Abstract

The powder mixtures of Al, Ti and Cr were mechanically alloyed to obtain nanocrystalline powders of Ti_25Cr_8Al_67 composition. Both FCC phase and undissolved metal chromium formed by MA. During the annealing of the MA powders, the phase transition from FCC to ordered Ll_2 started at ~300°C and was completed below 600°C. As a result of the high-temperature compressive test for the MA powder compacts, the stress-strain curves showed serrated yielding behavior at 400 and 600°C, and softening phenomenon below the strain rate of 5times10-3s-1 at 800°C. The compressive yield strength as a function of test temperatures showed the nature of the positive-temperature dependence which has the peak temperature around 600°C.