Abstract
Influences of dispersion and sizes of proeutectic Si on wear resistance of P/M Al-Si alloys using the prealloying method and premixing method have been investigated. As a result, discretely dispersed proeutectic Si showed excellent wear resistance in comparsion with uniformly dispersed one. The cause is considered to be the unclosed Si soft phase which has been prefarentially wom away, consequently acting on forming oil grooves and burying worn particles. Further more the existence of the optimum size of proeutectic Si on wear resistance was comfirmed.In the case of finer particles, only Al-Si alloy (pin) was worned away substantially. On the other hand, in the case of larger particles, both the Al-Si alloy (pin) and the mating material (steel disc) were excessively worned away. It is assumed therefore that the finer proeutectic Si particles are not effective as hard particles, on the contrary, larger proeutectic Si particles increase the abrasive wear against the mating material, and those buried into the mating material initiate wear of Al-Si alloy at the same time.
