INFLUENCE OF OXIDATION TREATMENT ON WEAR RESISTANCE OF NEAR β Ti-5321 TITANIUM ALLOY

The influence of oxidation temperature on tribological properties of near [Formula: see text] Ti alloy Ti-5Al-3Mo-3V-2Cr-2Zr-1Nb-1Fe (Ti-5321, wt.%) has been studied in this work. The results show that the wear resistance of alloy can be significantly enhanced by oxidation treatment, closely depending on heating temperature. Upon heating, the interstitial O continuously diffuses from the outer to inner regions forming the oxidation and diffusion layers, and the other elements migrate from inner to outer layer caused by concentration gradient. During friction tests against stainless steel, the oxidation and abrasive wears become the dominating mechanisms gradually with the heating temperature climbing, and the effect of adhesive wear mechanism weakens. In view of comparatively low temperature, the oxidation layer may be incomplete, such as 873[Formula: see text]K, and when the treatment is performed above 973[Formula: see text]K, a dense and complete oxidation layer protecting the alloy can be obtained. Server friction and weakened wear resistance should occur when the alloy is oxidized at high temperatures due to the reduced adhesion to substrate, i.e. 1073[Formula: see text]K. The best tribological properties of alloy under oxidation treatment are obtained at 973[Formula: see text]K, and the microhardness, wear ratio and average friction coefficient are 612 ± 16[Formula: see text]HV, 1.2× 10[Formula: see text] [Formula: see text]mm 3 /(N⋅m) and 0.285± 0.007, respectively.