Effects of Process Parameters on Microsctructure and Superelasticity of L-DED processed Fe-36Mn-9Al-7Ni Shape Memory Alloy

Laser Direct Energy Deposition (L-DED) process is one of the metal additive manufacturing processes that manufactures 3D components using high-power laser to melt metal powder directly onto a substrate. L-DED process has promising advantage that can create complex, high-quality metal components with good dimensional accuracy rapidly. On the other hand, superelastic shape memory alloy (SMA) is an alloy that can recover large deformation to its original shape when the applied load is removed. Superelasticity allows the SMA to withstand cyclic deformations without undergoing permanent deformation, making it an ideal candidate for various applications, including biomedical devices and aerospace components. Among several alloy systems, Fe-Mn-Al-Ni SMA is a promising one due to its low raw material cost and excellent superelastic properties. However, it has been known that to manufacture of the Fe-Mn-Al-Ni SMA using laser-based additive manufacturing process is challenging due to the cracking problems. In this study, Fe-36Mn-9Al-7Ni (wt.%) superelastic SMAs were produced by the L-DED process with various laser parameters. The microstructure and mechanical properties were investigated. We found that a pronounced excellent superelasticity could be obtained from L-DED processed Fe-SMA when the laser process parameters were optimized.