Titanium diboride particle-reinforced aluminium with high wear resistance

ATiB₂ particle (61 vol%, 4 μm mean size) reinforced aluminium fabricated by liquid-aluminium infiltration was subjected to unlubricated rolling wear and was found from the weight loss to be 1.5 times more wear 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 resistance is attributed to the lack of particle pull-out and the ability of the TiBa particles to protect the softer underlying matrix from abrasion. This composite was approximately three times more wear resistant than AlN particle (50 vol%)-reinforced aluminium. The greater wear resistance 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 tensile strength and no effect on the modulus was observed in Al/TiB₂ after heating at 300 or 600°C for 240 h. This high-temperature stability is attributed to the lack of reactivity between TiB₂ and the aluminium matrix.