Cavitation Erosion Behavior Of Titanium And Ti-6Al-4V Alloy

Cavitation erosion is a phenomenon that occurs in components contacting liquids in fluid machinery and in many other industrial and biomedical components. Cavitation erosion severely damages components and greatly reduces service life of the machine and the component. However, cavitation erosion is a complex process and the mechanism of cavitation erosion is not established perfectly by now. Therefore, it is crucial to investigate the mechanism of cavitation erosion and apply various methods in order to reduce the damage.In this paper, the process and mechanism of cavitation erosion behavior indeionized water and 3.5%NaCl solution of Ti and Ti-6Al-4V alloys were discussed. The variation of cumulative mass loss, microstructure, surface appearance, hardnessduring the cavitation erosion behavior were examined. The characteristics of initiation and development of cavitation erosion are investigated. The results revealed that materials are easier to be damaged by cavitation in 3.5%NaCl solution and Ti-6Al-4Valloys showed better cavitation erosion- resistance.A solution- aging treatment method was developed to improve the cavitation erosion- resistance of Ti-6Al-4V alloys. Duplex and basketweave microstructure wasobtained by two solution-aging treatment methods. The results revealed that Ti-6Al-4V with duplex and basketweave microstructure both show better cavitation erosion- resistance than annealed Ti-6Al-4V. Ti-6Al-4V with basketweave microstructure exhibited lowest cumulative mass loss in the test and the best cavitation erosion- resistance due to the property of superior anti- fatigue property.A surface modification method of Mo ion implantation was also used to enhance the cavitation erosion- resistance of Ti-6Al-4V alloys. The modified material showed a certain degree of improvement of cavitation erosion- resistance. However, the layer of Mo ion implantation didn't effectively hinder the formation and extension of cracks and pits, which led to a relatively large cumulative mass loss for 8h cavitation erosion in 3.5% NaCl solution.