Phase evolution, microstructure, microhardness and corrosion performance of CoCrFeNiNb_x high entropy alloy coatings on 316 stainless steel fabricated by laser cladding

Abstract

FeNiCoCrNb x (x: molar ratio, x = 0, 0.1, 0.2, 0.3) high entropy alloy coatings (HEACs) were fabricated on 316 stainless steel (SS) by laser cladding (LC). Experimental results showed that the addition of Nb increased the lattice constant of FeNiCoCrNb high entropy alloy system. HEAC exhibited the transformation from columnar crystal at the interface to equiaxed crystal at the surface on the cross-sectional plane because of the change in the temperature gradient (G) and solidification rate (R). When x = 0.3, lamellar Laves phases appeared in ID. The microhardness of the four HEACs was 1.78, 2.19, 2.30 and 2.37 times that of 316 SS. The HEAC with x = 0.3 as well as 316 SS exhibited typical p-type semiconductor characteristics, which showed excellent corrosion resistance as indicated by the lowest I corr of 2.46 × 10 −9 A cm −2 and a larger passivation region with 2 times that of 316 SS.

Design and Effect of Resonant Ultrasonic Vibration-Assisted Laser Cladding (R-UVALC) on AlCrFeMnNi High-Entropy Alloy

“…Presently, a multitude of High-entropy Alloy (HEA) coatings are employed in the process of laser cladding onto 304 steel. The coatings mentioned include AlCoCrFeNiNbx [ 33 ], FeCoNiCrMnTi [ 34 ] Al x CoCrFeNi [ 35 ], Fe 50 Mn 30 Co 10 Cr 10 [ 36 ], FeCrFeNiNb x [ 37 ], FeNiCoCrMo x [ 38 ], and AlCoCrFeNi [ 39 ]. The application of laser-clad HEA coatings has demonstrated substantial scientific significance in enhancing the surface characteristics of stainless-steel substrates.…”