Cavitation erosion resistance of Fe-26Mn-6Si-7Cr-1Cu shape memory alloy

Abstract

The cavitation erosion of low stacking fault energy Fe-26Mn-6Si-7Cr-1Cu shape memory alloy has been investigated in water using an ultrasonic vibratory apparatus, and compared with the behaviour of 0Cr13Ni5Mo stainless steel. It is shown that Fe-26Mn-6Si-7Cr-1Cu alloy has higher cavitation erosion resistance than 0Cr13Ni5Mo stainless steel. The cavitation erosion mechanism of Fe-26Mn-6Si-7Cr-1Cu was studied by examining the eroded surface using X-ray diffraction (XRD) and scanning electron microscopy (SEM). During early stages of cavitation erosion, Fe-26Mn-6Si-7Cr-1Cu alloy undergoes strain induced martensitic transformation. Exposure to further cavitation results in the deformation of ? martensite. The boundaries of ? martensite impede plastic deformation, leading to strain accumulation and subsequent material removal. On the basis of an XRD study and indentation tests, the better cavitaton erosion resistance of Fe-26Mn-6Si-7Cr-1Cu alloy is mainly ascribed to strain induced martensitic transformation, which can absorb impact energy without damage.