Ultrasonic cavitation erosion behaviors of high-velocity oxygen-fuel (HVOF) sprayed AlCoCrFeNi high-entropy alloy coating in different solutions

Abstract

In this study, an AlCoCrFeNi high-entropy alloy (HEA) coating was fabricated by HVOF spraying process. The HEA coating was consisted of the BCC phase (Al-rich phase) and FCC phase (Al-poor phase). The BCC phase was main phase. The mechanical performances and corrosion resistances of the coating and 06Cr13Ni5Mo martensitic stainless steel were analyzed in detail. The cavitation erosion behaviors and mechanisms of the HEA coating and 06Cr13Ni5Mo steel were investigated in distilled water and 3.5 wt% NaCl solution. The effects of microstructures, mechanical properties and corrosion properties on cavitation erosion mechanisms were discussed through the observation of eroded surface morphologies. The results showed that the cavitation erosion resistance of the AlCoCrFeNi coating was about 3.5 times that of the 06Cr13Ni5Mo steel in both solutions. In the 3.5 wt% NaCl solution, corrosion damage aggravated cavitation erosion damage, although the enhancement effect of corrosion on cavitation was limited. The corrosion environment did not change the cavitation erosion mechanisms of the two materials. The cavitation erosion mechanism of the HEA coating was lamellar spalling caused by the extension of the interlaminar cracks. Due to the lower plastic deformation resistance, the cavitation erosion mechanism of the 06Cr13Ni5Mo steel was material spalling caused by plastic deformation and fatigue fracture.