JPH08229663A - Metal sintered composite material - Google Patents
Metal sintered composite materialInfo
- Publication number
- JPH08229663A JPH08229663A JP3738195A JP3738195A JPH08229663A JP H08229663 A JPH08229663 A JP H08229663A JP 3738195 A JP3738195 A JP 3738195A JP 3738195 A JP3738195 A JP 3738195A JP H08229663 A JPH08229663 A JP H08229663A
- Authority
- JP
- Japan
- Prior art keywords
- composite material
- sintered body
- layer
- aluminum alloy
- thermal expansion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は金属焼結体複合材料に関
する。本発明に係る金属焼結体複合材料は例えば摺動部
材、具体的には内燃機関のピストンのピストンリング溝
を形成する領域などに適用できる。FIELD OF THE INVENTION The present invention relates to a sintered metal composite material. The metal sintered body composite material according to the present invention can be applied to, for example, a sliding member, specifically, a region where a piston ring groove of a piston of an internal combustion engine is formed.
【０００２】[0002]
【従来の技術】特開平３−１８９０６３号公報、特開平
３−１８９０６４号公報には、金属粉末を焼結した多孔
質金属焼結体を用い、多孔質金属焼結体の気孔部分にア
ルミ系、マグネシウム系等の軽金属を含浸、固化させた
複合材料部をもつ金属焼結体複合材料に関する技術が提
案されている。2. Description of the Related Art Japanese Patent Application Laid-Open Nos. 3-189063 and 3-189064 use a porous metal sintered body obtained by sintering a metal powder, and use an aluminum-based material in the pores of the porous metal sintered body. , A technique related to a metal-sintered composite material having a composite material part impregnated and solidified with a light metal such as magnesium-based material has been proposed.
【０００３】また上記公報によれば、上記複合材料部を
構成する軽金属と同材質の軽金属母材部で、複合材料部
を覆う技術も開示されている。The above publication also discloses a technique of covering the composite material portion with a light metal base material portion made of the same material as the light metal forming the composite material portion.
【０００４】[0004]
【発明が解決しようとする課題】上記した金属焼結体複
合材料の温度を急激に変化させる際に、例えば、高温領
域に加熱した直後の金属焼結体複合材料を急冷処理する
際に、複合材料部と軽金属母材部との界面において亀裂
が発生することが往々にしてある。軽金属が含浸される
多孔質金属焼結体を構成する原料として、強度、弾性
率、耐摩耗性等の特性及びコスト等の観点から鉄系が選
択されることが多いが、鉄系の焼結体を用いた場合に
は、金属焼結体複合材料の温度を急激に変化させる際
に、軽金属母材部と複合材料部との界面において亀裂が
発生し易い。When the temperature of the above-mentioned metal sintered body composite material is rapidly changed, for example, when the metal sintered body composite material immediately after being heated to a high temperature region is subjected to quenching treatment, A crack often occurs at the interface between the material part and the light metal base material part. As a raw material for forming a porous metal sintered body impregnated with a light metal, iron-based materials are often selected from the viewpoints of properties such as strength, elastic modulus, wear resistance, etc., and cost. When the body is used, cracks are likely to occur at the interface between the light metal base material portion and the composite material portion when the temperature of the metal sintered body composite material is rapidly changed.
【０００５】本発明は上記した実情に鑑みなされたもの
であり、請求項１の課題は、両者の熱膨張率の差を規定
することにより、焼き入れ等の急冷処理の様に温度変化
が急激な場合において、複合材料部と軽金属母材部との
界面での亀裂を抑えるのに有利な金属焼結体複合材料を
提供することにある。請求項２の課題は、上記課題に加
えて、軽金属が含浸、固化されて複合材料部を構成する
多孔質金属焼結体を積層構造とすることにより、熱膨張
率の差を小さく規定して耐亀裂性を確保しつつ、複合材
料部を摺動部材として一層適する様にした金属焼結体複
合材料を提供することにある。The present invention has been made in view of the above situation, and the object of claim 1 is to define the difference in the coefficient of thermal expansion between the two so that the temperature change abruptly as in the quenching process such as quenching. In other cases, it is an object of the present invention to provide a metal-sintered composite material that is advantageous for suppressing cracks at the interface between the composite material portion and the light metal base material portion. In addition to the above problems, the problem of claim 2 is that the difference in the coefficient of thermal expansion is specified to be small by forming a porous metal sintered body that is impregnated and solidified with a light metal to form a composite material portion, into a laminated structure. Another object of the present invention is to provide a sintered metal composite material in which the composite material portion is more suitable as a sliding member while ensuring crack resistance.
【０００６】[0006]
【課題を解決するための手段】請求項１に係る金属焼結
体複合材料は、多孔質金属焼結体の気孔部分に軽金属を
含浸、固化して形成した複合材料部と、複合材料部を被
覆すると共に該複合材料部を構成する軽金属と同材質の
軽金属母材部とからなり、複合材料部と軽金属母材部と
の界面において両者の熱膨張率の差を５×１０-6／℃以
下としたことを特徴としたものである。According to a first aspect of the present invention, there is provided a composite material portion comprising a composite material portion formed by impregnating and solidifying a light metal in a pore portion of a porous metal sintered body, and a composite material portion. It is composed of a light metal base material part which is the same material as the light metal which is coated and constitutes the composite material part, and the difference in the coefficient of thermal expansion between the composite material part and the light metal base material part is 5 × 10 −6 / ° C. It is characterized by the following.
【０００７】請求項２に係る金属焼結体複合材料は、請
求項１において、軽金属が含浸、固化されて複合材料部
を構成する多孔質金属焼結体は、軽金属母材部との熱膨
張率の差を小さくする母材側焼結体層と、母材側焼結体
層と一体をなすと共に摺動面を形成する摺動側焼結体層
とを備え、摺動側焼結体層は、母材側焼結体層よりも摺
動特性が優れていることを特徴とするものである。The metal sintered body composite material according to claim 2 is the porous metal sintered body according to claim 1, which is impregnated with light metal and solidified to form a composite material portion, and the porous metal sintered body has a thermal expansion coefficient with the light metal base material portion. The sliding side sintered body is provided with a base material side sintered body layer that reduces the difference in the ratio and a sliding side sintered body layer that is integral with the base material side sintered body layer and forms a sliding surface. The layer is characterized in that it has better sliding characteristics than the base material side sintered body layer.
【０００８】[0008]
【作用及び発明の効果】請求項１によれば、複合材料部
と軽金属母材部との界面において両者の熱膨張率の差は
５×１０-6／℃以下とされている。そのため急冷処理等
の様に温度が急激に変化したとしても、複合材料部と軽
金属母材部との界面において亀裂抑制性を高め得る。According to the present invention, the difference in the coefficient of thermal expansion between the composite material portion and the light metal base material portion is 5 × 10 −6 / ° C. or less. Therefore, even if the temperature changes abruptly as in the case of rapid cooling treatment or the like, the crack suppressing property can be enhanced at the interface between the composite material portion and the light metal base material portion.
【０００９】熱膨張率の差が小さいため、急冷処理に伴
い発生する熱収縮に起因するせん断力の発生の度合が減
少するためと推察される。よって本発明に係る金属焼結
体複合材料によれば、両者の界面における耐亀裂性は高
まり、耐久性や長寿命化に有利である。請求項２によれ
ば、複合材料部を構成する多孔質金属焼結体は、軽金属
母材部との熱膨張率の差を小さくする母材側焼結体層
と、摺動面を形成する摺動側焼結体層とを備えており、
いわば積層構造とされている。そして、摺動面を形成す
る摺動側焼結体層は、母材側焼結体層よりも摺動特性が
優れている。It is presumed that the difference in the coefficient of thermal expansion is small, so that the degree of generation of shearing force due to the thermal contraction generated by the rapid cooling treatment is reduced. Therefore, according to the metal sintered body composite material of the present invention, the crack resistance at the interface between the two is increased, which is advantageous for durability and long life. According to the second aspect, the porous metal sintered body forming the composite material portion forms the base material side sintered body layer for reducing the difference in coefficient of thermal expansion from the light metal base material portion, and the sliding surface. Equipped with a sliding side sintered body layer,
It is, so to speak, a laminated structure. The sliding-side sintered body layer forming the sliding surface has better sliding characteristics than the base material-side sintered body layer.
