Preparation of High Entropy Alloys Without Pre-Alloying, Using Laser Melt Deposition (LMD) Technique

This study explores the fabrication of an equimolar CoCrFeNi high-entropy alloy (HEA) using laser metal deposition (LMD) technique on a 316 L austenitic stainless steel substrate, without pre-alloying. Elemental metal powders were mixed in a planetary ball mill and directly deposited to investigate the effect of layer number on alloy composition and substrate intermixing. Experimental results revealed significant dilution in the first four layers, with substrate intermixing affecting composition. The coarse-grained crystal structure observed in the initial layers persisted in subsequent layers, and hardness measurements indicated the cumulative thermal effects of sequential deposition. From an industrial perspective, this approach offers a cost-effective and flexible manufacturing strategy, eliminating the need for pre-alloying. Moreover, gradient compositional layers can be achieved, enabling tailored material properties. This work demonstrates the feasibility of producing multi-layer HEAs directly from elemental powders while addressing the challenges of compositional stability.