Low-temperature ion nitriding of titanium alloys

Abstract

This paper presents the results of two series of experiments on the process of low-temperature ionnitriding of titanium alloy VT6 in a non-self-sustained high-current arc discharge and in a glowdischarge in the temperature range T = 450–600 °C for t = 1 h. It is shown that the temperatureincrease from 450 °C up to 600 °С leads to an increase in the depth of the nitrided layer by afactor of 3. The results of X-ray phase study, roughness, residual stresses in the surface layer of thesamples are presented. It is shown that the temperature of ion nitriding affects the surface roughnessof the samples. With an increase in temperature from 450 to 600 °C, the value of the roughnessof the treated surface increases by 2–2.5 times. It has been established that after low-temperatureion nitriding in a non-self-sustained high-current arc discharge, tensile residual stresses are formedon the surface, and after treatment in a glow discharge, compressive stresses are formed. In this case,the nitriding temperature affects the sign and magnitude of surface residual stresses.