Effect of thermal cyclic nitriding modes on microstructure and chemical composition of titanium alloy surface layers

Abstract

A method has been developed for cyclic low-temperature ion nitriding using a plasma source with an integrally cold hollow cathode, which is superior in performance to a source with an incandescent cathode. The results of the effectiveness of the developed method are presented. It has been established that the greatest influence on the microhardness of titanium alloys is exerted by the bias voltage and the l ocation of the surface with respect to the plasma flow. Microstructural studies have shown that the α-phase is stabilized in the near-surface layer due to nitrogen diffusion, grain growth is not observed. Alloy VT8M1 retains a two-phase structure. The possibility of controlling nitriding by changing the duration and direction of surface saturation is also shown.