SUPERPLASTICITY OF LARGE-GRAINED Ni-45Al

High temperature deformation behaviors of single phase Ni-45Al alloy with initial grain size of 270 μm were examined. It was found that the alloy exhibits superplastic behavior under an initial strain rate of 1×10-4 s-1 to 2.5×10-2 s-1 at 1000 ℃ to 1100℃. A maximum elongation of 245% was obtained at 1075 ℃ with the strain rate sensitivity of 0.3. The activation energy was determined to be about 320 kJ/mol. The initial large grain microstructure became much finer after superplastic deformation. The large grained superplastic phenomenon could be explained by continuous recovery and recrystallization.