Cavitation Erosion Performance and Phase Transformation Strengthening Behavior of Laser Clad Iron-Based Shape Memory Alloy Coatings

The extended service life of overcurrent components often leads to surface the cavitation erosion damage, prompting current research efforts to focus on coating reinforcement for extending their operational lifespan. The present study employed analytical techniques, to investigate the cavitation erosion performance of laser clad Fe-Mn-Si-Cr-Ni shape memory alloy (SMA) coatings with focus on the enhancing mechanism of their martensitic phase transformation. The results indicated that laser cladding could produce high-quality SMA coatings, free of defects such as pores and cracks, resulting in a significant improvement in the cavitation erosion performance. After 300 min of the cavitation, the coated samples remained in the cavitation erosion incubation stage, demonstrating an accumulated mass loss rate of approximately 0.002 mg/min, merely 13% of that observed in the matrix samples. Extensive microstructural delamination occurred in the matrix samples after 300 min of the cavitation, whereas the coated samples exhibited only "shear bands" formed by plastic deformation on the surface. The martensitic phase transformation from γ-austenite to ε-martensite served to dissipate the stress induced by cavitation bubble collapse on one hand, and, on the other hand, the robust nature of martensite produced a hardening effect, significantly enhancing the cavitation resistance of the coating.