Effect of heat treatment on the structural and phase transformations and mechanical properties of TiNi alloy subjected to severe plastic deformation by torsion

Effect of annealing on the structural and phase transformations and mechanical properties of large-size samples of the Ti 49.4 Ni 50.6 alloy preliminary subjected to severe plastic deformation by torsion under a high pressure (HPT) is studied. The study was performed by transmission and scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction, and measurements of mechanical properties. The annealing was found to result in the nanocrystallization of initial samples amorphized by HPT. In this alloy, the high-strength uniform nanostructured state is formed the size of nanocrystalline grains of which and the mechanical properties depend on the temperature and time of annealing.