Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
  • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
  • B21B3/003—Rolling non-ferrous metals immediately subsequent to continuous casting, i.e. in-line rolling
• • 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
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/06—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of magnesium or alloys based thereon

Definitions

• One embodiment of the present invention relates to a magnesium alloy sheet and a method of manufacturing the same.
• magnesium has a density of 1.74 g / citf, which is the lighter metal than other structural materials such as aluminum and steel, and has various advantages such as vibration absorption ability and electromagnetic wave shielding ability. .
• Such magnesium-containing alloys are currently being applied not only to the field of electronic devices but also to the automobile field, but they have a fundamental problem in corrosion resistance, flame retardancy, and moldability, and thus there is a limit to expanding the range of their applications.
• magnesium has an HCP structure (Hexagonal Closed
• the AZ-based alloys include aluminum (A1) and zinc (Zn), and they are inexpensive while securing the physical properties with appropriate strength and ductility to some extent and they correspond to commercially available magnet alloys .
• the above-mentioned physical properties mean an appropriate level of magnesium alloy, and the strength is lower than that of aluminum (Al) which is a competitive material. Therefore, it is necessary to improve the physical properties such as low moldability and strength of the KL-based magnesite alloy, but research on this has not yet been made.
• a magnesium alloy sheet material and a method of manufacturing the same.
• the magnesium alloy sheet material according to one embodiment of the present invention is composed of A1: 2.7 to 5.0 wt%, Zn: 0.75 to 1.0 wt%, Ca: 0.1 to 1.0 wt%, Mn: 1.0 wt% (0% by weight), the balance Mg and other unavoidable impurities, and the volume fraction of the bottom grain is not more than 3OT with respect to 100% by volume of the total crystal grains of the magnesium alloy sheet material, and the bottom grain ⁇ It is possible to provide a magnesium alloy sheet material which is a crystal grain in the C axis orientation.
• the magnesium alloy sheet material comprises a quaternary portion including Al-Ca secondary phase particles, the quarter portion being a quarter point from the surface of the magnesium alloy sheet material, and an Al-Ca secondary portion
• the difference in the area fraction of the phase particles may be less than or equal to 1.
• the ratio of the length of the intermediate segregation to the total length in the rolling direction of the magnesium alloy sheet material may be less than 5%.
• the thickness ratio of the intermediate segregation may be less than 2.5% of the total thickness in the thickness direction of the magnet alloy sheet material.
• the magnesium alloy sheet material may have M-Ca secondary phase particles uniformly distributed without being segregated in the central portion of the magnesium alloy material.
• the Al-Ca secondary phase particles are composed of Al: 20.0 to 25.0 wt%, Ca: 5.0 to 10.0 wt%, Mn: 0.1 to 0.5 wt%, Zn: 0.5 to 1.0 wt% Mg and other unavoidable impurities.
• the average particle diameter of the Al-Ca secondary phase particles may be from 0 1 to 4.
• the Al-Ca secondary phase particles may include 2 to 15 particles per 100 2 of the magnet alloy tube.
• the magnesium alloy sheet may have a threshold tensile strength (LDH) of 7 or more.
• LDH threshold tensile strength
• the maximum gathering strength may be 1 to 4 on the basis of the magnesium alloy sheet (0001) plane.
• a magnesium alloy sheet according to another embodiment of the present invention is a magnesium alloy sheet having a composition of A1: 2.7-5.0 wt%, Zn: 0.75-1.0 wt%, Ca: 0.1-1.0 wt%, Mn: 1.0 wt% (Excluding 0 wt.%), The balance Mg and other unavoidable impurities, and the area fraction of the twin crystal structure is 35% or less with respect to 100% of the total area of the magnesium alloy plate material.
• the area fraction of the twin crystal structure may be 5 to 35%.
• the volume fraction of the bottom grain is 30% or less with respect to 100 parts by mass of the entire magnesium alloy plate grain, and the bottom grain is a crystal grain of the C axis orientation.
• the limit dome height of the magnet alloy sheet material may be 7 mm or more.
• the maximum gathering strength may be 1 to 4 on the basis of the magnet alloy sheet (0001) plane.
• the yield strength of the magnesium alloy sheet material may be 200 to 300 MPa.