【００１０】そのため請求項２によれば、複合材料部と
軽金属母材部との熱膨張率の差を小さくして界面におけ
る耐亀裂性を確保しつつ、摺動面における摺動特性（例
えば耐摩耗性、強度、弾性率、靭性など）を確保するの
に有利であり、摺動面の耐久性や長寿命化に有利であ
る。Therefore, according to the second aspect, the difference in the coefficient of thermal expansion between the composite material portion and the light metal base material portion is reduced to secure crack resistance at the interface, and at the same time, sliding characteristics (for example, resistance to resistance on the sliding surface) Abrasion resistance, strength, elastic modulus, toughness, etc.), and durability and long life of the sliding surface.
【００１１】[0011]
【実施例】本発明の実施例について、実施例に至る経緯
と共に説明する。図１は本実施例に係る金属焼結体複合
材料の断面を模式的に示す。金属焼結体複合材料は、複
合材料部２と、軽金属母材部としてのアルミ合金部３と
で形成されている。複合材料部２は、気孔部分をもつ格
子構造を備えたスケルトン状の多孔質金属焼結体１を用
い、これに軽金属としてのアルミ合金の溶湯を含浸し、
固化して形成されている。EXAMPLES Examples of the present invention will be described together with the background to the examples. FIG. 1 schematically shows a cross section of a metal sintered body composite material according to this example. The metal sintered body composite material is composed of a composite material part 2 and an aluminum alloy part 3 as a light metal base material part. The composite material part 2 uses a skeleton-shaped porous metal sintered body 1 having a lattice structure having pores, and impregnated with a molten aluminum alloy as a light metal,
It is formed by solidification.
【００１２】アルミ合金部３は、複合材料部２を被覆す
ると共に複合材料部２を構成するアルミ合金と同材質の
アルミ合金で形成されている。多孔質金属焼結体１は複
合材料部２のアルミ合金を強化する強化材を構成するも
のである。多孔質金属焼結体１を構成する材料として
は、その強度、弾性率、耐摩耗性等の特性及びコストな
どから、鉄系材料を選択することが好ましい。従って鉄
系粉末を焼結して構成できる。鉄系粉末としては炭素鋼
粉末、鋳鉄系粉末、合金鋼粉末（例えばＳＫＤ系、ＳＫ
Ｈ系等）などを採用できる。The aluminum alloy part 3 is formed of the same aluminum alloy as the aluminum alloy which covers the composite material part 2 and constitutes the composite material part 2. The porous metal sintered body 1 constitutes a reinforcing material that strengthens the aluminum alloy of the composite material portion 2. As a material forming the porous metal sintered body 1, it is preferable to select an iron-based material in view of its properties such as strength, elastic modulus, wear resistance, and cost. Therefore, it can be formed by sintering iron-based powder. The iron-based powder includes carbon steel powder, cast iron-based powder, alloy steel powder (for example, SKD-based, SK
H series etc.) can be adopted.
【００１３】本実施例では前述の様に、気孔部分をもつ
格子構造を備えたスケルトン状の多孔質金属焼結体１を
用い、多孔質金属焼結体１の気孔部分にアルミ合金の溶
湯を高圧鋳造法にて含浸させ、固化させ、一体的に複合
化する。これにより金属焼結体複合材料を製造する。こ
の様にして製造した金属焼結体複合材料に対して、溶体
化→焼き入れ→時効処理を順に実施する。この場合、焼
き入れ時に複合材料部２とアルミ合金部３との界面にお
いて亀裂が発生し易い。In this embodiment, as described above, the skeleton-shaped porous metal sintered body 1 having the lattice structure having the pores is used, and the molten aluminum alloy is applied to the pores of the porous metal sintered body 1. It is impregnated by a high-pressure casting method, solidified, and integrally compounded. Thereby, a metal sintered body composite material is manufactured. The metal-sintered composite material thus produced is subjected to solution treatment, quenching, and aging treatment in this order. In this case, cracks are likely to occur at the interface between the composite material portion 2 and the aluminum alloy portion 3 during quenching.
【００１４】鉄系材料は一般的に熱膨張率が１１×１０
-6／℃程度である。複合材料部２のうち鉄系の多孔質金
属焼結体１が占める体積率を６５％とした場合には、ア
ルミ合金（ＪＩＳ ＡＣ８Ａ、熱膨張率：２０×１０-6
／℃）の溶湯を含浸し、固化させて複合材料部２を形成
すると、その複合材料部２の熱膨張率は基本的には約１
４×１０-6／℃となる。従って複合材料部２とアルミ合
金部３との熱膨張率の差は、基本的には６×１０-6／℃
（＝２０×１０-6／℃−１４×１０-6／℃）となり、大
きくなる。Iron-based materials generally have a coefficient of thermal expansion of 11 × 10.
It is about -6 / ° C. When the volume ratio of the iron-based porous metal sintered body 1 in the composite material part 2 is set to 65%, an aluminum alloy (JIS AC8A, coefficient of thermal expansion: 20 × 10 −6) is used.
When the composite material part 2 is formed by impregnating it with a molten metal (/ ° C.) and solidifying it, the coefficient of thermal expansion of the composite material part 2 is basically about 1.
It becomes 4 × 10 −6 / ° C. Therefore, the difference in the coefficient of thermal expansion between the composite material part 2 and the aluminum alloy part 3 is basically 6 × 10 -6 / ° C.
(= 20 × 10 −6 / ° C.−14 × 10 −6 / ° C.), which is large.
【００１５】なお体積率とは、複合材料部２の体積をＶ
１とし、複合材料部２のうち多孔質金属焼結体部分が占
める体積をＶ２としたとき、｛（Ｖ２／Ｖ１）×１０
０｝％の意味である。この様に鉄系の多孔質金属焼結体
１を用いた複合材料部２の熱膨張率とアルミ合金部３の
熱膨張率との差が大きいため、焼き入れ等の急冷処理に
おいて急激な温度変化で、複合材料部２とアルミ合金部
３との界面において急激にせん断力が働いて、亀裂が発
生し易くなるものと推察される。The volume ratio means the volume of the composite material part 2 by V
1, and the volume occupied by the porous metal sintered body portion in the composite material portion 2 is V2, {(V2 / V1) × 10
It means 0}%. Since the difference between the coefficient of thermal expansion of the composite material part 2 using the iron-based porous metal sintered body 1 and the coefficient of thermal expansion of the aluminum alloy part 3 is large as described above, a rapid temperature rise during quenching treatment such as quenching occurs. It is speculated that due to the change, a shearing force suddenly acts on the interface between the composite material part 2 and the aluminum alloy part 3 to easily cause cracks.
【００１６】なお上記したアルミ合金（ＪＩＳ ＡＣ８
Ａ）は、ＪＩＳ規格上、重量％でＳｉが１１．０〜１
３．０％、Ｍｇが０．７〜１．３％、Ｃｕが０．８〜
１．３％、Ｎｉが１．０〜２．５％、Ｆｅが０．８％以
下、Ｚｎが０．１％以下と規定されている。一方、他の
形態として、オーステナイト系ステンレス鋼であるＳＵ
Ｓ３０４の金属粉末を圧粉して焼結した格子構造をもつ
スケルトン状の多孔質金属焼結体１を用い、その多孔質
金属焼結体１の気孔部分にアルミ合金の溶湯を含浸、固
化させて複合化し、複合材料部２とアルミ合金部３とを
備えた金属焼結体複合材料を形成した。この複合材料部
２に占める多孔質金属焼結体１の体積率は７０％であ
る。The above aluminum alloy (JIS AC8
A) is 11.0 to 1% by weight of Si according to the JIS standard.
3.0%, Mg 0.7-1.3%, Cu 0.8-
It is specified that 1.3%, Ni is 1.0 to 2.5%, Fe is 0.8% or less, and Zn is 0.1% or less. On the other hand, as another form, SU which is an austenitic stainless steel is used.
A skeleton-shaped porous metal sintered body 1 having a lattice structure obtained by compacting and sintering the metal powder of S304 is used, and pores of the porous metal sintered body 1 are impregnated with a molten aluminum alloy and solidified. And composited to form a metal sintered body composite material including the composite material portion 2 and the aluminum alloy portion 3. The volume ratio of the porous metal sintered body 1 in the composite material part 2 is 70%.
