Effect of Vacuum Ion-Plasma Nitriding on the Structure and Properties of a Ti-5553 Titanium Alloy

The effect of vacuum ion-plasma treatment conditions on the surface layer structure of a preliminary strengthened pseudo-β Ti-5553 titanium alloy is studied. During nitriding, the structure comprising titanium nitrides and an interstitial nitrogen solid solution in α titanium is found to form in the modified layer. Vacuum ion-plasma nitriding is shown to increase the microhardness of the surface of Ti-5553 alloy samples from 430 to 650 HV_0.05, i.e., almost 1.5 times as compared to that of the state after strengthening heat treatment. The application of the TiN titanium nitride is noted to increase the microhardness by 2 times, namely, to 910 HV_0.05, whereas a combination of two methods (nitriding and titanium nitride deposition) increases the microhardness to 890 HV_0.05.