• the magnesium alloy sheet according to one embodiment of the present invention can improve the moldability of the magnesium plate by dispersing the center segregation composed of Al-Ca secondary phase particles. Accordingly, the magnesium alloy sheet according to an embodiment of the present invention is characterized in that the Al-Ca secondary phase is a magnet alloy A plate material can be provided. Specifically, the difference in area fraction of Al-Ca secondary phase particles at a quarter of the surface of the magnesium alloy sheet and the center of the half of the magnesium alloy sheet surface is 10% or less, A plate material can be provided.
• Magnet alloy sheet according to another embodiment of the present invention can obtain a magnesium alloy sheet having an area fraction of the twin crystal structure of 35% or less with respect to 100% of the total area of the magneto alloy sheet through skin pass rolling. Specifically, the development of the (0001) texture is minimized through the skin pass process, and the strength can be improved by controlling the twin texture while maintaining the moldability.
• FIG. 1 is a schematic flowchart of a method of manufacturing a magnesium alloy sheet according to an embodiment of the present invention.
• Example 2 is an optical microscope photograph of the magnesium alloy sheet produced in Example la.
• Example 4 is a secondary electron microscopic photograph of the magneto-alloy plate produced in Example la.
• FIG. 5 shows the measurement results of the limiting dome height of the magnesium alloy sheet produced in Example la.
• Example 6 shows the aggregate intensities of the maximum (0001) planes of Example la.
• 7 shows the aggregate intensity of the maximum (0001) plane of Comparative Example la. 8 is a result of analyzing the magnesium alloy sheet produced in Example la by EBSD (Electron Backseat Dielectric Fraction).
• EBSD Electro Backseat Dielectric Fraction
• FIG. 9 is a graph showing the fraction of the crystal orientation of Example la.
• FIG. 10 shows the result of analysis of the magnesium alloy sheet material by EBSD according to the skin pass reduction rate.
• Magnesium alloy sheet according to one embodiment of the present invention comprises 2.7 to 5.0% by weight of Al, 0.75 to 1.0% by weight of Zn, 0.1 to 1.0% by weight of Ca, , Mn: not more than 1.0 wt% (not more than 0 wt%), the balance Mg and other unavoidable impurities.
• Al improves the mechanical properties of the magnesium alloy sheet material and improves the casting of the melt. If Al is added in an amount of more than 5.0 wt%, the main composition may deteriorate rapidly. If Al is added in an amount less than 2.7 wt%, the mechanical properties of the magnesium alloy sheet material may deteriorate. Therefore, the content range of Al can be adjusted within the above-mentioned range.
• Zinc (Zn) improves the mechanical properties of the magnesium alloy sheet.
• Zn Zinc
• the foxes (Ca) impart flame retardancy to the magnesium alloy sheet.
• Ca When Ca is added in an amount of more than 1.0% by weight, the flowability of the molten metal is decreased to deteriorate the casting composition, and the center segregation of the Al-Ca based intermetallic compound is increased to cause a problem of deteriorating the moldability of the magnesium alloy plate . If Ca is added in an amount of less than 0.1% by weight, there may arise a problem that flame retardancy is not imparted to the layer. Therefore, the content range of Ca can be adjusted within the above-mentioned range. More specifically, Ca may be contained in an amount of 0.5 to 0.8% by weight.
• Manganese (Mn) improves the mechanical properties of the magnet alloy sheet. If Mn is added in an amount of more than 1.0% by weight, the heat dissipation property may be deteriorated and a problem that the uniform distribution control may become difficult may arise. Therefore, the content range of Mn can be controlled within the above-mentioned range.
• the volume fraction of the bottom grain may be 30% or less.
• the bottom crystal grains means a crystal grains having a bottom orientation.
• magnesium has an HCP hexagonal closed pack crystal structure.
• the crystal grains when the C axis of the crystal structure is parallel to the thickness direction of the plate are crystal grains having a bottom crystal orientation (that is, bottom crystal grains) do.
• the bottom grain can be represented by " < 0001 > // C axis ".
• the volume fraction of crystal grains having a C-axis orientation relationship may be 30% or less. More specifically, with respect to 100 vol% of the entire crystal grains of the magnesium alloy sheet, the volume fraction of crystal grains in the C-axis orientation may be 25% or less. More specifically, it may be 20% or less.
• the volume fraction of the grains having the orientation relationship of < 0001 > // C axis may exceed the lower limit. This is because the ⁇ 0001 > // C axis And it is within the scope of the present invention that the volume fraction of crystal grains having a bearing relationship exists.