【００１７】この金属焼結体複合材料を焼き入れしたと
ころ、複合材料部２とアルミ合金部３との界面において
亀裂は発生しなかった。この場合、ＳＵＳ３０４製の多
孔質金属焼結体１にアルミ合金を含浸、固化させて形成
した複合材料部２は、熱膨張率が基本的には約１８×１
０-6／℃である。従って熱膨張率がアルミ合金部３の熱
膨張率（基本的には２０×１０-6／℃）に近く、両者の
熱膨張率の差は小さくなり、従って急冷処理の際にそれ
ほど大きなせん断力が界面に生じないため、亀裂が発生
しなかったものと推察される。When this metal sintered body composite material was quenched, no cracks were generated at the interface between the composite material portion 2 and the aluminum alloy portion 3. In this case, the composite material part 2 formed by impregnating and solidifying the porous metal sintered body 1 made of SUS304 with an aluminum alloy has a coefficient of thermal expansion of basically about 18 × 1.
It is 0 -6 / ° C. Therefore, the coefficient of thermal expansion is close to the coefficient of thermal expansion of the aluminum alloy part 3 (basically 20 × 10 −6 / ° C.), and the difference in coefficient of thermal expansion between the two becomes small, so that a large shearing force is applied during quenching. It is presumed that cracks did not occur because the cracks did not occur at the interface.
【００１８】上記検討の後、各種複合材料について同様
の検討をした結果、複合材料部２の熱膨張率とアルミ合
金部３の熱膨張率との差を５×１０-6／℃以下とすれ
ば、焼き入れ等の急冷処理時に複合材料部２とアルミ合
金部３との界面において亀裂抑止効果が高くなり、亀裂
が発生しないことがわかった。ところで鉄系材料は一般
的に熱膨張率がアルミ系よりもかなり小さく、前述の様
に１１×１０-6／℃程度であり、アルミ系の熱膨張率と
の差は大きい。高い熱膨張率、即ちアルミ合金部３に近
い熱膨張率をもつ鉄系材料は、オーステナイト系ステン
レス鋼やマンガン鋼等に限られている。しかしこのよう
なオーステナイト系ステンレス鋼やマンガン鋼等の材料
のみでは、優れた摺動特性を備えた金属焼結体複合材料
を製造するには不利である。After the above examination, the same examination was conducted on various composite materials. As a result, it was found that the difference between the coefficient of thermal expansion of the composite material portion 2 and the coefficient of thermal expansion of the aluminum alloy portion 3 was 5 × 10 −6 / ° C. or less. For example, it has been found that the effect of suppressing cracks is enhanced at the interface between the composite material part 2 and the aluminum alloy part 3 during quenching such as quenching, and cracks do not occur. By the way, an iron-based material generally has a coefficient of thermal expansion much smaller than that of an aluminum-based material, and is about 11 × 10 −6 / ° C. as described above, which is a large difference from the coefficient of thermal expansion of an aluminum-based material. Iron-based materials having a high coefficient of thermal expansion, that is, a coefficient of thermal expansion close to that of the aluminum alloy portion 3 are limited to austenitic stainless steel, manganese steel, and the like. However, such materials such as austenitic stainless steel and manganese steel alone are disadvantageous in producing a metal sintered body composite material having excellent sliding properties.
【００１９】そこで本発明者は、複合材料部２のうちア
ルミ合金部３に直接接触する度合が大きな領域は、アル
ミ合金部３との熱膨張率の差を５×１０-6／℃以下と小
さくし、且つ、複合材料部２のうち摺動面を形成する領
域は、アルミ合金部３との熱膨張率の差が大きいもの
の、つまり５×１０-6／℃を越えるかもしれないが、摺
動特性に優れた材料とすれば良いことに、着目した。Therefore, the inventor of the present invention has found that a region of the composite material portion 2 having a large degree of direct contact with the aluminum alloy portion 3 has a difference in coefficient of thermal expansion from the aluminum alloy portion 3 of 5 × 10 −6 / ° C. or less. Although the area of the composite material portion 2 which forms the sliding surface is made smaller, the difference in thermal expansion coefficient with the aluminum alloy portion 3 is large, that is, it may exceed 5 × 10 −6 / ° C., We paid attention to the fact that a material with excellent sliding properties should be used.
【００２０】この様な特性を備えた金属焼結体複合材料
は、多層構造の多孔質金属焼結体を用い、これにアルミ
合金の溶湯を含浸、固化させて形成することにより実現
できる。この例を図２に示す。図２に示す様に、アルミ
合金が含浸される多孔質金属焼結体４は三層の積層構造
であり、外側の層を構成する母材側焼結体層としての第
１層４１と、同じく外側の層を構成する母材側焼結体層
としての第３層４３と、第１層４１、第３層４３に挟ま
れた摺動側焼結体層としての第２層４２とを備えてい
る。ここで第１層４１、第４層４３にアルミ合金を含浸
固化させた複合材料部分の熱膨張率は、アルミ合金部３
の熱膨張率との差を小さく設定し、つまり５×１０-6／
℃以下に設定する。The metal sintered body composite material having such characteristics can be realized by using a porous metal sintered body having a multilayer structure and impregnating it with a molten aluminum alloy to solidify it. An example of this is shown in FIG. As shown in FIG. 2, the aluminum alloy-impregnated porous metal sintered body 4 has a three-layer laminated structure, and includes a first layer 41 as a base material side sintered body layer that constitutes an outer layer, Similarly, a third layer 43 as a base material side sintered body layer that constitutes the outer layer and a second layer 42 as a sliding side sintered body layer sandwiched between the first layer 41 and the third layer 43 are provided. I have it. Here, the coefficient of thermal expansion of the composite material portion obtained by impregnating and solidifying the first layer 41 and the fourth layer 43 with an aluminum alloy is
The difference from the coefficient of thermal expansion is set small, that is, 5 × 10 -6 /
Set below ℃.
【００２１】第２層４２にアルミ合金を含浸固化させた
複合材料部分は、摺動面を形成するものである。従って
第２層４２は、摺動特性（一般的には耐摩耗性、強度、
弾性率及び靭性等の性質）が第１層４１、第３層４３よ
りも優れている様に設定されるている。 （試験例） ＜試験例１＞表１は本試験例で用いる供試粉末を示す。
表１に示す粉末ａは耐熱系高合金鋼であるＳＫＤ６１相
当粉末（粒径：２０〜１８０μｍ、水アトマイズ法）、
粉末ｂはオーステナイト系ステンレス鋼であるＳＵＳ３
０４相当粉末（粒径：２０〜１８０μｍ、水アトマイズ
法）、粉末ｃはマンガン鋼粉末（粒径：２０〜１８０μ
ｍ、水アトマイズ法）、粉末ｄはセラミックス系硬質粒
子粉末であるムライト粉末（粒径：１０〜４５μｍ、粉
砕法）である。The composite material portion obtained by impregnating and solidifying the second layer 42 with an aluminum alloy forms a sliding surface. Therefore, the second layer 42 has a sliding property (generally, wear resistance, strength,
Properties such as elastic modulus and toughness) are set to be superior to those of the first layer 41 and the third layer 43. (Test Example) <Test Example 1> Table 1 shows the test powders used in this test example.
Powder a shown in Table 1 is a powder corresponding to SKD61 which is a heat resistant high alloy steel (particle size: 20 to 180 μm, water atomizing method),
Powder b is SUS3 which is austenitic stainless steel
04 equivalent powder (particle size: 20 to 180 μm, water atomizing method), powder c is manganese steel powder (particle size: 20 to 180 μm)
m, water atomizing method), and the powder d is mullite powder (particle diameter: 10 to 45 μm, pulverizing method) which is a ceramic-based hard particle powder.
【００２２】表２は本試験例で製造した試験片Ａ、Ｂ、
Ｃを示す。表２から理解できる様に、試験片Ａによれ
ば、多孔質金属焼結体４は前述の様に第１層４１と第２
層４２と第３層４３との積層構造されている。第１層４
１は体積率が６０％に設定されており、粉末ｂで形成さ
れている。第２層４２は体積率が６０％に設定されてお
り、粉末ａで形成されている。第３層４３は体積率が６
０％に設定されており、粉末ｂで形成されている。Table 2 shows test pieces A, B, manufactured in this test example.
