Physical-mechanical properties of synthesized layers of Ti–Ni–Nb-based surface alloys, formed on the surface of TiNi alloy

The physical-mechanical properties (microhardness, Young’s modulus, plasticity characteristic, shape recovery ratio) of the synthesized layers of Ti–Ni–Nb-based surface alloys of $\sim$2 $\mu$m thickness, formed on the surface of TiNi alloy by the additive thin-film electron beam method were investigated by the instrumented indentation. It was found that the change in physical-mechanical properties in the synthesized surface alloys based on Ti–Ni–Nb is due to their layered structure. In particular, it is due to the thickness of the sublayers, their phase composition, and the structural states of the phases (nanocrystalline and amorphous). It was established that high strength and elastic-plastic parameters of the outer layer and a monotonic change in the physical-mechanical properties from the surface to TiNi substrate are provided in the surface Ti–Ni–Nb alloy with a lower volume fraction of the amorphous phase in the synthesized layers. It was found that the multilayer structure of the surface Ti–Ni–Nb alloy and the monotonically change in the physical-mechanical properties to the substrate ensure high mechanical compatibility of the synthesized layers of surface alloys with the TiNi substrate.