• the crystal fraction fraction of the C axis orientation may decrease.
• the magnesium alloy sheet material having a lower aggregate strength and excellent moldability can be obtained.
• the magnesium alloy sheet according to an embodiment of the present invention may include Al-Ca secondary phase particles.
• the magnesium alloy sheet according to an embodiment of the present invention includes
• the magnesium alloy sheet according to one embodiment of the present invention comprises
• Al-Ca secondary phase particles may be evenly dispersed.
• Center segregation means that Al-Ca secondary phase particles are segregated at the center of the magnet plate in the thickness direction (ND) of the magnet alloy plate material. As described above, if the center segregation increases, the moldability of the magnet alloy plate material may deteriorate .
• the magneto-alloy plate according to an embodiment of the present invention has a quarter portion at a quarter point from the surface
• the difference in the area fraction of the Al-Ca secondary phase particles at the center, which is 1/2 point, may be less than 10%.
• the Al-Ca secondary phase particles are uniformly dispersed as a whole without being segregated at the center portion, and the formability can be improved.
• the area fraction means a fraction of the area of the Al-Ca secondary phase particles per the same area in the quarter portion and the center portion.
• the ratio of the length of the intermediate segregation to the total length in the rolling direction RD of the magnesium alloy sheet material may be less than 53 ⁇ 4>. Further, the thickness ratio of the intermediate segregation may be less than 2.5% with respect to the total thickness in the thickness direction (ND) of the magnesium alloy sheet material.
• the above-mentioned base material means that almost no center segregation is formed. Generally, the length of the segregation is smaller than the center segregation generated when Al and Ca are added. The thickness is all reduced. Accordingly, the magnesium alloy sheet, which is an embodiment of the present invention, can improve the moldability.
• the total length of the magnesium plate may be based on a magnesium plate of a predetermined length. Specifically, the length unit may be 1, 000 to 3, 000 zm.
• the magneto-alloy plate according to one embodiment of the present invention can suppress the formation of center segregation composed of Al-Ca secondary phase particles and improve the moldability of the magnet plate. Specifically, it is possible to provide a magnet alloy sheet material in which Al-Ca secondary phase particles are dispersed.
• the average particle size of the Al-Ca secondary phase particles may be 0.01 to 4.
• Al-Ca secondary phase particle size of 100 of the thoracic magnesium alloy plate may include 2 to 15 per «m 2.
• the moldability of the magnesium alloy sheet material can be improved.
• the composition range of A1, Zn, Mn and Ca, the temperature and time conditions in the homogenization heat treatment, the temperature and the rolling rate during hot rolling can be precisely controlled have.
• the magnesium alloy sheet material includes crystal grains, and the average grain size of the crystal grains may be 5 to 30 liters.
• the formability can be improved in the grain size range.
• the limit imposed height of the magnesium alloy sheet according to an embodiment of the present invention may be 7 mm or more. More specifically, it may be 7 to 10 times.
• the limit dome height is used as an index for evaluating the formability (in particular, compressibility) of a material, and means that the moldability of the material is improved as the height of the limit dome increases.
• the above limited range is a marginal dome height which is significantly higher than a generally known magnesium alloy plate due to an increase in the orientation distribution of the crystal grains in the magnesium alloy sheet material.
• the magnesium alloy sheet may have a maximum aggregate strength of 1 to 4 based on the (0001) plane. If it exceeds the above-mentioned range, the moldability of the magnesium alloy sheet material may be inferior.
• the yield strength of the magnesium alloy sheet according to an embodiment of the present invention can be in the range of 150 to 190 MPa.
• Magnet alloy sheet according to an embodiment of the present invention may have an area fraction of twin crystal structure of 35% or less with respect to 100% of the total area of the magnesium alloy sheet material through skin pass rolling in the manufacturing step described later. More specifically, the area fraction of twinning tissue can be from 5 to 35%. More specifically, the area fraction of the twin tissue may be between 5 and 33%.
