Features of the microstructure of the shape-memory Ti–51 at %Ni alloy subjected to aging at different temperatures are studied. Along with metallographic analysis performed by optical and electron microscopy and X-ray diffraction analysis, room-temperature tensile tests of the mechanical properties are performed. The alloy in the aged state is found to be characterized by the high level of mechanical properties (the ultimate strength is up to 1200 MPa and the relative elongation, 35%) owing to the highly dispersed homogeneous decomposition and the simultaneous strengthening and increase in the plasticity as a result of strain-induced martensitic transformation.