Structural and phase transformations and properties of TiNi–TiCu quasi-binary alloys

The influence of copper doping (25 at. %) upon the structural and phase transformations of triple alloys of the TiNi–TiCu quasi-binary cut is studied by transmission and scanning electron microscopy and electron and X-ray diffraction. A generalized complete diagram of $B$2 $\leftrightarrow$ $B$19', $B$2 $\leftrightarrow$ $B$19 $\leftrightarrow$ $B$19', and $B$2 $\leftrightarrow$ $B$19 thermoelastic transformations proceeding upon cooling as the copper content increases in the intervals of 0–8, 8–15, and 15–25 at. %, respectively, is constructed. Specificities of changes in the mechanical properties and microstructure of $B$19 and $B$19' martensites in relation to copper doping are studied.