Microstructure and Wear Resistance of Ti17 Titanium Alloy after Surface Treatment with Composite Strengthening Process

The surface of Ti17 titanium alloy was composite strengthened by the electrical discharge surface hardening with silicone bronze and YG-8 alloy as electrode material respectively and consequent ion beam enhanced deposition with silicone bronze, and the effects of different electrode materials on the microstructure and wear resistance were investigated. The results show that the composite strengthening coating on the Ti17 titanium alloy was composed of the electrical discharge strengthening layer and bronze deposition layer. The bronze deposition layer had a compact microstructure without defects such as pores and micro-cracks and bonded well with the electrical discharge strengthening layer. The thickness of the composite strengthening coating formed with the electrode made of silicone bronze was 6 μm, and the surface hardness of the surface strengthened titanium alloy was 517 HV, and then the wear resistance was 20 times larger than that of Ti17 titanium alloy without strengthening; the thickness of the composite strengthening coating with YG-8 alloy as electrode material was 15 μm, the surface hardness was 537 HV，and the wear resistance was 30 times larger than that of the alloy without strengthening. The friction coefficient of the Ti17 titanium alloy after composite strengthening was slightly reduced compared with that before strengthening.