C is shown. As can be understood from Table 2, according to the test piece A, the porous metal sintered body 4 has the first layer 41 and the second layer 41 as described above.
The layer 42 and the third layer 43 are laminated. First layer 4
In No. 1, the volume ratio is set to 60%, and it is formed of powder b. The second layer 42 is set to have a volume ratio of 60% and is formed of powder a. The volume ratio of the third layer 43 is 6
It is set to 0% and is formed of powder b.
【００２３】表２から理解できる様に、試験片Ｂによれ
ば、試験片Ａと同様に多孔質金属焼結体４は第１層４１
と第２層４２と第３層４３との積層構造されている。第
１層４１は体積率が６０％に設定されており、体積率４
０％に相当する粉末ａと、体積率２０％に相当する粉末
ｂとで形成されている。なお、粉末ａが体積率４０％に
相当するとは、第１層４１に係る複合材料部分の体積を
１００％としたとき、粉末ａで形成された焼結体部分が
体積で４０％を占めるという意味である。As can be understood from Table 2, according to the test piece B, the porous metal sintered body 4 is similar to the test piece A in the first layer 41.
And a second layer 42 and a third layer 43 are laminated. The first layer 41 has a volume ratio of 60% and a volume ratio of 4%.
It is formed of a powder a corresponding to 0% and a powder b corresponding to a volume ratio of 20%. In addition, that the powder a corresponds to a volume ratio of 40% means that, when the volume of the composite material portion of the first layer 41 is 100%, the sintered body portion formed of the powder a occupies 40% of the volume. Is the meaning.
【００２４】第２層４２は体積率が６０％に設定されて
おり、粉末ａで形成されている。第３層４３は第１層４
１と基本的に同様であり、体積率が６０％に設定されて
おり、体積率４０％に相当する粉末ａと、体積率２０％
に相当する粉末ｂとで形成されている。表２から理解で
きる様に、試験片Ｃよれば、多孔質金属焼結体は１層で
あり、体積率が６０％に設定されており、粉末ａで形成
されている。The volume ratio of the second layer 42 is set to 60%, and it is made of powder a. Third layer 43 is first layer 4
The volume ratio is set to 60%, the powder a corresponds to a volume ratio of 40%, and the volume ratio is 20%.
And powder b corresponding to As can be understood from Table 2, according to the test piece C, the porous metal sintered body has one layer, the volume ratio is set to 60%, and the powder a is formed.
【００２５】そして、表１に示した所定の金属粉末を用
い、潤滑剤としてのステアリン酸亜鉛を金属粉末に対し
て１ｗｔ％を秤量し、それらをＶ型混合機にて混合し
た。次に、３０ｍｍ×４０ｍｍの大きさのキャビティを
備えた金型に、所定量の粉末を入れ、加圧することによ
り、圧粉体（３０ｍｍ×４０ｍｍ×厚さ１０ｍｍ）を作
成した。Then, using the prescribed metal powders shown in Table 1, 1 wt% of zinc stearate as a lubricant was weighed with respect to the metal powders, and they were mixed in a V-type mixer. Next, a powder (30 mm × 40 mm × thickness 10 mm) was prepared by putting a predetermined amount of the powder into a mold provided with a cavity of 30 mm × 40 mm and pressurizing the powder.
【００２６】なお試験例Ａ、試験例Ｂに係る３層構造の
圧粉体は、金型のキャビティに順次金属粉末を投入して
加圧することにより製作した。このとき第１層の厚さ、
第３層の厚さをそれぞれ２ｍｍ、第２層の厚さを６ｍｍ
となるように、粉末の投入量をコントロールした。そし
て試験例Ａ〜試験例Ｃに係る圧粉体を真空焼結炉にてそ
れぞれ焼結した。即ち、真空焼結炉にて７００℃で３０
分間保持し、ステアリン酸亜鉛を揮発させ、その後に、
１１００℃で３０分間焼結し、以て格子構造をもつスケ
ルトン状の試験例Ａ〜試験例Ｃに係る多孔質金属焼結体
を得た。The green compacts of the three-layer structure according to Test Examples A and B were manufactured by sequentially introducing metal powder into the cavity of the mold and applying pressure. At this time, the thickness of the first layer,
The thickness of the third layer is 2 mm, and the thickness of the second layer is 6 mm.
The amount of powder input was controlled so that Then, the green compacts according to Test Example A to Test Example C were each sintered in a vacuum sintering furnace. That is, at 30 ° C. in a vacuum sintering furnace at 700 ° C.
Hold for minutes to volatilize zinc stearate, then
Sintering was performed at 1100 ° C. for 30 minutes to obtain skeleton-shaped porous metal sintered bodies according to Test Examples A to C having a lattice structure.
【００２７】焼結した後は、１００℃／分の冷却速度と
なるように窒素ガスで各多孔質金属焼結体を強制冷却し
た。つまり気体冷却した。なお窒素ガスを用いたのは多
孔質金属焼結体の酸化防止などを考慮したからである。
この場合、多孔質金属焼結体を水冷や油冷することは好
ましくない。多孔質金属焼結体の気孔内部に水分や油分
を残留させ易く、アルミ合金の溶湯を含浸して複合化し
た際に水分や油分が蒸散してガス欠陥を誘発し易いから
である。After sintering, each porous metal sintered body was forcibly cooled with nitrogen gas so that the cooling rate was 100 ° C./min. That is, it was gas cooled. The reason why nitrogen gas is used is that it takes into consideration the oxidation prevention of the porous metal sintered body.
In this case, it is not preferable to cool the porous metal sintered body with water or oil. This is because it is easy for water and oil to remain inside the pores of the porous metal sintered body, and when the molten aluminum alloy is impregnated to form a composite, the water and oil easily evaporate and induce gas defects.
【００２８】次に、試験例Ａ〜試験例Ｃに係る多孔質金
属焼結体を、それぞれ２００℃において大気雰囲気で３
０分間予熱した。その後、予熱した各多孔質金属焼結体
を高圧鋳造金型のキャビティの所定位置に配置し、７５
０℃のアルミ合金（ＪＩＳＡＣ８Ａ）の溶湯をキャビテ
ィに注ぎ、直ちに１００ＭＰａの加圧力で加圧した。こ
れによりスケルトン状の多孔質金属焼結体の気孔部分に
アルミ合金の溶湯を含浸させた。アルミ合金の固化によ
り両者が一体化して金属焼結体複合材料（φ１００×５
０ｍｍ）が形成される。これを金型から取り出した。こ
の様にして製造した金属焼結体複合材料の断面を図３に
示す。Next, the porous metal sintered bodies according to Test Example A to Test Example C were each subjected to 3 atmosphere at 200 ° C. in an air atmosphere.
Preheated for 0 minutes. Then, each preheated porous metal sintered body is placed at a predetermined position in the cavity of the high-pressure casting die,
A molten aluminum alloy (JIS AC8A) at 0 ° C. was poured into the cavity and immediately pressurized with a pressure of 100 MPa. As a result, the molten aluminum alloy was impregnated into the pores of the skeleton-shaped porous metal sintered body. By solidifying the aluminum alloy, the two are integrated and the sintered metal composite material (φ100 × 5
0 mm) is formed. This was taken out of the mold. A cross section of the metal-sintered composite material produced in this manner is shown in FIG.
【００２９】この様にして製造した金属焼結体複合材料
を用い、大気中において５００℃×３時間の条件で加熱
保持して溶体化処理した後、約７０℃の温水に焼き入れ
した。その後、その金属焼結体複合材料を大気中におい
て２２０℃×３時間の条件で加熱保持して時効処理を実
施した（ＡＳＴＭ：Ｔ７処理）。この時効処理により複
合材料部２のアルミ部分、アルミ合金部３のアルミ部分
は強化、安定化される。Using the metal-sintered composite material produced in this manner, the solution was heat-treated in the atmosphere at 500 ° C. for 3 hours for solution treatment, and then quenched in warm water at about 70 ° C. Then, the metal-sintered composite material was heated and held in the atmosphere at 220 ° C. for 3 hours to perform an aging treatment (ASTM: T7 treatment). By this aging treatment, the aluminum part of the composite material part 2 and the aluminum part of the aluminum alloy part 3 are strengthened and stabilized.
