Sliding wear of stainless steel matrix composite reinforced with TiB2 particles

AISI 304 stainless steel reinforced with 20 vol.% TiB₂ particles were prepared by hot isostatic pressing (HIP). The dry sliding wear behaviour of this ferrous composite was investigated by means of the pin-on-disc technique. The results showed that the TiB₂ particle addition was very effective to improve the wear resistance of soft and ductile austenitic stainless steel. The volumetric wear of the composite tended to decrease with increasing applied normal loads or with sliding velocity. This was due to the formation of a deformed surface layer whose microhardness values also increased with increasing applied load. Scanning electron microscopic observation revealed that the TiB₂ particles from the metal matrix composite (MMC) matrix were fractured into smaller particulates during sliding. These fragmented particles tended to orient themselves along the sliding direction, and redistributed near the subsurface region of MMC. Consequently, the hardness of the subsurface region of MMC after sliding was higher than that of the unreinforced stainless steel.