Microstructures and room temperature mechanical properties of NiAl prepared by high pressure reaction sintering

The microstructures and room temperature compressive mechanical properties of a near-stoichiometric NiAl manufactured by a new high pressure reaction sintering (HPRS) process are investigated. Applying a very high uniaxial pressure (2 GPa) leads to considerable lowering of the sintering temperature and reducing the hold time gives NiAl with a good sintering density. The HPRS NiAl consists of beta-NIAl with a B2 structure containing a high density of dislocations, 3.5 x 10(9) cm(-2), and very fine Al2O3 particles. The NiAl exhibits quite high true compressive strain, 14.5%, and a reasonably high yield strength, 526 MPa. The effects of employing the high pressure in the HPRS process on the reaction sintering, microstructures and mechanical properties of the NiAl are studied.