Evolution of the structure of nanocrystalline Ni3Al in heat treatment

The thermal stability of the intermetallic compound Ni3Al with a nanocrysta lline structure is investigated. In intense plastic deformation by torsion under high quasi-hydrostatic pressure on Bridgman anvils, a completely diso rdered structure of grain size similar to 50 nm is obtained. Comprehensive investigation of the evolution of the nanocrystalline Ni3Al structure - by measuring the temperature dependence of the residual electrical resistance and the microhardness, by transmission electron microscopy, and by X-ray st ructural analysis indicates a three-stage evolution of the structure on hea ting.