A Comparison of the Pseudoelastic Performance and Microstructure of the Fe43.5Mn34Al15Ni7.5 Shape Memory Alloy Deposited by Directed Energy Deposition to Conventionally Manufactured Fe43.5Mn34Al15Ni7.5

The unique property of psuedoelasticity makes shape memory alloys (SMAs) very attractive for a variety of engineering applications. Additionally, additive manufacturing (AM) enables near-net shaping of complex shapes while creating distinctive microstructures that can greatly affect the performance of the material. The intersection of SMAs and AM is of increasing research interest due to the interplay of variables and the promising engineering applications of both. In the current study, an Fe_43.5Mn₃₄Al₁₅Ni_7.5 SMA is printed using directed energy deposition (DED). Parameter optimization was performed in order to understand and document the effect of laser power, scan speed, and mass flow rate on the print quality. Additionally, the effect of cyclic heat treatment and aging on the AM microstructure and pseudoelastic response was assessed. Cyclic compression testing to measure the pseudoelastic properties, along with microstructural analysis with scanning electron microscopy were performed on bulk samples in the as-printed and heat-treated conditions. Lastly, the differences in pseudoelastic behavior and microstructure between AM and arc melted samples of the same composition were evaluated.