Damage mechanism of cavitation erosion in austenite→martensite phase transformable Fe–Cr–C–Mn/Ni alloys

The damage mechanism of cavitation erosion was investigated for austenite (γ)→martensite (α') phase transformable Fe–Cr–C–Mn/Ni alloys. In the case of phase transformable alloy, α' was formed evenly within the grains. It was assumed that the α' phase transformation absorbed the collapse energies of cavities and obstructed the propagation of cracks from grain boundaries into the grain. Consequently, the resistance to cavitation erosion of the grain was enhanced due to the α' phase transformation and the damage occurred mainly at grain boundaries. When the α' phase transformation did not occur, the onset of cavitation erosion damage was initiated at the shear bands within the grain and at the grain boundaries, simultaneously. •Cavitation erosion damage was initiated at grain boundaries and shear bands.•The damage at the shear bands within the grain accelerated mass loss rate.•In phase transformable alloy, martensite was formed evenly within the grains.•α' Transformation prevented crack generation and propagation.