Effects of whisker surface treatment on microstructures, tensile properties and aging behaviors of Al18B4O33w/6061Al composites

CuO was coated on the surface of Al18B4O33 whiskers by hydrothermal synthesis and CuO coated Al18B4O33 whiskers reinforced 6061Al composites with different coating contents were fabricated by squeeze casting. The preparation process and characterizations of the CuO coated Al18B4O33 whiskers were studied. The effects of CuO coating of whiskers on the microstructures, tensile properties and aging behaviors of the composite were investigated. The results showed that a uniform CuO coating of Al18B4O33 whiskers could be prepared by hydrothermal synthesis. CuO reacted with molten 6061Al during squeeze casting and meanwhile a layer of continuous MgAl2O4 formed at the interface. With increasing the contents of CuO coating on whiskers, the ultimate tensile strength of the composite gradually increased. The elongation to fracture of the composite initially increased and later decreased. Impressively, the ultimate tensile strength of the composite could be further improved after T6 heat-treatment. CuO coating of the whiskers could also obviously change the aging behaviors of the composite.