Designing Rules of Laser-Clad High-Entropy Alloy Coatings with Simple Solid Solution Phases

Abstract

The criteria of process parameters (µ ≤ 4), atomic size difference (ε ≤ 5.8, δ ≤ 11 and α ≤ 2), thermodynamic (− 14.5 ≤ ∆Hmix ≤ 6.5 and Ω ≥ 1.8) in the prediction of the phase stability for laser-clad high-entropy alloy coatings are studied in detail. Besides, the criteria of valence electron concentration (VEC) applied to distinguish the stability of different solid solution phases are as follows: VEC < 7.65 for simple BCC, VEC ≥ 7.65 for simple face-centered cubic (FCC), 7.14 < VEC < 7.78 for dual-phase BCC and FCC. Among them, µ and ε proposed firstly separate the phase stability of laser-clad high-entropy alloy coatings quite precisely. The other modified criteria (δ, α, ∆Hmix, Ω, VEC) are proved to be different from those of the high-entropy alloys synthesized by the traditional casting and smelting processes.