• the yield strength of the magneto-alloy plate according to an embodiment of the present invention may be 200 to 300 MPa. This range is considered to be an excellent range for the magnet plate of the component according to one embodiment of the present invention.
• the thickness of the magnesium alloy sheet according to an embodiment of the present invention may be 0.4 to 3 thighs.
• the magneto plate according to an embodiment of the present invention can be selected according to the properties required in the thickness range. However, the present invention is not limited thereto.
• FIG. 1 schematically shows a flowchart of a method of manufacturing a magnesium alloy sheet according to an embodiment of the present invention.
• the flow chart of the method of manufacturing the magnesium alloy sheet material of FIG. 1 is for illustrating the present invention only, and the present invention is not limited thereto. Therefore, the manufacturing method of the magnesium alloy sheet material can be variously modified.
• a method for manufacturing a magnet alloy sheet material comprises A1: 2.7 to 5.0 wt%, Zn: 0.75 to 1.0 wt%, Ca: 0.1 To 1.0 wt.% Mn: 1.0 wt.% Or less (excluding 0 wt.%), The balance Mg and other unavoidable impurities to produce a casting material (S10); A step (S20) of homogenizing the cast material; And a step (S30) of silver-rolling the homogenized heat-treated cast material.
• the manufacturing method of the magnesium alloy sheet material may further include other steps.
• the method (S10) for manufacturing the cast material may be a die casting, a strip casting, a billet casting, a centrifugal casting, a tilting casting, a casting casting, a direct chill casting or a combination thereof. More specifically, a strip casting method can be used. However, the present invention is not limited thereto.
• the pressing force may be 0.2 t on / mm 2 or more. More specifically, it may be lton / cm 2 or more. More specifically, it may be from 1 to 1.5 ton / 2 2 2 .
• the casting material is solidified, it is subjected to a pressing force. At this time, the moldability of the magnesium alloy sheet material can be improved by adjusting the pressing force to the above range.
• step (S20) of homogenizing the cast material may be performed.
• the heat treatment conditions can be heat treated at a temperature of 350 ° C to 500 ° C for 1 to 28 hours. More specifically, homogenization for 18 to 28 hours. Heat treatment can be performed.
• the homogenization heat treatment can be performed within the above-mentioned temperature range.
• step (S30) of warm rolling the cast material subjected to the homogenization heat treatment can be performed.
• the temperature condition of the warm rolling may be 150 ° C to 350 ° C.
• a problem in which a large number of edge cracks occur may occur in a temperature range lower than 150 ° C.
• Problems that are not suitable for mass production may occur in a temperature range higher than 500 ° C. Therefore, hot rolling can be performed within the temperature range described above.
• the hot rolling step may be performed a plurality of times
• Hot rolling can be performed at a reduction ratio of 30%.
• the reduction rate of the warm rolling refers to the% value with respect to the thickness 100% (length%) of the cast material before warm rolling.
• the intermediate annealing step may be further performed at least one time during a plurality of warm rolling steps. Further comprising the step of intermediate annealing, the moldability of the magnesium alloy sheet material can be further improved. Specifically, the intermediate annealing step may be carried out at a temperature of 300 to 50 CTC for 1 to 10 hours. More specifically, it can be carried out at a temperature of 450 to 500 ° C. The moldability of the magnesium alloy sheet material can be further improved in the above-mentioned range.
• the hot rolling step may further include a post heat treatment step.
• the post-heat treatment step is further included, whereby the moldability of the magnesium alloy sheet material can be further improved.
• the post-heat treatment may be carried out at 300 to 500 ° C for 1 to 15 hours. Specifically, the reaction can be carried out for 1 to 10 hours.
• the moldability of the magnet alloy sheet material can be further improved in the above-mentioned range.
• Another method for producing a magnet alloy sheet according to an embodiment of the present invention comprises: A1: 2.7 to 5.0 wt%; 0.75 to 1.0 wt% of Zn; 0.1 to 1.0 wt% of Ca based on 100 wt% By weight, Mn: not more than 1.0% by weight (excluding 0% by weight), the balance Mg and other unavoidable impurities; Subjecting the cast material to homogenization heat treatment; The homogenization Warm-rolling the heat-treated cast material to produce a rolled material; Post-heat treating the rolled material; And subjecting the post-heat treated rolled material to a skin pass to produce a magnesium alloy sheet material.
