Effect of rolling reduction on microstructures and tensile properties of hot-rolled Al18B4O33 whisker-reinforced 6061 aluminum alloy composite

The rolled sheets of Al18B4O33 whisker-reinforced 6061 aluminum alloy composite rolled at a relatively low temperature of 400 °C have been obtained. The microstructures and tensile properties of the rolled composites have been investigated. A large number of microcracks, generated from the serious whisker fracture under a low rolling reduction, result in poor tensile properties of the rolled composite with a 30% reduction. The increasing reduction causes the whiskers to rotate to the rolling direction and prompts the aluminum matrix grains to fill the microcracks. The healing of microcracks and the oriented alignment of whiskers greatly improve the tensile properties of the rolled composites. The results show that a sufficient reduction facilitates high mechanical properties of the hot-rolled composite.