Repair of tungsten heavy alloy die casting molds with laser cladded CoCrFeNiWx high entropy alloy Coatings: Microstructure, wear properties and tempering stability

This study investigates the effects of W content on the microstructure and wear properties of CoCrFeNiWx high-entropy alloy coatings prepared on tungsten-heavy alloys by laser melting cladding. The tempering stability of the coatings was also evaluated. The coatings were found to consist of FCC solid solution, W phase, and μ phase. The percentage of W atoms in the μ-phase increased with the increase of W content, resulting in a change in the microstructure. The hardness increases with the increase of W content, while the wear resistance initially increases and then decreases. The coefficient of friction and wear are minimized at x = 0.8. The wear resistance of the CoCrFeNiW0.8 coating is 2.41 times higher than that of the heavy tungsten alloy. After tempering, the coating structure remains stable, and its hardness is higher than that of the heavy tungsten alloy. The wear resistance is also 2.35 times higher.