【００３０】この様にして得られた金属焼結体複合材料
を複合材料部２が露出するように半分に切断した。そし
て、その切断面をカラーチェックをして複合材料部２と
アルミ合金部３との界面における亀裂発生状況を調査し
た。その結果を表２において○×で示した。表２から理
解できる様に、試験片Ｃにおいては、亀裂発生の評価は
×であった。即ち、複合材料部２とアルミ合金部３との
界面において赤色の発色がみられ、亀裂が発生していた
ことが確認された。一方、三層積層構造の多孔質金属焼
結体４が採用されている試験片Ａにおいては、複合材料
部２とアルミ合金部３との界面には、全く赤色の発色が
見られず、亀裂が発生していないことが確認できた。The metal sintered body composite material thus obtained was cut in half so that the composite material part 2 was exposed. Then, the cut surface was color-checked to investigate the crack generation state at the interface between the composite material part 2 and the aluminum alloy part 3. The results are shown by ◯ × in Table 2. As can be understood from Table 2, in the test piece C, the crack generation was evaluated as x. That is, it was confirmed that red coloration was observed at the interface between the composite material part 2 and the aluminum alloy part 3 and a crack had occurred. On the other hand, in the test piece A in which the porous metal sintered body 4 having the three-layer laminated structure is adopted, no red coloring is observed at the interface between the composite material portion 2 and the aluminum alloy portion 3, and cracks are generated. It was confirmed that the above did not occur.
【００３１】また三層積層構造の多孔質金属焼結体４が
採用されている試験片Ｂにおいても、試験例Ａと同様
に、複合材料部２とアルミ合金部３との界面には、全く
赤色の発色が見られず、亀裂が発生していないことが確
認できた。上記試験例Ａ〜試験例Ｃに使用された複合材
料部２の各層と同じ材質の熱膨張測定試験片を形成し、
その熱膨張率を測定した。同様にアルミ合金部３と同じ
材質の熱膨張測定試験片を形成し、その熱膨張率も測定
した。その結果も表２に示す。Also in the test piece B in which the porous metal sintered body 4 having the three-layer laminated structure is adopted, as in the test example A, the interface between the composite material portion 2 and the aluminum alloy portion 3 is completely absent. It was confirmed that no red color was observed and no cracks were generated. A thermal expansion test piece of the same material as each layer of the composite material part 2 used in the above-mentioned Test Examples A to C was formed,
The coefficient of thermal expansion was measured. Similarly, a thermal expansion measurement test piece of the same material as the aluminum alloy part 3 was formed, and the thermal expansion coefficient thereof was also measured. The results are also shown in Table 2.
【００３２】表２から理解できる様に、試験片Ａによれ
ば、オーステナイト系ステンレス鋼粉末を基材とする第
１層４１に係る複合材料部分は熱膨張率が１８．４×１
０-6／℃である。ＳＫＤ６１相当粉末を基材とする第２
層４２に係る複合材料部分は熱膨張率が１４．５×１０
-6／℃である。第３層４３に係る複合材料部分は第１層
４１の場合と同様に熱膨張率が１８．４×１０-6／℃で
ある。なお、熱膨張率は常温領域〜４００℃の温度領域
において測定したものである。As can be seen from Table 2, according to the test piece A, the composite material portion of the first layer 41 based on austenitic stainless steel powder has a coefficient of thermal expansion of 18.4 × 1.
It is 0 -6 / ° C. The second which uses powder corresponding to SKD61 as the base material
The composite material portion of layer 42 has a coefficient of thermal expansion of 14.5 x 10
-6 / ° C. The composite material portion of the third layer 43 has a coefficient of thermal expansion of 18.4 × 10 −6 / ° C. as in the case of the first layer 41. The coefficient of thermal expansion is measured in the temperature range of room temperature to 400 ° C.
【００３３】表２から理解できる様に、試験片Ｂによれ
ば、第１層４１に係る複合材料部分は熱膨張率が１５．
４×１０-6／℃であり、第２層４２に係る複合材料部分
は熱膨張率が１４．５×１０-6／℃であり、第３層４３
に係る複合材料部分は熱膨張率が１５．４×１０-6／℃
であった。ＳＫＤ６１相当粉末のみを基材とする試験片
Ｃは、熱膨張率が１４．５×１０-6／℃であった。As can be seen from Table 2, according to the test piece B, the composite material portion of the first layer 41 has a coefficient of thermal expansion of 15.
4 × 10 −6 / ° C., the composite material portion of the second layer 42 has a coefficient of thermal expansion of 14.5 × 10 −6 / ° C., and the third layer 43
The coefficient of thermal expansion of the composite material part related to 15.4 × 10 -6 / ° C
Met. The thermal expansion coefficient of the test piece C containing only the powder corresponding to SKD61 as a base material was 14.5 × 10 −6 / ° C.
【００３４】前述した様に試験片Ｃにおいて亀裂が発生
したのは、複合材料部２とアルミ合金部３との熱膨張率
の差が５．５×１０-6／℃（＝２０．０×１０-6−１
４．５×１０-6）と大きく、急冷時においてせん断力が
作用して界面において亀裂が発生したものと推察され
る。また試験片Ａによれば、複合材料部２の第１層４１
に係る複合材料部分、第３層４１に係る複合材料部分と
アルミ合金部３との熱膨張率の差が１．６×１０-6／℃
（＝２０．０×１０-6−１８．４×１０-6）である。ま
た試験片Ｂによれば、４．６×１０-6／℃（＝２０．０
×１０-6−１５．４×１０-6）と小さな値であり、熱膨
張率の差が５．０×１０-6／℃以下であるため、界面に
おいて亀裂は発生しなかった。As described above, cracks were generated in the test piece C because the difference in coefficient of thermal expansion between the composite material part 2 and the aluminum alloy part 3 was 5.5 × 10 −6 / ° C. (= 20.0 ×). 10 -6 -1
It is as large as 4.5 × 10 -6 ), and it is presumed that a shearing force was applied during the rapid cooling to cause cracks at the interface. Further, according to the test piece A, the first layer 41 of the composite material part 2 is
The difference in the coefficient of thermal expansion between the aluminum alloy part 3 and the composite material part of the third layer 41, the composite material part of the third layer 41 is 1.6 × 10 −6 / ° C.
(= 20.0 × 10 -6 -18.4 × 10 -6 ). According to the test piece B, 4.6 × 10 −6 / ° C. (= 20.0
It was a small value of × 10 -6 -15.4 × 10 -6 ), and the difference in the coefficient of thermal expansion was 5.0 × 10 -6 / ° C or less, so no crack was generated at the interface.
【００３５】以上の結果を勘案すれば、複合材料部２と
アルミ合金部３との熱膨張差が５×１０-6／℃以下であ
れば、焼き入れ時において界面の亀裂の発生を防止でき
ることが分かる。Considering the above results, if the difference in thermal expansion between the composite material part 2 and the aluminum alloy part 3 is 5 × 10 −6 / ° C. or less, the occurrence of interface cracks during quenching can be prevented. I understand.
【００３６】[0036]
【表１】 [Table 1]
【００３７】[0037]
【表２】 ＜試験例２＞試験例Ｄとして、図４に示すリング状の多
孔質金属焼結体５（外径９２ｍｍ、内径７２ｍｍ、厚さ
７ｍｍ）を形成した。このリング状の多孔質金属焼結体
は、外側の層を構成する母材側焼結体層としての第１層
５１及び第３層５３（厚み１ｍｍ）と、第１層５１及び
第３層５３に挟まれた摺動側焼結体層としての第２層５
２（厚み５ｍｍ）とで形成されている。[Table 2] <Test Example 2> As Test Example D, a ring-shaped porous metal sintered body 5 (outer diameter 92 mm, inner diameter 72 mm, thickness 7 mm) shown in FIG. 4 was formed. This ring-shaped porous metal sintered body includes a first layer 51 and a third layer 53 (thickness 1 mm) as a base material side sintered body layer that constitutes an outer layer, and a first layer 51 and a third layer. Second layer 5 as a sliding side sintered body layer sandwiched between 53
2 (thickness 5 mm).
