Wire Direct Energy Deposition of Fe-Mn-Si Shape Memory Alloy Using Cored Wire: Microstructure and Mechanical Analysis

Abstract

This study investigates the feasibility of using cored wire for additive manufacturing of Fe-Mn-Si shape memory alloys by wire direct energy deposition. The manufacturing process in this research is plasma transferred arc in an inert environment.  The samples were characterized in metallurgical and mechanical aspects, including material microstructure, recovery strain, and pseudoelasticity. The distinct characteristic of cored wire (CW) samples was segregation in the inter-dendritic region, which resulted in low ductility, high surface hardness and relatively lower recovery strain compared to the laser powder bed fusion and conventional samples. However, solutionizing and aging heat treatment significantly improved the mechanical behaviour of CW sample including pseudoelasticity and recovery strain. Recovery strain increased from 0.14% to 0.74% after solutionizing and aging heat treatment.

Keywords: Metal Additive Manufacturing, Wire-DED, Shape memory alloy, WAAM, 4D Printing