Physical-Mechanical Properties of Surface Layers of NiTi Alloy Depending on the Number of Pulses of Electron Beam

The paper presents analysis of the research data on investigation of physical-mechanical properties of NiTi alloy after microsecond low-energy high-current pulsed electron beam treatment depending on the number of pulses of electron beam. Investigation of physical-mechanical properties (Young's modulus E-IT, dynamic hardness H-IT, plasticity characteristic delta(H), and shape recovery ratio eta) of NiTi surface before and after electron beam treatment was held by method of instrumented nanoindentation test. As a result electron beam modification of the surface of NiTi alloy leads to a change in the strength and plasticity characteristics in depth from the irradiation surface. The hardening of the surface layer reaches a depth of up to similar to 500 nm at n = 5 (H-IT approximate to 60 GPa), and up to similar to 1000 nm at n = 15 (H-IT approximate to 100 GPa). At a depth of more than similar to 1500 nm, the value of parameter of shape recovery ratio eta decreased by similar to 5-10%, which is due to the hardening of the modified surface layers of NiTi alloy.