 01) では Mg、 A 1および C aが均一に分布していたが、 図 5 (#C1) では 粒状に βして相分離した結晶粒において A 1の濃度が高かった。 そして、 A1 濃度の高い結晶粒からは、 C 36型結晶構造の電子回折が得られた。 一方、 図 4 および図 5において、 Mg、 A 1および C aがそれぞれ均一に分布している結晶 からは、 主として C14型結晶構造の電子回折パターンが得られたが、 一部、 相 分離していないにも力かわらず C 14型結晶構造の 2倍周期である C 36型結晶 構造の回折スポットが出現した。 すなわち、 Mg、 A 1および C aが均一に分布 している結晶は、 C 14型結晶構造と C 36型結晶構造との混晶相であり見た目 にほぼ単結晶であることがわかった。 したがって、 #01の試験片では、 ネット ワークを形成する粒界晶出物は、 微視的に連続的であって、 見た目にほぼ単結晶 になっていた。 一方、 #C 1の試験片では、 粒界晶出物は、 巨視的にはネットヮ ークを形成していても、 微視的には不連続であり、 C 36型結晶構造のみからな るラーべス相化合物が相分離して存在した。 Figures 4 and 5 are dark-field scanning transmission electron microscope (DF-STEM) images of the observed grain boundary crystals of the # 01 and #C 1 samples, respectively. The specimen of # 01 does not show phase separation as shown in Figure 4, but the specimen of #C 1 Phase separation was observed. When elemental mapping by energy dispersive X-ray spectroscopy (EDX) is performed on the DF—ST EM images in Figs. 4 and 5, Mg, A 1 and Ca are uniformly distributed in Fig. 4 (# 01). However, in Fig. 5 (# C1), the concentration of A 1 was higher in the grains that were separated into β and phase separated. Electron diffraction of the C36 crystal structure was obtained from the crystal grains with high A1 concentration. On the other hand, in Fig. 4 and Fig. 5, from the crystals in which Mg, A 1 and Ca are uniformly distributed, an electron diffraction pattern of C14 type crystal structure was mainly obtained, but partly phase-separated. Despite this, a diffraction spot of the C36 type crystal structure, which is twice as long as the C14 type crystal structure, appeared. In other words, it was found that the crystals in which Mg, A 1 and Ca are uniformly distributed are mixed crystal phases of C 14 type crystal structure and C 36 type crystal structure and are almost single crystals. Therefore, in the # 01 specimen, the grain boundary crystallized material forming the network was microscopically continuous and almost single crystal in appearance. On the other hand, in the #C 1 test piece, the grain boundary crystallized material is macroscopically discontinuous even though it forms a network, and consists only of a C36 type crystal structure. Laves phase compounds were present in phase separation.
なお、 図示しないが、 #01における Mn含有量を 0. 2質量％ (すなわち 0. 09原子0 /0) としたマグネシウム合金についても、 粒界晶出物を TEMで観察し た。 得られた DF— STEM像によれば、 Mn量が増加すると、 #C1 (図 5) に見られた塊状の凝集は減少して帯状に延びる化合物が多くを占めるようになる 力 S、 Mn含有量が 0. 2質量％では #01 (図 4) に観察される連続!"生は見られ ないことがわかった。 Although not shown, for the # 0.2 mass% of Mn content in 01 (ie 0.09 atom 0/0) and the magnesium alloy was observed grain boundary crystallized substances in TEM. According to the obtained DF-STEM image, when the amount of Mn increases, the agglomeration seen in # C1 (Fig. 5) decreases, and the compound extending in a strip shape occupies a large force. When the amount was 0.2% by mass, it was found that there was no life seen in # 01 (Fig. 4)!
図 6および図 7は試験片 #01、 図 8は試験片#( 1、 の TEM像である。 図 6は Alt方向をく 110>、 図 7および図 8は入射方向をく 111>として M.g 結晶粒内を観察した。 図 6 ' (# 01 ) では、 {001} 面に平行な筋状の析出物 が見られた。 そして、 図 6と同じ位置で入射方向を傾けて観察を行った図 7から、 析出物は、 {001} 面に5 Fffな板状であつた。 この板状析出物にっレ、て S T E M— EDX分析を行うと、 主として A 1および C aが検出された。.また、 板状析 出物からは、 A 12C aに一致する C 15型結晶構造の電子回折パターンが得ら れた。 Figures 6 and 7 are TEM images of specimen # 01 and Figure 8 is specimen # (1, 1. Figure 6 shows the Alt direction 110>, and Figures 7 and 8 show the incident direction 111> Mg. In Fig. 6 '(# 01), streaky precipitates parallel to the {001} plane were observed, and the incident direction was tilted at the same position as in Fig. 6. From Fig. 7, the precipitate was a plate with 5 Fff on the {001} plane, and when STEM-EDX analysis was performed on this plate-like precipitate, mainly A 1 and Ca were detected. In addition, an electron diffraction pattern of a C 15 type crystal structure corresponding to A 1 2 Ca was obtained from the plate-like precipitate. It was.
