Effect of Al content on impact resistance behavior of Al-Ti-B₄C composite fabricated under air atmosphere

Reaction behavior, mechanical property and impact resistance of TiC-TiB₂/Al composite reacted from Al-Ti-B₄C system with various Al content via combination method of combustion synthesis and hot pressed sintering under air was investigated. Al content was the key point to the variation of mechanical property and impact resistance. Increasing Al content could increase the density, strength and toughness of the composite. Due to exorbitant ceramic content, 10wt.% and 20wt.% Al-Ti-B₄C composites exhibited poor molding ability and machinability. Flexural strength, fracture toughness, compressive strength and impact toughness of 30-50wt.% Al-Ti-B₄C composite were higher than those of Al matrix. The intergranular fracture dispersed and defused impact load and restricted crack extension, enhancing the impact resistance of the composite. The composite with 50wt.% Al content owned highest mechanical properties and impact resistance. The results were useful for the application of TiC-TiB₂/Al composite in impact resistance field of ceramic reinforced Al matrix composite.