Tensile properties of ZnO- and ZnAl 2 O 4 -coated aluminum borate whiskers reinforced aluminum composites at elevated temperatures

Abstract

ZnO- and ZnAl₂O₄-coated aluminum borate whiskers reinforced pure aluminum composites were fabricated by squeeze casting. The tensile properties of the composites at elevated temperatures were tested. The results indicate that the maximum tensile stress of the composite decreases with the increase of tensile temperature; however, the tensile strain of the composite initially increases and later declines. ZnO, especially, ZnAl₂O₄ coating of the whiskers can effectively improve the ultimate tensile strength of the composite at elevated temperatures. On the basis of fractographic analysis, the fracture mechanisms of the composites at elevated temperatures were also investigated.