Evaluation of the Mechanical Performance and Microstructure of Fe43.5Mn34Al15Ni7.5 Shape Memory Alloy Deposited by Directed Energy Deposition

Shape memory alloys (SMAs) have unique properties, like pseudoelasticity, making them very attractive for engineering applications. Additionally, additive manufacturing (AM) can create distinctive microstructures and allows for near-net shaping capabilities. The intersection of SMAs and AM is of increasing research interest due to the unique qualities of each. In the current study, an Fe_43.5Mn₃₄Al₁₅Ni_7.5 SMA is fabricated using directed energy deposition (DED). Due to limited investigation of this alloy with DED, parameter optimization was performed, and the effect of laser power, scan speed, and mass flow rate on the print quality was observed. Additionally, the effect of cyclic heat treatment and aging on the microstructure and mechanical properties was assessed. Compression testing to measure the pseudoelastic properties and microstructural analysis with scanning electron microscopy were performed on bulk samples in the as printed and heat-treated conditions. Lastly, differences in mechanical behavior and microstructure between AM and arc melted samples of the same composition were evaluated.