TITANIUM DIBORIDE PARTICLE-REINFORCED ALUMINUM WITH HIGH WEAR-RESISTANCE

A TiB2 particle (61 vol%, 4 mu m mean size) reinforced aluminium fabri cated by liquid-aluminium infiltration was subjected to unlubricated r olling wear and was found from the weight loss to be 1.5 times more we ar resistant than 17-4 ph stainless steel, twice as wear resistant as 1020 steel, 7.5 times more wear resistant than 2024 aluminium, and 12. 8 times more wear resistant than the aluminium matrix. This wear resis tance is attributed to the lack of particle pull-out and the ability o f the TiB2 particles to protect the softer underlying matrix from abra sion. This composite was approximately three times more wear resistant than AlN particle (50 vol%)-reinforced aluminium. The greater wear re sistance of Al/TiB2 compared to Al/AlN is due to the slow wear of the TiB2 particles and the AlN particle pull-out. A slight decline in tens ile strength and no effect on the modulus was observed in Al/TiB2 afte r heating at 300 or 600 degrees C for 240 h. This high-temperature sta bility is attributed to the lack of reactivity between TiB2 and the al uminium matrix.