Comparison of CoCrFeNi coatings prepared via high-speed laser cladding and normal laser cladding on microstructure and properties

Two kinds of CoCrFeNi high entropy alloy coatings were prepared by normal laser cladding (N-) and high-speed laser cladding (HS-), respectively. The comparative analyses of crystallographic orientation distribution, microstructure, microhardness, wear resistance and corrosion resistance of both coatings were conducted. The results show that the phase structures of HS-CoCrFeNi and N–CoCrFeNi coatings are single FCC solid solutions. The dendrite size of HS-CoCrFeNi coating is only half of that of N–CoCrFeNi coating. The microhardness of HS-CoCrFeNi coating (380 HV0.2) is about 2.3 times that of N–CoCrFeNi coating (165 HV0.2), due to the combined effect of grain refinement, dispersion strengthening and dislocation strengthening. The wear resistance and corrosion resistance of HS-CoCrFeNi coating are better than N–CoCrFeNi coating. With the increase of friction speed, the same wear mechanism of the two coatings is obtained, changing from abrasive wear to adhesive wear and fatigue wear. High-speed laser cladding is a promising technology to promote the development and application of high entropy alloys in the industry.