Investigation on microstructures and properties of Al1.5CoCrFeMnNi high entropy alloy coating before and after ultrasonic impact treatment

Abstract To investigate the effect of plastic deformation with high strain rate on the microstructure and properties of Al1.5CoCrFeMnNi high entropy coating, ultrasonic impact treatment (UIT) was applied on the surfaces of the cladding coatings. According to the results, before and after UIT, the phase composition of Al1.5CoCrFeMnNi cladding coating did not change, remaining FCC and BCC dual-phase structure. Enormous dislocations were produced and accumulated introducing a cumulative strain by severe plastic deformation, forming a gradient structure. Moreover, the impacted layer with a low surface roughness exhibited the higher hardness, plastic deformation resistance and elastic modulus for the grain refinement and the preferred orientation on (1 1 1) crystal plane. But the surface toughness of the impacted specimen was decreased. There is an evident improvement of corrosion resistance for Al1.5CoCrFeMnNi cladding coating after UIT. The application of UIT on high entropy alloy provide a general and efficient method to strengthen the surface of block material.