Cavitation erosion resistance of the titanium alloy Ti–6Al–4V manufactured through additive manufacturing with various peening methods

Abstract

Additive manufacturing (AM) can produce parts with complex shapes quickly; therefore, it is applied in the manufacturing of impellers for pumps and screws for ships. However, cavitation erosion may occur in these fluid machine components. The fatigue strength and fatigue life of parts manufactured through AM are weaker than those of bulk metals, and the surfaces of these parts are rough owing to AM. Thus, the cavitation erosion resistance of the AM metal may be weaker than those of bulk metals. In this study, to investigate the cavitation erosion resistance of the AM metal, a cavitation erosion test was conducted by using a cavitating jet. The test specimens of titanium alloy Ti–6Al–4V manufactured through electron beam melting were treated using various peening methods that succeeded in improving the fatigue strength of the AM metal. The cavitation erosion resistance of the as-built AM metal without surface treatment was much lower than that of the bulk metal. When the results of the AM metal treated using various peening methods were compared with those of the as-built metal, the erosion rate was observed to have decreased by approximately 40% and 95% for cavitation peening and abrasive cavitation peening, respectively. Therefore, it was found that the cavitation erosion resistance of the AM metal can be improved through peening treatment.