Microstructure of Nb–Al powders consolidated by spark plasma sintering process

Mechanically alloyed and blended Nb–Al, Nb–Al–W, Nb–Al–Mo and Nb–Al–N powders were sintered by a spark plasma sintering process and the microstructure and mechanical properties of compacts were investigated. Fully-densed Nb–Al compacts are obtained when sintering temperature is higher than 1773 K, although the microstructure of compacts consolidated from blended elemental powders is much coarser than that of compacts consolidated from mechanically alloyed powders. The microstructure of Nb–Al–W and Nb–Al–Mo compacts was not homogeneous, probably because of insufficient sintering time. Nb–Al compacts, in which the Nb2N phase is dispersed, was found to be prepared by sintering blended Nb and AlN powders by the spark plasma sintering process.