Evolution of the microstructure and properties of laser-clad FeCrNiCoB_x high-entropy alloy coatings

Abstract

FeCrNiCoB_x high-entropy alloy coatings were prepared by laser cladding, and the effects of boron addition on the microstructure, hardness and corrosion resistance of the coatings were studied. Results showed that the coatings comprised a simple FCC solid solution with boride precipitation. When 0.5 ≤ x ≤ 1.0, (Cr, Fe)₂B with an orthorhombic structure was found in the coatings, and the hardness and corrosion resistance of the coatings were enhanced by increasing boron content. As x approached 1.25, the borides changed from orthorhombic (Cr, Fe)₂B to tetragonal (Fe, Cr)₂B, which deteriorated the corrosion resistance of the coatings. Stacking faults found in (Cr, Fe)₂B may be caused by the phase transformation of borides.

Keywords:

• High-entropy alloy
• Laser cladding
• Corrosion
• Borides
• Phase transformations

Acknowledgments

The authors gratefully acknowledge the financial support from the Natural Science Foundation of Fujian Province, China (No. 2012J01202) and the Research Foundation of Education Bureau of Fujian Province, China (No. JA11179).