放電焼結法で作製したAl-Si複相合金の乾式摺動特性に及ぼすSi粒子の空間分布の影響

倉本英哲　隠岐貴史　柳沢　平^*　
　　　　　　　　　　

　Al-Si複相合金において、第２相粒子であるSi粒子の空間分布が乾式摺動特性に与える影響を明らかにするために、粒子の粒径分布と空間分布傾向が異なるAl-Si複相合金を放電焼結法によって作製し、乾式での摩耗試験を行った。この時、Al-Si複相合金のSi粒子の体積率は２０％で一定とし、また、粒子の平均粒径についても、ほぼ一定とした。得られた結果は以下のように要約される。
　摩耗試験はリングオンディスクタイプで行い、リングの押さえつけ荷重を一定として試験を行った。この時、試験荷重（Ｆ）は９．８Ｎおよび４９Ｎの２種類を選択した。Ｆ＝４９Ｎ場合、
摩耗は主に凝着摩耗の形態で起こり、摩耗係数（μ）は試料によっては変わらなかった。この時、摩耗量（Ｗ）は試料の硬さ（＝強度）に依存することが分かった。Ｆ＝９．８Ｎの場合、振動の影響を受け、その摩耗形態には転がり疲れの影響が加わる。摩耗に関しては、Ｓｉ粒子を含む摩耗粉、特にＳｉ粒子の剥離挙動と材料の強度が複合的にμとＷに影響するものと考えられた。

　In order to investigate the influence of Si-particles spatial distribution of Al-Si composite on dry wear properties, the Al-20vol%Si composites with various Si-particle size and spatial distribution were made by spark sintering, and dry wear tests of the composites were performed. The results obtained were summarized as follow:
It was confirmed that the specimen hardness increased with increasing of Si-particle clustering tendency of spatial distribution, and speciments not containing large size Si-particle were harder than the another one. In this report the Ring-on-Disk type wear test was performed under the conditon that press-down force, F, of the ring against the disk is constant. Two kind of F values, 9.8N or 49N, were chosen for wear tst. In case F=49N, the wear mode was adhesive wear, and regardless of kind of specimens the same friction coefficient, μ, was obtained. In this case, it was confirmed that the wear quantities, W, depended on the specimen hardness. In case F=9.8N, the tiredness caused by vibration joined wear mode. The behavior of wear dust containing Si-particle made during wear test, especially Si-particle separated from material, and strength of composite would influence μ and W complexly.