LAUSR

Abstract In this study, high-temperature tensile properties and microstructure of ZK60/SiCw composite were investigated in “as-cast” and “extruded + precipitation-hardened” conditions. Stir casting followed by extrusion and aging at 175 °C for 12 h was employed to prepare the composite samples containing 5 vol% SiC whiskers. Aligned whiskers and the severely deformed matrix resulted in a quasi-continuous network structure of the reinforcement and laminar structure of the matrix. Tensile tests, conducted in the temperature range of 25–350 °C, revealed that the anisotropic structure led to an improvement in the ductility and strength. The elastic modulus of the composite was dependent on the alignment and distribution of the reinforcement. While the elastic modulus in the extrusion direction was close to the upper bound of the Halpin–Tsai (H-T) model at temperatures below 250 °C, it approached to the lower bound of the model at temperatures above 300 °C. Moreover, 0.2% proof stress, ultimate tensile strength and elastic modulus decreased nonlinearly with temperature. Examination of the fracture surfaces revealed the fracture of whiskers with slight pull-out due to the strong whisker/matrix interface.