【００３８】表３から理解できる様に、試験片Ｄによれ
ば、第１層５１は体積率が６０％に設定されており、体
積率３０％に相当する粉末ａと、体積率３０％に相当す
る粉末ｃとで形成されている。ここで、粉末ａが体積率
３０％に相当するとは、前述同様に、多孔質金属焼結体
の第１層５１に係る複合材料部分を１００体積％とした
とき、そのうち粉末ａからなる焼結体部分が３０％占め
るという意味である。第２層５２は体積率が６３％に設
定されており、体積率６０％に相当する粉末ａと、３％
に相当する粉末ｄとで形成されている。第３層５３は第
１層５１と基本的に同様であり、体積率が６０％に設定
されており、体積率３０％に相当する粉末ａと、体積率
３０％に相当する粉末ｃとで形成されている。As can be understood from Table 3, according to the test piece D, the volume ratio of the first layer 51 is set to 60%, and the powder a corresponding to the volume ratio of 30% and the volume ratio of 30% are obtained. And the corresponding powder c. Here, the powder a corresponds to a volume ratio of 30%, as described above, when the composite material portion of the first layer 51 of the porous metal sintered body is set to 100% by volume, the sintering of the powder a is included. This means that the body part occupies 30%. The volume ratio of the second layer 52 is set to 63%, and powder a corresponding to a volume ratio of 60% and 3% are included.
And powder d corresponding to The third layer 53 is basically similar to the first layer 51 and has a volume ratio of 60%, and includes a powder a corresponding to a volume ratio of 30% and a powder c corresponding to a volume ratio of 30%. Has been formed.
【００３９】第２層５２は表２から理解できる様に、Ｓ
ＫＤ６１相当の粉末とセラミックス硬質粒子を形成する
ムライト粉末（Ｈｖ１４００〜１５００〜１６００程
度）との混合粉末で形成されているため、耐摩耗性、強
度、弾性率の性質が、外第１層５１及び第３層５３より
も優れている。次に、上記した図４に示す多孔質金属焼
結体を３００℃×３０分の条件で予熱した後、ピストン
用高圧鋳造金型のキャビティのうちのトップリング溝位
置に対応するに配置し、そして７６０℃のアルミ合金
（ＪＩＳ ＡＣ８Ａ）溶湯を注ぎ、約１００ＭＰａの加
圧力で加圧し、高圧鋳造によりピストン７（図５参照）
を形成した。図５から理解できる様にピストン７は、ピ
ストン７の主体を形成すると共にピストンヘッド７ｋを
備えた複合材料部２と、この複合材料部２を被覆するア
ルミ合金部３とで構成されている。このピストン７は、
ディーゼル系内燃機関に装備されるものでも良いし、ガ
ソリン系内燃機関に装備されるものでも良い。As can be seen from Table 2, the second layer 52 has S
Since it is formed of a mixed powder of KD61-equivalent powder and mullite powder (Hv1400 to 1500 to 1600) that forms ceramics hard particles, the outer first layer 51 has properties of wear resistance, strength, and elastic modulus. It is superior to the third layer 53. Next, after preheating the above-mentioned porous metal sintered body shown in FIG. 4 under the condition of 300 ° C. × 30 minutes, it is arranged so as to correspond to the position of the top ring groove in the cavity of the high pressure casting die for piston, Then, a molten aluminum alloy (JIS AC8A) at 760 ° C. is poured and pressurized with a pressure of about 100 MPa, and the piston 7 is formed by high pressure casting (see FIG. 5).
Was formed. As can be understood from FIG. 5, the piston 7 is composed of a composite material portion 2 that forms the main body of the piston 7 and is provided with a piston head 7k, and an aluminum alloy portion 3 that covers the composite material portion 2. This piston 7
It may be installed in a diesel internal combustion engine or may be installed in a gasoline internal combustion engine.
【００４０】上記試験片Ｄに使用された複合材料部２と
同じ材質の熱膨張測定試験片を形成し、その熱膨張率を
測定した。その結果も表３に示す。表３から理解できる
様に、試験片Ｄによれば、第１層５１に係る複合材料部
分は熱膨張率が１６．７×１０-6／℃であり、第２層５
２に係る複合材料部分は熱膨張率が１４．１×１０-6／
℃であり、第３層５３に係る複合材料部分は熱膨張率が
１６．７×１０-6／℃であった。A thermal expansion measurement test piece of the same material as the composite material part 2 used for the test piece D was formed, and the thermal expansion coefficient thereof was measured. The results are also shown in Table 3. As can be understood from Table 3, according to the test piece D, the composite material portion related to the first layer 51 has a thermal expansion coefficient of 16.7 × 10 −6 / ° C., and the second layer 5
2 has a coefficient of thermal expansion of 14.1 × 10 −6 /
C. and the composite material portion of the third layer 53 had a coefficient of thermal expansion of 16.7 × 10 −6 / ° C.
【００４１】従って、第１層５１及び第３層５３に係る
複合材料部分の熱膨張率とアルミ合金部３の熱膨張率と
の差は、ピストン７の半径方向つまり矢印Ｘ１方向（図
５参照）において、（２０．０×１０-6／℃）−（１
６．７×１０-6／℃）＝３．３×１０-6／℃となり、か
なり小さい。上記の様に製造したピストン７を用い、前
述同様な条件で溶体化→焼き入れ→時効の熱処理をそれ
ぞれ実施した。そして、第２層５２に係る複合材料部分
を機械加工してリング溝５５を形成した。リング溝５５
を区画する上面５５ｘ、下面５５ｙ及び側面５５ｚが、
ピストンリングとしてのトップリングと摺動する摺動面
を構成する。Therefore, the difference between the coefficient of thermal expansion of the composite material portion relating to the first layer 51 and the third layer 53 and the coefficient of thermal expansion of the aluminum alloy portion 3 is the radial direction of the piston 7, that is, the arrow X1 direction (see FIG. 5). ), (20.0 × 10 −6 / ° C.) − (1
6.7 × 10 -6 /℃)=3.3×10 -6 / ℃ becomes much smaller. Using the piston 7 manufactured as described above, heat treatment of solution-quenching-aging was performed under the same conditions as described above. Then, the composite material portion of the second layer 52 was machined to form the ring groove 55. Ring groove 55
An upper surface 55x, a lower surface 55y, and a side surface 55z that partition the
It forms a sliding surface that slides with the top ring as a piston ring.
【００４２】この様な試験例Ｄにおいても、複合材料部
２とアルミ合金部３との界面における亀裂有無をカラー
チェックにより調査したところ、亀裂の発生は見られな
かった。内燃機関で使用される際には、一般的にピスト
ン７の空洞部７０にはオイル等の冷却剤が吹付けられる
ので、ピストン７の空洞部７０を区画する内面７０ｉは
オイルで冷却される。なお７５はセカンドリングが装備
されるリング溝、７６はオイルリングが装備されるリン
グ溝を示す。リング溝７５、７６はピストン７に直接切
削加工して形成される。In such a test example D as well, when the presence or absence of cracks at the interface between the composite material part 2 and the aluminum alloy part 3 was examined by color check, no cracks were found. When used in an internal combustion engine, a coolant such as oil is generally sprayed onto the hollow portion 70 of the piston 7, so that the inner surface 70i defining the hollow portion 70 of the piston 7 is cooled with oil. Reference numeral 75 denotes a ring groove equipped with a second ring, and 76 denotes a ring groove equipped with an oil ring. The ring grooves 75 and 76 are formed by directly cutting the piston 7.
【００４３】[0043]
【表３】 なお図６に示す形態の様に、第１層５１の内周側と第３
層５３の内周側とを連設した連設層５９を、第１層５１
や第３層５３と同様の材質で形成しても良い。この場合
には、連設層５９の熱膨張率をピストン７のアルミ合金
の熱膨張率に近づけるのに有利である。[Table 3] As in the embodiment shown in FIG. 6, the inner circumference side of the first layer 51 and the third
The continuous layer 59, which is continuous with the inner peripheral side of the layer 53, is used as the first layer 51.
Alternatively, the same material as that of the third layer 53 may be used. In this case, it is advantageous to bring the thermal expansion coefficient of the continuous layer 59 close to that of the aluminum alloy of the piston 7.
