Friction and wear properties of TC4 titanium alloy with high-speed nitriding treatment

In order to improve the surface hardness and wear resistance of TC4 titanium alloy, a high-speed nitriding treatment (HSNT) based on Ultrafast High-temperature Sintering (UHS) process was proposed. HSNT was ap-plied to the surface of TC4 titanium alloy, and the microstructure of the sample was studied by X-ray diffractometer and scanning electron microscope. The mechanical properties of the sample were tested by Vickers microhardness tester and friction and wear test device. The modified layer can be formed on the surface of TC4 titanium alloy in 2 min. The modified layer consists of two parts. The outermost layer is the nitride layer, the thickness is about 10 μm, the average microhardness is 973.55 HV_0.1, and the main component is TiN. The sub-surface layer is nitriding layer, the thickness is also about 10 μm, the average microhardness is 774.53 HV_0.1, the cross-section microhardness overall shows a trend of ladder distribution. The friction and wear test shows that under 20 N load, the friction coefficient of TC4 with HSNT is 0.406, which is reduced by 24.4%, and the wear volume of TC4 with HSNT is 0.302 mm³, which is reduced by 86.7%. The friction coefficient and wear volume of TC4 with HSNT under different loads are always smaller than that of TC4 titanium alloy, and all increase with the increase of load. Under 20 N load, the wear mechanism of TC4 is mainly abrasive wear and oxidative wear, while the wear mechanism of TC4 with HSNT is mainly adhesive wear and oxidative wear. The performance of TC4 titanium alloy with HSNT has been significantly improved, making up for the shortcomings of low hard-ness and poor wear resistance of TC4.