Effect of interfacial reaction on age-hardening ability of B4C/6061Al composites

The age-hardening ability of B4C/6061Al composites, fabricated by powder metallurgy technique, were systematically investigated through varying B4C contents (0-30 wt%), hot-pressing temperatures (560-620 °C) and holding times (30-120 min). The results showed that the quantity of Mg2Si precipitates formed in the composites after T6-treatment decreased with increasing B4C content and hot-pressing temperature, attributable to the consumption of Mg resulting from interfacial reactions. The main interfacial reaction products were MgAl2O4 and Al3BC. The formation of MgAl2O4 was determined to be the primary factor degrading the age-hardening ability of the composites. Reducing the hot-pressing temperature and holding time and increasing the Mg content were beneficial to improving the age-hardening ability of the composites. It was experimentally verified that 580 °C and 30 min were the optimal hot-pressing temperature and holding time, and the amount of additional Mg should be less than 1.5 wt%, when considering both the age-hardening ability and comprehensive properties of the composites.