Superplasticity in a 17 vol% SIC particulate-reinforced ZK60A magnesium composite (ZK60/SiC/17p)

The superplastic characteristics of a 17 vol.% SiC particulate-reinforced ZK60A magnesium composite (ZK60/SiC/17p) have been studied. The composite has a fine microstructure (grain size similar to 0.5 mu m) and is stable at high temperatures. As a result of the fine microstructure, the composite exhibits superplasticity (with an elongation to failure of 350%) at very high strain rate (similar to 1 s(-1)). The superplastic properties of the composite, including elongation, strain rate sensitivity, activation energy, grain size dependence, and cavitation, were all characterized. From experimental results, i.e., the strain rate sensitivity value, the grain size dependence of strain rate, and the activation energy, the operative superplastic deformation mechanism in ZK60/SiC/17p is proposed. A comparison between the superplastic behavior of the composite and that of magnesium alloys, and particularly the unreinforced magnesium alloy counterpart of the composite, has also been made.