一方、 図 8 (#C1) では、 明確な筋状のコントラストは見られなかった。 な お、 #01と同様な STEM— EDX分析を行っても、 A 1や C aはほとんど検 出されなかった。 したがって、 #C1の試験片に析出物はほとんど しなかつ On the other hand, in Figure 8 (# C1), no clear streak contrast was found. Even when STEM-EDX analysis similar to # 01 was performed, A 1 and Ca were hardly detected. Therefore, there is almost no deposit on the specimen of # C1.
/こ / This
図 9は、 #01の観察試料の Mg結晶粒内を観察した DF— STEM像である。 板状の析出物の周囲に複数の微粒子が見られた。 微粒子 （図 9の B) について元 素分析を行うと、 Mnが検出された。 なお、 板状析出物を分析 （図 9の A) して も Mnは検出されなかった。  Figure 9 is a DF-STEM image of the observed # 01 observation sample in the Mg crystal grains. A plurality of fine particles were observed around the plate-like precipitate. When elemental analysis was performed on fine particles (B in Fig. 9), Mn was detected. Even when the plate-like precipitate was analyzed (A in Fig. 9), Mn was not detected.
[応力緩和試験]  [Stress relaxation test]
表 1に示した試験片 #01およぴ#(：1にカ卩え、 表 2に示す AXE662、 A E42、 AZ91D (すべて AS TM規格） 力 なるそれぞれの試験片について、 応力緩和試験を行い、 マグネシウム合金の耐熱性 （クリープ特性） を調べた。 応 力緩和試験は、 試験片に試験時間中、 所定の変形量まで荷重を加えたときの応力 が、 時間とともに減少する過程を測定する。 具体的には、 150°Cの大気雰囲気 中において、 試験片に 10 OMP aの圧縮応力を負荷し、 そのときの試験片の変 位が一定に保たれるように、 時間の経過に併せてその圧縮応力を低減していった。 表 2および表 3に、 各試験片の合金組成と、 応力緩和試験の 40時間後の応力 を示す。 なお、 表 2および表 3のマグネシウム合金組成において、 残部は Mgで ある。 また、 「RE」 はミッシュメタルである。  Specimens # 01 and # (shown in Table 1): AXE662, A E42, and AZ91D (all AS TM standards) shown in Table 2 were subjected to stress relaxation tests. The heat resistance (creep characteristics) of the magnesium alloy was investigated The stress relaxation test measures the process in which the stress when a load is applied to a specified amount of deformation during the test time decreases with time. Specifically, in an air atmosphere at 150 ° C, a compressive stress of 10 OMPa was applied to the specimen, and the displacement of the specimen at that time was kept constant along with the passage of time. Table 2 and Table 3 show the alloy composition of each specimen and the stress after 40 hours of the stress relaxation test, with the magnesium alloy compositions in Table 2 and Table 3. The balance is Mg, and “RE” is Misch Metal.
[表 2]  [Table 2]
Figure imgf000014_0001
[表 3]
Figure imgf000014_0001
[Table 3]
Figure imgf000015_0001
Figure imgf000015_0001
試験片 #01は、 他の試験片に比べ、 負荷される応力の減少割合が特に少なく、 高温下であっても高い耐クリープ性を示した。 これは、 Mnの存在により、 Mg 結晶粒の粒界に微視的に連続する強固なネットワークが形成されたこと、 Mg結 晶粒内の板状析出物で転位の移動が抑制されたこと、 により変形抵抗が大きくな り試験片# 01の強度が向上したためである。  Specimen # 01 showed a particularly low rate of decrease in applied stress compared to other specimens, and exhibited high creep resistance even at high temperatures. This is because, due to the presence of Mn, a strong microscopically continuous network was formed at the grain boundary of the Mg crystal grains, and the dislocation movement was suppressed by the plate-like precipitates in the Mg crystal grains. This is because the deformation resistance increased and the strength of specimen # 01 improved.

Claims

請求の範囲 The scope of the claims
1. 主成分のマグネシウム （Mg) と、 アルミニウム (A 1) およびニッケル (N i) から選ばれるいずれか一種以上の第一合金元素 Mlと、 マンガン （M n) 、 バリウム （Ba) 、 クロム （Cr) および鉄 (F e) 力 ら選ばれるいずれ か一種以上の第二合金元素 M 2と、 カルシウム （Ca) と、 を含み、 1. Magnesium (Mg) as the main component, one or more first alloy elements Ml selected from aluminum (A 1) and nickel (N i), manganese (M n), barium (Ba), chromium ( Including at least one second alloy element M 2 selected from Cr) and iron (F e) force, calcium (Ca), and
Mg結晶粒と、 該 Mg結晶粒の粒内に析出する板状の析出物と、 該 Mg結晶粒 の粒界に晶出して微視的に連続するネットワークを形成する粒界晶出物と、 を含 む金属 Mを有することを特徴とする耐熱性マグネシウム合金。  An Mg crystal grain, a plate-like precipitate that precipitates in the Mg crystal grain, and a grain boundary crystallized crystal that crystallizes at the grain boundary of the Mg crystal grain to form a microscopic continuous network; A heat-resistant magnesium alloy characterized by having a metal M containing.
