Mechanical and Microstructural Response of Ni₃AI at High Strain Rates and Elevated Temperatures

In this paper, the effect of strain rate and temperature on the substructure evolution and mechanical response of Ni3Al will be presented. The strain rate response of NijAl was studied at strain rates from 10-3 s-1 (quasi-static) to 104 s-1 using a Split Hopkinson Pressure Bar. The Hopkinson Bar tests were conducted at temperatures ranging from 77K to 1273K. At high strain rates the flow strength increased significantly with increasing temperature, similar to the behavior observed at quasi-static rates. The work hardening rates increased with strain rate and varied with temperature. The work hardening rates, appeared to be significantly higher than those found for Ni270. The substructure evolution was characterized utilizing TEM. The defect generation and rate sensitivity of Ni3AL are also discussed as a function of strain rate and temperature.