Laser Treatment of Electrospark-Deposited Ti_0.8W_0.25Cr_0.5FeCo_1.75Ni₃AlB_0.6 High-Entropy Coatings

In the present work, the Ti_0.8W_0.25Cr_0.5FeCo_1.75Ni₃AlB_0.6 (molar ratio) high-entropy alloy (HEA) has been obtained by arc melting. Its phase constituents are two BCC solid solutions, one FCC solid solution and boride with a W₂CoB₂-type crystal structure. The resulting ingot has been used to fabricate electrodes, employed for the electrospark deposition (ESD) of coatings at discharge energies of 0.52 J and 1.1 J. The microhardness of the deposited coatings is about 11 GPa, and their thickness is 25–30 and 30–35 μm at discharge energies of 0.52 and 1.1 J, respectively. The microstructure of the obtained coatings is more homogeneous than that of the cast alloys, and, according to the XRD data, they contain the BCC and FCC solid solutions, as well as a small amount of boride. It has been established that the laser treatment of the coatings facilitates the complete dissolution of boron in the solid solutions and leads to the formation of a heat-affected zone, whereas the hardness of the surface layer remains almost unchanged. The wear resistance of the as-deposited and laser-treated coatings has been investigated.