【００４４】更に図４に示す多孔質金属焼結体５を構成
する第１層５１、第２層５２、第３層５３を形成する金
属粉末を傾斜組成で金型のキャビティに装填し、第１層
５１、第２層５２、第３層５３を傾斜組成とし、これに
より熱膨張率を傾斜的にピストン７のアルミ合金に近づ
けることにしても良い。 （他の形態） ○上記した例では、アルミ合金を注入して軽金属母材部
を形成しているが、アルミ合金の組成は上記したものに
限定されるものではなく、他の材質のものでもよい。更
にアルミ合金に代えてＭｇ系の合金を注入して軽金属母
材部を形成しても良い。また上記した例では三層構造の
多孔質金属焼結体を採用しているが、これに限らず用途
に応じて２層、４層、５層等でも良い。 ○また、アルミ合金が含浸固化される多孔質金属焼結体
４、５は、本発明者の試験によれば、摺動面における耐
焼付性に大きな影響を与える。そこで、多孔質金属焼結
体４、５の硬度（特に、耐焼付性等の摺動特性が要請さ
れる摺動面を形成する第２層４２、５２の硬度）をマイ
クロビッカース硬度でＨｖ２００〜８００程度にするこ
とが好ましい。Further, the metal powder forming the first layer 51, the second layer 52 and the third layer 53 constituting the porous metal sintered body 5 shown in FIG. The first layer 51, the second layer 52, and the third layer 53 may have a graded composition so that the coefficient of thermal expansion gradually approaches the aluminum alloy of the piston 7. (Other Embodiments) In the above example, the aluminum alloy is injected to form the light metal base material portion, but the composition of the aluminum alloy is not limited to that described above, and other materials may be used. Good. Further, instead of the aluminum alloy, a Mg-based alloy may be injected to form the light metal base material portion. Further, in the above-mentioned example, a porous metal sintered body having a three-layer structure is adopted, but the present invention is not limited to this, and two layers, four layers, five layers or the like may be used depending on the application. The porous metal sintered bodies 4 and 5 in which the aluminum alloy is impregnated and solidified have a great influence on the seizure resistance on the sliding surface according to the test of the present inventors. Therefore, the hardness of the porous metal sintered bodies 4 and 5 (particularly, the hardness of the second layers 42 and 52 forming the sliding surfaces for which sliding characteristics such as seizure resistance are required) is set to Hv 200 to Micro Vickers hardness. It is preferably about 800.
【００４５】この様にすれば、使用温度が高い場合（例
えば２５０〜３００℃）等の様に厳しい環境下で使用さ
れた場合であっても、多孔質金属焼結体４、５の気孔に
含浸したアルミやマグネシウム等の軽金属の硬度が低下
したとしても、スケルトン状の多孔質金属焼結体４、５
の格子構造が良好に維持されるため、軟化した軽金属を
しっかりと保持し、摺動面における焼付を軽減、回避す
ることができる。By doing so, even if the porous metal sintered bodies 4 and 5 are used in a harsh environment such as when the operating temperature is high (for example, 250 to 300 ° C.), the pores of the porous metal sintered bodies 4 and 5 are not removed. Even if the hardness of the impregnated light metal such as aluminum or magnesium decreases, skeleton-shaped porous metal sintered bodies 4, 5
Since the lattice structure of 1 is maintained well, it is possible to firmly hold the softened light metal and reduce or avoid seizure on the sliding surface.
【００４６】ここでＨｖ２００未満では、多孔質金属焼
結体４、５としての強度が充分ではなく、摺動面におい
て軽金属と共に塑性流動し易くなり、焼付による面荒れ
状態が生成され易い。またＨｖ８００を越えると、複合
材料部２の被削性が低下する。なお多孔質金属焼結体
４、５の硬度の上限値及び下限値は、金属焼結体複合材
料の種類、使用温度等の使用環境等に応じて適宜選択さ
れるが、硬度の上限値は例えば７５０、７００、６５
０、６００にでき、硬度の下限値は例えば２５０、３０
０、３５０にできる。If the Hv is less than 200, the strength of the porous metal sintered bodies 4 and 5 is not sufficient, plastic flow easily occurs together with the light metal on the sliding surface, and a surface roughened state due to seizure easily occurs. Further, if it exceeds Hv800, the machinability of the composite material part 2 deteriorates. The upper limit value and the lower limit value of the hardness of the porous metal sintered bodies 4 and 5 are appropriately selected according to the type of the metal sintered body composite material, the use environment such as the use temperature, and the like. For example, 750, 700, 65
It can be set to 0, 600, and the lower limit of hardness is 250, 30
It can be 0,350.
【００４７】この様な多孔質金属焼結体４、５を構成す
る金属粉末としては、前述したＳＫＤ系、ＳＫＨ系、Ｆ
ｅ−Ｍｎ鋼系が挙げられる。 ○複合材料部２に占める多孔質金属焼結体４、５の割合
は、体積率で４５〜８５％が好ましい。多孔質金属焼結
体４、５の格子部分が軽金属を良好に保持するために
は、ある程度の体積率が必要とされるからである。The metal powders that compose such porous metal sintered bodies 4 and 5 are the above-mentioned SKD type, SKH type, and F type.
An e-Mn steel system is mentioned. The proportion of the porous metal sintered bodies 4 and 5 in the composite material part 2 is preferably 45 to 85% by volume. This is because a certain volume ratio is required for the lattice portions of the porous metal sintered bodies 4 and 5 to hold the light metal well.
【００４８】なお金属焼結体複合材料の用途等に応じ
て、多孔質金属焼結体４、５が占める体積率の上限値は
８０％、７５％、７０％にでき、体積率の下限値は５０
％、５５％にできる。 ○上記した多孔質金属焼結体４、５の内部（特に、摺動
特性が要請される摺動面を形成する第２層４２、５２）
に硬質繊維や硬質粒子を含むこともできる。硬質繊維や
硬質粒子はマイクロビッカース硬度でＨｖ２０００以下
のものが好ましい。Ｈｖ２０００を越えると、相手攻撃
性が強すぎ、摺動面から脱落した硬質繊維や硬質粒子が
摺動面に噛みこまれて摺動面を荒らしたりするが、Ｈｖ
２０００以下のものであれば、荒れの程度は抑えられ
る。The upper limit of the volume ratio occupied by the porous metal sintered bodies 4 and 5 can be set to 80%, 75% and 70% depending on the application of the metal sintered body composite material and the lower limit value of the volume ratio. Is 50
%, 55%. The inside of the above-mentioned porous metal sintered bodies 4 and 5 (particularly, the second layers 42 and 52 forming the sliding surface for which sliding characteristics are required)
It is also possible to contain hard fibers and hard particles. The hard fibers and hard particles preferably have a micro Vickers hardness of Hv 2000 or less. If it exceeds Hv2000, the aggressiveness against the opponent is too strong, and the hard fibers and hard particles dropped from the sliding surface are caught in the sliding surface to roughen the sliding surface.
If it is 2000 or less, the degree of roughness can be suppressed.
【００４９】硬質粒子や硬質繊維の硬度の上限値は１９
００、１８００、１７００等にでき、硬度の下限値は４
００、５００、６００等にできる。この様な硬質粒子と
しては上記したムライト粒子の他に、ＦｅＣｒ粒子（Ｈ
ｖ１７００程度）、ＦｅＭｏ粒子（Ｈｖ１４００程
度）、ＦｅＣｒＣ粒子（Ｈｖ８００程度）を採用でき
る。The upper limit of the hardness of hard particles and hard fibers is 19
00, 1800, 1700, etc., and the lower limit of hardness is 4
It can be 00, 500, 600 or the like. As such hard particles, in addition to the above mullite particles, FeCr particles (H
v1700), FeMo particles (Hv1400), and FeCrC particles (Hv800).
【００５０】なお硬質粒子の平均粒径は適宜選択できる
が、３〜５０μｍ程度、特に４〜３０μｍ程度にでき
る。硬質繊維の平均繊維径は適宜選択できるが、０．５
〜１５μｍ程度、特に１〜７μｍ程度にできる。 ○上記した点を考慮し、多孔質金属焼結体４、５を形成
する金属粉末としては、特に摺動面を形成する第２層４
２、５２を形成する金属粉末としては、重量％でＣが
０．１〜８％、Ｃｒが８．０％〜７０．０％を含むもの
を採用できる。金属粉末としては、重量％でＣが０．１
〜３％、Ｃｒが２．０％〜２０．０％、Ｍｏ、Ｖ、Ｗ、
Ｃｏの少なくとも１種が０．３〜３０％を含むものを採
用できる。Although the average particle size of the hard particles can be selected as appropriate, it can be about 3 to 50 μm, especially about 4 to 30 μm. The average fiber diameter of the hard fibers can be appropriately selected, but is 0.5
It can be set to about 15 μm, particularly about 1 to 7 μm. In consideration of the above points, as the metal powder forming the porous metal sintered bodies 4 and 5, especially the second layer 4 forming the sliding surface is used.
