Microstructural factors affecting superplastic properties in magnesium-based composites

Abstract

Effect of microstructural factors on superplastic behavior in magnesium-based composites was reviewed in order to obtain insights on ways to enhance the superplastic properties, such as highstrain-rate superplasticity, low-temperature superplasticity, and high ductility. The review shows that the reduction in grain size of the matrix directly increases the strain rate and/or decreases the temperature for optimum superplastic flow. The effect of reinforcement addition is shown to reduce the superplastic elongation, but enhance the superplastic strain rate, presumably owing to grain size stability of composites at high temperatures. Ductility enhancement is not necessarily attained by refining initial grain size. It is suggested that it is necessary to disperse the reinforcement uniformly in order to obtain higher ductility.