Cold Spray Additive Manufacturing of CoCrFeNiMn High-Entropy Alloy: Process Development, Microstructure, and Mechanical Properties

High-entropy alloys (HEAs) represent a new alloy design paradigm that involves simultaneous mixing of multiple elements in an equimolar or near-equimolar composition to form multi-principal solid solutions with unusual mechanical properties. In this work, CoCrFeNiMn HEA deposits with a near-full density were successfully prepared by a solid-state cold spray additive manufacturing process. In particular, cold spray process conditions such as carrier gas temperature and pressure, particle velocity, and particle size were studied to identify the effective cold spray process window. The as-deposited CoCrFeNiMn HEA deposits are featured by highly heterogeneous and significantly refined grain structures that lead to enhanced micro-hardness compared with conventional cast counterparts. The effects of heat treatment conditions on the microstructure and mechanical properties of the cold-sprayed CoCrFeNiMn HEA deposits are also discussed in order to understand their thermal stability.