Investigation of the Effect of Pulsed Helium Ion and Helium Plasma Flows on the Structure and Mechanical Properties of Surface Layers of Ti–Nb–Mo–Zr–Al Alloys

Abstract—The effect of irradiation with pulsed helium ion beams and helium plasma on the structural characteristics and mechanical properties of titanium alloys with the following compositions (wt %): Ti–0.5 Nb–0.5 Mo–3 Zr–3 Al; Ti–1 Nb–1 Mo–3 Zr–3 Al; and Ti–1.5 Nb–1.5 Mo–3 Zr–3 Al was investigated. The irradiation was carried out using a Plasma Focus type device with power flux densities of q = 2 × 108 W/cm2 for helium ions and q = 4 × 107 W/cm2 for helium plasma, with pulse durations of 20–100 ns. Metallographic and X-ray phase analyses were performed and the mechanical properties (ultimate strength, yield strength, and elongation) and microhardness of the alloy samples before and after irradiation were determined. The irradiation caused a slight (less than 10%) decrease in the strength and plasticity indicators of the alloy samples, while the microhardness remained practically unchanged.