Gas Nitriding and Oxidation of Ti-6Al-4V Alloy

Abstract

The Ti-6Al-4V alloy was nitrided at 950 °C for 8 h by heating under atmospheric nitrogen in order to improve its surface hardness and oxidation resistance. Nitrogen diffused into the Ti6Al4V alloy, and formed ~40 μm-thick coating consisting of TiN as the major phase and Ti2N as the minor one. Nitriding increased the surface microhardness through the strengthening effect of interstitial nitrogen and the formation of nitrides. Oxidation at 700 °C for 10 h formed a superficial TiO2 layer on the coating.