Effect of manganese on the cavitation erosion resistance of iron–chromium–carbon–silicon alloys for replacing cobalt-base Stellite

The cavitation erosion behavior of Fe–Cr–C–Si–xMn (x = 5, 10 and 15 wt%) alloys were investigated for 50 h using 20 kHz vibratory cavitation erosion test equipment. Low-Mn alloys (<5 wt% Mn) and high alloys (>10 wt% Mn) exhibited the γ → α′ and γ → ε strain-induced martensitic transformation, respectively. Mn-addition above 10 wt% was observed to increase the cavitation erosion resistance of the Fe-based alloy. It was concluded that the γ → ε strain-induced martensitic transformation would be more beneficial than the γ → α′ strain-induced martensitic transformation due to the blocking of the dislocation motion, thus increasing the hardness of the matrix by effective work-hardening. The phase transformation was examined by X-ray diffraction before and after the cavitation erosion tests and the surface damage of the tested specimens was also investigated by scanning electron and optical microscopy.