High-pressure strengths of Ni3Al and Ni-Al-Cr

High-pressure x-ray diffraction on Ni3Al, non-hydrostatically compressed at room temperature to 30 GPa in radial geometry can be interpreted in terms of a hydrostatic pressure-volume equation of state. We found the yield strength of Ni3Al to increase from about 0.2 to 2 GPa as pressure increases from 0 to 30 GPa. Yield-strength values determined from x-ray diffraction in axial geometry by including a Poisson ratio effect and pressure gradient methods are in good accord with each other. Our results indicate that the strengths of both pure and Cr-doped (7 at. %) Ni3Al increase with pressure, with the yield strength of Ni3Al slightly higher than Ni-Al-Cr alloy.