Abstract
Formation behavior of wear-induced layer in Fe-Ni alloys is investigated. The wear-induced layer i s observed just below worn surface and it has very fine microstructure. Moreover, reverse transformation occurs around worn surface, and volume fraction of austenite (γ) phase increases. As a result, microstructure and hardness of the wear-induced layer become the same regardless of initial microstructure. From these results, it is found that both microstructural refinement and reverse transformation occur during wear. These phenomena are induced by large shear strain and frictional heat due to wear. Based on these obtained results, formation behavior of the wear-induced layer in stainless steel (SUS304) is also investigated. As well as Fe-Ni alloys, the wear-induced layer with fine microstructure is formed just below worn surface of SUS304. However, strain-induced martensitic transformation occurs without reverse transformation. This is because that amount shear strain induced by wear is not enough to cause reverse transformation. Finally, it is concluded that phase transformation induced by wear is controlled by both the amount of shear strain and the frictional heat.
