Solid Particle Erosion Behavior And Failure Mechanism Of Tizrn Coatings For Ti-6al-4v Alloy

Arc-plasma deposition technique was used to prepare coatings on a Ti-6Al-4V alloy surface due to its high coating deposition rate and superior coating-substrate bonding strength. The effects of the coatings on the erosion resistance of the alloy to solid-particle erosion at low- (30 degrees) and high- (90 degrees) impact angles were investigated. The results indicated that all coatings significantly improve the erosion resistance of the titanium alloy at an impact angle of 30 degrees. It was attributed to the high microhardness and excellent bonding strength of the coatings. However, at a high-impact angle (90 degrees), the thin monolayer coating was worn off after the erosion test and the failure mechanism of this coating was shear fracture and interface cracking of columnar crystals. With increasing of the coating thickness, the failure mechanism changed to single shear fracture and the thick monolayer coating retained the protection capability for the titanium alloy surface after this erosion. Moreover, compared with the monolayer coating, the multilayer coating as thick as the thick monolayer coating had a superior erosion resistance and slighter shear fracture under this erosion test condition. It was mainly due to the good toughness and strength, sufficiently high dynamic loading capability of the multilayer coatings.