Investigation of thermomechanical characteristics of shape-memory alloys of the Ti-Ni-Nb system and of the effect of heat treatment on them

The properties of shape-memory titanium nickelide-based alloys alloyed with niobium have been investigated for use in developing progressive technology for thermomechanical joints of pipelines and cylindrical elements of constructions of couplings fabricated from these alloys. In the process of the investigations, the elemental and phase compositions of alloys of the Ti-Ni-Nb system in the cast and pressed states have been determined; their microstructure, kinetics, and temperatures of phase transformations have been studied; the main mechanical characteristics have been determined; the thermomechanical characteristics and the effect of different types and regimes of heat treatment on them have been investigated. The results of these investigations confirmed the suitability of the alloys for use in thermomechanical joints of pipelines; couplings can be stored at temperatures of up to 40°C without a loss of deformation induced in them. By changing certain mechanical and thermomechanical characteristics of alloys of the Ti-Ni-Nb system in the cast and pressed states using different types and regimes of heat treatment, the field of employment of these materials can be expanded.