Interfacial microstructure and tensile properties of 6061Al matrix composite reinforced with ZnAl₂O₄-coated Al₁₈B₄O₃₃ whiskers

The ZnAl₂O₄ coating was fabricated on the surface of the aluminum borate whiskers by a sol-gel method,and the 6061Al matrix composite reinforced with ZnAl₂O₄-coated aluminum borate whiskers was fabricated by squeeze casting. The effects of the ZnAl₂O₄ coating on interface wet tability,tensile properties at room temperature and interfacial thermal stability after thermal exposure of the composite were investigated. The experimental results show that the nano- ZnAl₂O₄ coating can remarkably improve the interface wet tability of the composite,and thus improve the tensile properties at room temperature of the composite. The uniform ZnAl₂O₄ coating can effectively hinder the interfacial reaction and make the composite keep good thermal stability. At the same time,the effect of the coating on the tensile fracture behavior of the composite in as-cast and after thermal exposure was investigated. The fracture of whiskers is in the majority during the tensile deformation of the aluminum matrix composite reinforced with uncoated aluminum borate whiskers,however,the pull-out of whiskers is in the majority during the tensile deformation of the aluminum matrix composite reinforced with ZnAl₂O₄-coated aluminum borate whiskers.