As the metal powder forming 2, 52, a metal powder containing C in an amount of 0.1 to 8% and Cr in an amount of 8.0% to 70.0% by weight can be used. As a metal powder, C is 0.1% by weight.
~ 3%, Cr 2.0% ~ 20.0%, Mo, V, W,
At least one kind of Co may be used in an amount of 0.3 to 30%.
【００５１】例えば上記したＳＫＤ６１相当の鉄系粉
末、更にはＳＫＤ１１相当の鉄系粉末を採用できる。な
おＳＫＤ１１の基本組成は、重量％でＣが１．５％、Ｓ
ｉが０．４％、Ｍｎが０．４％、Ｃｒが１２％、Ｍｏが
１％、Ｖが０．８％である。この範囲であれば、金属粉
末の圧粉体を焼結して多孔質金属焼結体４、５を形成し
た後に気体冷却（例えば、窒素ガス等によるガス冷却、
空気冷却）すれば、上記した範囲の硬度が確保され易
く、即ち多孔質金属焼結体４、５の硬度はＨｖ２００〜
８００の領域を確保し易い。従ってその後に６００℃以
上の軽金属の溶湯を含浸固化させても、多孔質金属焼結
体４、５の過剰な軟化はなく、耐焼付性を確保できる。For example, the above-mentioned iron-based powder corresponding to SKD61 and further iron-based powder corresponding to SKD11 can be adopted. The basic composition of SKD11 is 1.5% by weight of C and S
i is 0.4%, Mn is 0.4%, Cr is 12%, Mo is 1%, and V is 0.8%. Within this range, the green compact of the metal powder is sintered to form the porous metal sintered bodies 4 and 5, and then gas cooling (for example, gas cooling with nitrogen gas,
If air-cooled), the hardness within the above range is easily secured, that is, the hardness of the porous metal sintered bodies 4 and 5 is from Hv200 to.
It is easy to secure the area of 800. Therefore, even if the molten metal of 600 ° C. or higher is subsequently impregnated and solidified, the porous metal sintered bodies 4 and 5 are not excessively softened and the seizure resistance can be secured.
【００５２】（付記）上記した実施例から次の技術的思
想も把握できる。 ○母材側焼結体層の一層ぶんの厚みよりも、摺動側焼結
体層の厚みを厚く設定する請求項２に記載の金属焼結体
複合材料。 ○母材側焼結体層と摺動側焼結体層とが積層されてお
り、積層方向と直交する方向の端側に摺動部を形成する
請求項２に記載の金属焼結体複合材料。 ○多孔質金属焼結体はリング形態または平盤形態である
請求項１に記載の金属焼結体複合材料。(Supplementary Note) The following technical idea can be understood from the above-described embodiment. The metal sintered body composite material according to claim 2, wherein the thickness of the sliding side sintered body layer is set to be thicker than the thickness of one layer of the base material side sintered body layer. The metal sintered body composite according to claim 2, wherein the base material side sintered body layer and the sliding side sintered body layer are laminated, and the sliding portion is formed on the end side in the direction orthogonal to the laminating direction. material. The metal sintered body composite material according to claim 1, wherein the porous metal sintered body has a ring shape or a flat plate shape.
【図１】複合材料部をアルミ合金部で被覆した状態の断
面図である。FIG. 1 is a cross-sectional view of a state in which a composite material portion is covered with an aluminum alloy portion.
【図２】複合材料部の強化材を構成する多孔質金属焼結
体の斜視図である。FIG. 2 is a perspective view of a porous metal sintered body that constitutes a reinforcing material of a composite material portion.
【図３】複合材料部をアルミ合金部で被覆した状態の断
面図である。FIG. 3 is a cross-sectional view of a state in which the composite material portion is covered with an aluminum alloy portion.
【図４】複合材料部の強化材を構成する多孔質金属焼結
体の斜視図である。FIG. 4 is a perspective view of a porous metal sintered body that constitutes the reinforcing material of the composite material part.
【図５】複合材料部を備えたピストンの部分断面図であ
る。FIG. 5 is a partial sectional view of a piston provided with a composite material part.
【図６】他の形態に係る複合材料部を備えたピストンの
部分断面図である。FIG. 6 is a partial cross-sectional view of a piston including a composite material portion according to another embodiment.
図中、２は複合材料部、３はアルミ合金部（軽金属母材
部）、４及び５は多孔質金属焼結体、４１及び５１は第
１層（母材側焼結体層）、４２及び５２は第２層（摺動
側焼結体層）、４３及び５３は第３層（母材側焼結体
層）、７はピストンを示す。In the figure, 2 is a composite material part, 3 is an aluminum alloy part (light metal base material part), 4 and 5 are porous metal sintered bodies, 41 and 51 are first layers (base material side sintered body layers), 42 Reference numerals 52 and 52 denote a second layer (sliding side sintered body layer), 43 and 53 denote a third layer (base material side sintered body layer), and 7 denotes a piston.
Claims (2)
浸、固化して形成した複合材料部と、 該複合材料部を被覆すると共に該複合材料部を構成する
軽金属と同材質の軽金属母材部とからなり、 該複合材料部と該軽金属母材部との界面において両者の
熱膨張率の差を５×１０-6／℃以下としたことを特徴と
した金属焼結体複合材料。1. A composite material part formed by impregnating and solidifying a light metal in a pore part of a porous metal sintered body, and a light metal of the same material as the light metal which covers the composite material part and constitutes the composite material part. A sintered metal composite material comprising a base material part and having a difference in coefficient of thermal expansion between the composite material part and the light metal base material part of 5 × 10 −6 / ° C. or less. .
成する多孔質金属焼結体は、 軽金属母材部との熱膨張率の差を小さくする母材側焼結
体層と、該母材側焼結体層と一体をなすと共に摺動面を
形成する摺動側焼結体層とを備え、 該摺動側焼結体層は、該母材側焼結体層よりも摺動特性
が優れていることを特徴とする請求項１に記載の金属焼
結体複合材料。2. A porous metal sintered body that is impregnated and solidified with a light metal to form a composite material portion, and a base material side sintered body layer for reducing a difference in coefficient of thermal expansion from a light metal base material portion, And a sliding side sintered body layer that is integral with the base material side sintered body layer and forms a sliding surface, and the sliding side sintered body layer slides more than the base material side sintered body layer. The sintered metal composite material according to claim 1, which has excellent dynamic characteristics.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3738195A JPH08229663A (en) | 1995-02-24 | 1995-02-24 | Metal sintered composite material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3738195A JPH08229663A (en) | 1995-02-24 | 1995-02-24 | Metal sintered composite material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08229663A true JPH08229663A (en) | 1996-09-10 |
Family
ID=12495956
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3738195A Pending JPH08229663A (en) | 1995-02-24 | 1995-02-24 | Metal sintered composite material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08229663A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004052573A1 (en) * | 2002-12-10 | 2004-06-24 | Nhk Spring Co., Ltd. | Composite material member and method for producing the same |
| JP2006061936A (en) * | 2004-08-26 | 2006-03-09 | Toyota Industries Corp | Composite material |
-
1995
- 1995-02-24 JP JP3738195A patent/JPH08229663A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004052573A1 (en) * | 2002-12-10 | 2004-06-24 | Nhk Spring Co., Ltd. | Composite material member and method for producing the same |
| CN1325203C (en) * | 2002-12-10 | 2007-07-11 | 日本发条株式会社 | Composite material member and method for producing the same |
| US7560171B2 (en) | 2002-12-10 | 2009-07-14 | Nhk Spring Co., Ltd. | Composite material member and method for producing the same |
| JP2006061936A (en) * | 2004-08-26 | 2006-03-09 | Toyota Industries Corp | Composite material |
| JP4524591B2 (en) * | 2004-08-26 | 2010-08-18 | 株式会社豊田自動織機 | Composite material and manufacturing method thereof |
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