Effect of strain-induced ε and α′-martensitic transformation on cavitation erosion resistance in austenitic Fe‐Cr‐C‐MnFe-Cr-C-Mnti alloys

Effect of strain-induced ε and α′-martensitic transformation (SIMT) on cavitation erosion resistance was investigated in austenitic Fe-Cr-C-Mn alloys as a function of Mn concentration. Stacking fault energy (SFE) of Fe-16Cr-0.4C-xMn (x=5, 10, and 15) alloys decreased with increasing Mn concentration. As the SFE decreased with increasing Mn concentration, the volume fraction of transformed α′-martensite decreased whereas the fraction of ε-martensite increased such that the SIMT type changed from γ→α′ to γ→ε+α′. It was shown that the cavitation erosion resistance of the γ→ε+α′ type alloy was superior compared to the γ→α′ type alloy. The improvement in cavitation erosion resistance was ascribed to the presence of the ε-martensite, hindering the propagation of the grain boundary damage into the grains.