Effect of heat treatment on the mechanical properties of aluminum-borate whisker reinforced 6061 aluminum alloy.

Effect of heat treatment (solution treatment and aging treatment at 443K) on the tensile strength between room temperature and 773K was investigated of the aluminum-borate whisker reinforced (Vf=0.16 and 0.29) 6061 aluminum alloys. Tensile strength of the as-cast 0.29 Vf composite is in the measured temperature range about twice higher than that of the matrix alloy. No whiskers are observed on the fracture surfaces of the composites up to 573K. Both tensile strengths of the matrix alloy and of the 0.29 Vf composite are increased by aging treatment. The degree of the increase is, however, smaller for the composite than the matrix alloy. In the heat-treated composites, whiskers are observed on the fracture surfaces. This result shows that the strength of matrix alloy/whisker interface is decreased by the heat treatment.