• the melt may be an AZ31 alloy, AL5083 alloy, or a combination thereof already commercialized.
• the present invention is not limited thereto.
• the molten metal can be prepared in the temperature range of 650 to 750 ° C. Thereafter, the molten metal can be cast to produce a cast material. At this time, the thickness of the cast material may be 3 to 7 mm.
• the casting material may be manufactured by die casting, strip casting, billet casting, centrifugal casting, tilt casting, sand casting, direct chill casting, or a combination thereof. More specifically, a strip casting method can be used. However, the present invention is not limited thereto.
• the pressing force in the step of producing the cast material may be 0.2 ton / mm 2 or more. More specifically, it may be lton / cm 2 or more. More specifically, it may be from 1 to 1.5 ton / cm 2 .
• the step of homogenizing the cast material may be performed. More specifically, the step of subjecting the cast material to a homogenizing heat treatment may include: a first heat treatment step at a temperature range of 30CTC to 400C; And a second heat treatment step in a temperature range of 400 ° C to 500 ° C; . ≪ / RTI > The silver ranges of the primary heat treatment step and the secondary heat treatment step may be different.
• the first heat treatment step in the silver range it is possible to remove the Mg-Al-Zn ternary system wave generated in the casting step. If there is more than the above three-way wave, it may adversely affect subsequent processes.
• the second heat treatment step in the above-mentioned temperature range it is possible to loosen the force in the slab.
• formation of recrystallization of the cast structure can be further actively induced. Thereafter, the homogenized heat-treated cast material is warm-rolled to produce a rolled material.
• the heat treated cast material can be rolled to a range of 0.4 to 3 mm thickness through one to fifteen times rolling. Further, the rolling can be carried out at 150 to 350 ° C.
• the step of intermediate annealing the rolled material may be performed.
• between the pass and the pass interval in 30CTC to 550 ° C The silver range can be heat-treated for 1 hour to 15 hours.
• it may be subjected to intermediate annealing once after twice rolling, and then rolled to a final target thickness.
• it may be rolled three times and then annealed once to the final target thickness. More specifically, when the rolled cast material is annealed in the above temperature range, the stress generated by rolling can be released. Therefore, the desired casting material can be rolled several times to the thickness.
• the step of post-heat-treating the rolled material may be performed.
• the post heat treatment may be carried out at 300 to 50 CTC for 1 to 15 hours. Specifically, the reaction can be carried out for 1 to 10 hours.
• the moldability of the magnet alloy sheet material can be further improved in the above-mentioned range.
• a skin pass may be applied to the post-heat treated rolled material to produce a magnesium alloy sheet material.
• the skin pass is also referred to as temper rolling or tempering, and after the heat treatment .
• temper rolling or tempering
• the deformed pattern formed on the rolled steel sheet is removed and the rolled steel sheet is lightly rolled to improve the hardness.
• a single skin pass may be performed at a temperature range of 250 ° C to 35 ° C.
• the magnesium alloy sheet material produced by the skin pass may be rolled at a reduction ratio of 2 to 15% with respect to the thickness of the rolled material. More specifically, the reduction rate can be interlocked with the skin pass temperature.
• the skin pass reduction rate may be 5 to 15%.
• the yield strength range may be 200 to 260 MPa.
• the threshold level may be in the range of 7.3 to 8.1.
• the skin pass reduction rate may be 5 to 15%. More specifically, it may be from 7 to 12%. At this time, the yield strength range may be 200 to 250 MPa.
• the limit dome height may range from 7.3 to 8.1.
• the limit dome height is an index for evaluating the formability of a plate, particularly pressability.
• the deformed height of the specimen can be measured to determine the moldability. If the height value of the limit dome is high, it can mean that the formability of the plate is excellent.
• the formability can be secured. That is, when the skin pass is performed under the above conditions, the change in the texture strength of the texture can be minimized and the strength can be improved.
• A1 and Ca are included as set forth in Table 1 below and Zn. 0.8 wt%, Mn 0.5 wt%, the remainder Mg and unavoidable impurities were prepared.
