Abstract
We discussed densification behavior of vacuum hot pressing of Nbe25mol%Al composition powder and structural and mechanical property of the compact. Nb-25mol%Al powder was prepared by mechanical alloying for 1800ks and had an average grain size of 7nm. Vacuum hot pressing condition used here was 1173-1273K, 50-200MPa and 10.8ks. Maximum relative density of the compact was 99.8% of theoretical density under the hot pressing condition of 1273K-200MPa-10.8ks. Hot pressed compact consisted of mainly Nb3Al phase and a certain amount of Nb2Al and Nb2C phase. Hot pressed compact exhibited high Vickers hardness value of HV 1520 due to very fine grain size about 30nm and presence of dispersed carbide particle. Creep deformation was occurred over the temperature of 1273K and the compact exhibited value of 5.65 for the stress exponent at 1373K by using high temperature hardness measurement technique.
