Superplasticity of large-grained Ni-Al alloy

High temperature deformation behaviors of single phase Ni-40% Al (atom fraction) ally with initial grain size of 220 μm were examined. It was found that the alloy exhibits superplastic behavior under the initial strain rates of 5×10-5-10-5×4 s-1 in 1000-1100°C. A maximum elongation of 340% was obtained at 1050°C with the strain rate sensitivity of 0.3. The activation energy was determined to be about 289 kJ/mol. The initial large grain microstructure becomes much fine after the superplastic deformation. The large grained superplastic phenomenon can be explained by the continuous recovery and recrystallization.