Effect of Chemical Composition and Structure on the Shape Recovery Temperatures of Titanium Nickelide-Based Alloys

It is shown that the structure of alloys based on titanium nickelide, obtained by industrial technology, invariably contains titanium-rich phases of type Ti 2 Ni/Ti 4 Ni 2 (O, N), even if the nickel concentration in the B2-phase exceeds the equiatomic composition. The volume fraction of these phases depends on the smelting method, the purity of the charge, and the technology used for subsequent ingot processing. Regression equations linking shape recovery temperatures with the concentration of nickel in the B2-phase in the quenched state are presented. On the basis of these equations, a method for calculating the volume fraction of Ti 3 Ni 4 type particles released during aging is proposed.