Understanding grain growth behavior in a superplastic nickel-based nanocomposite: Influence of mechanical deformation and heat treatment

In this paper, the grain growth behavior of a SiC particle-reinforced nickel-based nanocomposite was studied at temperatures of 410°C and 450°C and at strain rates ranging from 8.3 × 10-4 s-1 to 5 × 10-2 s-1. A significant grain growth was observed in both the annealed and deformed specimens. It was found that the static grain growth contributed more to the overall grain growth, and the dynamic grain growth was relatively small at high strain rates. The findings suggested that the thermal stability of the composite should be enhanced as its superplasticity and post-formed properties were greatly affected by the grain growth. Based on the observed microstructural changes, the deformation mechanisms of the composite are also discussed in this paper.