Effects of heat-treatment and strain rate on the mechanical properties of SiC/Al composite wires-experimental and constitutive modeling

In order to investigate the effects of heat-treatment and strain rate on the mechanical properties of SiC/Al composite wires, tensile tests at different strain rates (0.001, 200, 700 and 1200 s−1) were carried out on two kinds of SiC/Al composite wires with different heat-treatment (composite wire 1: exposed at 400 °C for 40 min; composite wire 2: exposed at 600 °C for 40 min), and the stress-strain curves were obtained. The experimental results show that both of the two composite wires are rate dependent, their modulus, strength, and unstable strain all increase with increasing strain rate; the rate sensitivity is due to that of both the matrix and the fiber. The heat-treatment temperature also significantly affects the mechanical properties of the composite wire, since the strength of the composite wire 2 is about 42-46% lower than that of the composite wire 1. The mechanism of this effect is discussed. A bi-modal Weibull elastic-plastic coated-fiber-bundles model is established to describe the rate-dependent stress-strain relationship of SiC/Al composite wire, which fits the experimental results well.