A comparison of the cavitation erosion resistance of TiNi alloys, SUS304 stainless steel and Ni-based self-fluxing alloy

Cavitation erosion of TiNi shape memory alloys, SUS304 stainless steel (SS) and Ni-based self-fluxing alloys has been investigated in freshwater and 3.5 wt.% NaCl solution according to the ASTM G32-85 standard method. After 300 min of cavitation erosion, the cumulative weight loss of SUS304 SS is 45 times, whereas that of Ni-based self-fluxing alloy is 15 times the value of TiNi alloys. TiNi alloys and SUS304 SS exhibit a working-hardening behavior in the early cavitation stage, and thereafter maintain constant hardness during further cavitation. However, the Ni-based self-fluxing alloy exhibits no hardening phenomenon during cavitation test. The thermoelastic martensitic transformations of TiNi alloys have important effects on their erosion characteristics. The variants accommodation, pseudoelasticity of SIM and high work-hardening rate can improve the erosion resistance of TiNi alloys. Cavitation erosion of all these alloys in freshwater is similar to that in 3.5 wt.% NaCl solution under the same testing conditions.