2. 前記析出物は、 C15型結晶構造のラーべス相化合物からなる請求の範囲 第 1項記載の耐熱性マグネシゥム合金。  2. The heat-resistant magnesium alloy according to claim 1, wherein the precipitate comprises a Laves phase compound having a C15 type crystal structure.
3. 前記析出物は、 M g結晶の {001} 面に平行に析出する請求の範囲第 1 項記載の Hfit生マグネシゥム合金。  3. The Hfit raw magnesium alloy according to claim 1, wherein the precipitate is precipitated parallel to the {001} plane of the Mg crystal.
4. 前記粒界晶出物は、 Mg— Ml— C a系化合物からなる請求の範囲第 1項 記載の耐熱 14マグネシゥム合金。  4. The heat-resistant 14-magnesium alloy according to claim 1, wherein the grain boundary crystallized product is composed of an Mg—Ml—Ca-based compound.
5. 前記粒界晶出物は、 C 14型結晶構造と C 36 ¾結晶構造のラーべス相化 合物の混晶相からなる請求の範囲第 1項記載の耐熱性マグネシゥム合金。  5. The heat-resistant magnesium alloy according to claim 1, wherein the grain boundary crystallized material comprises a mixed crystal phase of a Laves phase compound having a C 14 type crystal structure and a C 36 ¾ crystal structure.
6, 前記混晶構造は、 C 36型結晶構造よりも C 14型結晶構造を多く含む請 求の範囲第 5項記載の画 ·熱性マグネシゥム合金。  6. The magnetothermal magnesium alloy according to claim 5, wherein the mixed crystal structure includes a C14 type crystal structure more than a C36 type crystal structure.
7. 前記 M g結晶粒内に M 2を含む微粒子を有する請求の範囲第 1項記載の耐 熱性マグネシウム合金。  7. The heat-resistant magnesium alloy according to claim 1, which has fine particles containing M 2 in the Mg crystal grains.
8. 全体を 100質量％としたときに、 Caを 2質量％以上 4質量％以下、 前 記第一合金元素 Mlを C aに対する質量比 (Ml/Ca) で 0. 9以上 1. 1以 下、 前記第二合金元素 M2を 0. 3質量。/。以上 0. 6質量％以下含み、 残部が M gおよび不可避不純物からなる請求の範囲第 1項記載の耐熱性マグネシウム合金。 8. When the total is 100% by mass, Ca is 2% by mass or more and 4% by mass or less, and the above-mentioned first alloy element Ml is 0.9 or more by mass ratio (Ml / Ca) with respect to Ca 1.1 or more Below, 0.3 mass of the second alloy element M2. /. 2. The heat-resistant magnesium alloy according to claim 1, comprising 0.6% by mass or less and the balance being Mg and inevitable impurities.
9. 前記第二合金元素 M2を 0, 3質量％以上0. 5質量％以下含む請求の範 囲第 8項記載の耐 m性マグネシゥム合金。 9. The m-resistant magnesium alloy according to claim 8, wherein the second alloy element M2 is contained in an amount of 0.3 to 0.5% by mass.
10. 全体を 100原子％としたときに、 Caを 1. 235原子％以上 2. 4 70原子0 /。以下、 前記第一合金元素 Mlを C aに対する原子比 (Ml/Ca) で10. Ca is 1.235 atomic% or more when the whole is 100 atomic% 2.4 70 atoms 0 /. Hereinafter, the first alloy element Ml is expressed in terms of atomic ratio (Ml / Ca) with respect to Ca.
I. 34以上1. 63以下、 前記第二合金元素 M2を 0. 13原子％以上 0. 2 7原子％以下含み、 残部が M gおよび不可避不純物からなる請求の範囲第 1項記 載の耐熱 (·生マグネシウム合金。 I. 34 or more and 1.63 or less, the second alloying element M2 is contained in an amount of 0.13 atomic% or more and 0.2 7 atomic% or less, and the balance consists of Mg and inevitable impurities. (· Raw magnesium alloy.
I I . 膽己第二合金元素 M 2を 0. 15原子％以上 0. 25原子％以下含む請 求の範囲第 10項記載の耐熱性マグネシウム合金。  I I. The heat-resistant magnesium alloy according to claim 10, which contains 0.12 atomic% or more and 0.25 atomic% or less of the second alloy element M 2.
12. 歯己第一合金元素は A 1、 前記第二合金元素は M nである請求の範囲第 12. The first alloy element is A 1 and the second alloy element is M n.
1項記載の »熱 1·生マグネシゥム合金。 1. Thermal 1 · raw magnesium alloy as described in item 1.
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