• the molten metal was passed through two angles to produce a magnesium cast material. At this time, the lowering force of cooling is as shown in Table 1 below. Then, the magnesium cast material was subjected to homogenization heat treatment at a temperature of 400 ° C for different times as shown in Table 1 below.
• the homogenized heat treated cast product was hot rolled at a temperature of 250 ° C at a reduction rate of 15%. Thereafter, intermediate annealing was performed at the temperature shown in Table 1 for 1 hour, and then hot rolled at a reduction rate of 15% at a temperature of 250 ° C to produce a magnesium alloy sheet.
• a ⁇ and Ca were included as described in Table 1 below, and a melt containing 0.8% by weight of Zn, the balance Mg and unavoidable impurities was prepared.
• Magnet alloy sheets were prepared in the same manner as in Example 1, except for the conditions described in Table 1 below. .
• A1 Content Ca content Mainly homogenization Rolling temperature Medium annealing (weight% by weight) (ton / thigh 2 ) Annealing time (hr) ⁇ Temperature ( ° C)
• Example Example 3 0.6 1.2 24 250 500 Example lg 3 0.7 0.2 24 250 500
• the following test examples were conducted.
• Test Example 1 Microstructure observation of a magnesium alloy sheet
• Example la 2 is a scanning electron microscope (SEM) photograph of the magneto-alloy plate produced in Example la. 3 is a scanning electron micrograph of the magnesium alloy sheet produced in Comparative Example la.
• Comparative Example la in the case of Comparative Example la, it can be seen that a large amount of center segregation occurred. Specifically, in Comparative Example la, the ratio of the length of the center segregation to the total length of about 2000 in the rolling direction is 5% or more. In addition, in Comparative Example la, the total thickness in the thickness direction was about 1200, and the thickness of the middle segregation was about 30 / mi. Therefore, it can be seen that the thickness ratio of the middle segregation is 2.5% with respect to the total thickness in the thickness direction of the magnesium alloy sheet material. Therefore, it was confirmed that Comparative Example la produced a large amount of center segregation.
• the magnesium alloy sheet material having excellent moldability can be obtained as the center segregation is not generated.
• FIG. 4 is a secondary electron microscopic photograph of the magnesium alloy sheet produced in Example la.
• the white dot means an Al-Ca secondary phase particle. More specifically, the white point portion of FIG. 4 was analyzed to be composed of 24.61% by weight of Al, 8.75% by weight of Ca, 0.36% by weight of Mn, 0.66% by weight of Zn, balance Mg and other unavoidable impurities. From this, it was confirmed that the magnesium alloy sheet according to Example 1a contains Al-Ca secondary phase particles. Specifically, FIG. 4 shows that 50 secondary phase particles of Al-Ca are distributed per 1600 2 of magneto-alloy plate material area.
• Example la in the case of Example la, it can be seen that the Al-Ca secondary phase is dispersed without being segregated. From this, as shown in Table 2 below, it can be seen that the limit tread height of Example 1a is 9.4 ⁇ , while the limit dome height of Comparative Example la is 2.5 torsion, and the formability is improved compared to the embodiment.
• Test Example 2 Measurement of Magnet Alloy Sheet and Threshold Level
• LDH Limit Dome Height
• Magnet alloy sheets according to Examples and Comparative Examples were inserted between the upper die and the lower die, and the outer circumferential portion of each test piece was fixed with a force of 5 kN.
• a known press oil was used as the lubricant. Then, a strain was applied at a speed of 5 to 10 mm / min using a spherical punch having a diameter of 20 I thighs. After inserting the patch until each test piece was broken, the deformation height of each test piece . That is, the measured height of the specimen was measured.
• FIG. 5 shows the measurement results of the limiting dome height of the magnesium alloy sheet produced in Example la.
• Test Example 3 Analysis of crystal orientation of crystal grains The crystal orientations of the crystal grains of the magnesium alloy plate material by the examples and the barrels were confirmed with an XRD analyzer and are shown in Figs. 6 to 11. Fig. Specifically, the texture of the crystal grains is shown by using the XRD pole figure method (Pole figure) method.
• the pole figure is a stereo projection of the direction of the arbitrarily fixed crystal coordinate system in the sample coordinate system. More specifically, the poles for the ⁇ 0001 ⁇ planes of the crystal grains of various orientations can be displayed in the reference coordinate system, and the poles can be represented by plotting density contours according to the poles density distribution. At this time, the poles are fixed in a specific lattice direction by the Bragg angle, and a plurality of poles can be displayed for a single crystal.
