Cavitation erosion behaviors and damage mechanism of Ti-Ni alloy impacted by water jet with different standoff distances

The cavitation erosion of Ti-Ni alloy is explored on a cavitating liquid jet with different standoff distances. The cavitation erosion characteristics of Ti-Ni alloy specimens are analyzed, and the influences that different standoff distances of the water jet have on cavitation erosion are explored. The results of cavitation erosion outcomes under different standoff distances of 6 mm, 8 mm, 10 mm, 12 mm, 14 mm and 16 mm show slight deformation, grain boundary cracking and formation of initial micro-pits, pits of maximum depth around 50 mu m, more pits of maximum depth around 80 mu m with micro-cracks, obvious plastic deformation traces with some pits, bulges and slip bands, respectively. When the Ti-Ni alloy is impacted by water jet with a standoff distance of 12 mm for 4 hrs, the surface microstructure undergoes substructural evolution and new fine grains form, with obvious stress concentration and dislocation accumulation appearing on the subsurface.