MICROSTRUCTURES AND MECHANICAL-PROPERTIES OF NB3AL PRODUCED FROM NB-AL ALLOY POWDER

Intermetallic compound Nb3Al with three different compositions was pre pared by powder metallurgy using Nb-Al alloy powders, and the relation ship between microstructure and compressive properties was studied. Fl ow behavior of Nb3Al at high temperatures was associated with movement of dissociated dislocations and dynamic recrystallization. The yield stress was influenced by the presence of second phases in the compound . For example, dispersion of Nb solid solution as a second phase lower ed yield stress at all temperatures tested, while the sigma phase rais ed yield stress below 1490 K but lowered it above 1650 K.