• the maximum aggregate intensities of the (0001) planes of FIGS. 6 and 7 are the results of analyzing the crystal orientation of the magnet alloy plate by the above-described XRD analyzer.
• the embodiment shows that the maximum density distribution value (aggregate intensity) of the (0001) plane is as low as 2/73, whereas the comparative example is 12. 1, which is higher than the embodiment.
• the maximum aggregate intensity value is small and the contour lines are widely spread and the crystal grains of various orientations are distributed in the embodiment.
• the comparative example since the maximum set intensity value is large and the contour lines are densely packed, it can be seen that the comparative example contains much crystal grains of the orientation ⁇ 0001 > // C axis.
• the embodiment is more excellent in moldability.
• FIG. 8 This can be seen from FIG. 8 and FIG.
• Example 8 is a result of analysis of the magnesium alloy sheet material produced in Example la by EBSD (Electron Backseat Diaphragm Fracture).
• 9 is a graph showing the fraction of the crystal orientation of Example la.
• crystal orientation of crystal grains can be measured by using EBSD. More specifically, the EBSD can inject electrons into a specimen through an e-electron beam and measure the crystal orientation of the crystal grains using inelastic scattering diffraction at the back of the specimen.
• the orientation difference is 20 ° or less between the crystal grains the grain as disclosed in Fig. 9 as the bottom surface grain.
• the volume fraction of the ⁇ 0001 > // C axis bearing grain was found to be about 18.5%.
• the formability was improved compared with the examples.
• the yield strength is also shown in the examples.
• the average size of the grains was 40 im, which was comparatively superior to the other comparative examples, but was far below the examples.
• a molten metal containing A1: 3.0 wt%, Zn: 1.0 wt%, Ca: 1.0 wt%, Mn: 0.3 wt%, and the balance Mg and other baffled impurities was prepared for 100 wt%
• the above molten metal was cast to produce a cast material.
• the cast material was subjected to a primary homogenization heat treatment at 35 CTC for 10 hours.
• the primary homogenized heat-treated cast material was subjected to a secondary homogenization heat treatment at 450 ° C for 10 hours.
• the homogenized heat-treated cast material was rolled to produce a rolled material.
• the post-heat-treated rolled material was subjected to a skin pass to prepare a magnesium plate.
• the temperature and the reduction rate of the skin pass were as shown in Table 2.
• a magnet alloy sheet material was produced in the same manner as in Example 2, except for the skin pass temperature and the reduction ratio.
• Test Example 4 Comparison of physical properties of skin pass reduction rate and temperature
• the skin pass of the magnesium alloy having the same composition and composition resulted in improved yield strength without significantly changing the formability. More specifically, the formability can be compared with the elongation and the limit dome height.
• FIG. 10 shows the result of analysis of the magnesium alloy sheet material by EBSD according to the skin pass reduction rate. As shown in Fig. 10, it can be seen that the crystal grains of various orientations are distributed even when the skin pass is further performed after the rolling. In addition, when the skin pass reduction rate is increased and rolled, twinning (black) texture and dislocation developments can minimize the azimuthal change of the texture and improve the strength.
• the area fraction of the twin tissue is found to be 15% with respect to the entire area of 100%.
• the area fraction of the twin tissue was found to be 30% for the entire area 100%.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Metal Rolling (AREA)
• Hard Magnetic Materials (AREA)

Priority Applications (6)

Applications Claiming Priority (3)

Publications (1)

Family

ID=64735780

Family Applications (1)

Country Status (7)

Families Citing this family (1)

Citations (5)

Family Cites Families (5)

• 2017
  • 2017-06-23 KR KR1020170079982A patent/KR20190000676A/ko not_active Application Discontinuation
• 2018
  • 2018-06-21 CN CN201880042004.2A patent/CN110785506A/zh active Pending
  • 2018-06-21 JP JP2019570977A patent/JP2020524219A/ja active Pending
  • 2018-06-21 EP EP18820051.3A patent/EP3643802A4/en not_active Withdrawn
  • 2018-06-21 CA CA3068201A patent/CA3068201A1/en not_active Abandoned
  • 2018-06-21 WO PCT/KR2018/007030 patent/WO2018236163A1/ko unknown
  • 2018-06-21 US US16/625,452 patent/US20210147964A1/en not_active Abandoned

Patent Citations (5)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events