Investigation on superplasticity of a NiAl-Fe in-termetallic alloy

The superplasticity and its mechanisms of a NiAl-Fe duplex alloy have been investigated. Its microstructure consists of β-NiAl phase and γ-Ni solid solution. This alloy exhibits superplasticity with the elongation as high as 233% at 1123-1223 K and strain rates of 1.04×10-4 - 1.04×10-2 s-1. After superplastic deformation, it is found that the fracture tips do not contain any cavity, and the fracture surfaces appear to be ductile type. SEM observations suggest that dynamic recrystallization (DRX) occurs in β-phase, while grain breaking occurs in γ-phase.