Additive Manufacturing of Fe-Mn-Al-Ni Shape Memory Alloy: Microstructure and Phase Transformation Characteristics

Abstract

Abstract The development of additive manufacturing equipment and the accessibility of metal powders have recently generated considerable interest in the additive production of smart materials, often known as 4D printing. Recent research centered on ternary alloy systems of NiTi. However, iron shape memory alloy (Fe-SMA), which has outstanding superelasticity and consistent superplastic behavior across a wider temperature range, can provide a valuable counterpart for NiTi SMA. However, the viability and impact of manufacturing processing factors on Fe-SMA alloy are not well understood. The current study examines the impact of laser powder bed fusion (LPBF) processing parameters on Fe-Mn-Al-Ni shape memory alloy characteristics such as crack formation, surface roughness, laser-track morphology, density, dimensional accuracy, hardness, and phase transformation. To effectively capture thermal behavior and gather in-situ fabrication data, in-situ monitoring of sample printing was carried out utilizing a unique sensing system made up of a long wave infrared camera throughout a temperature range of −20 °C to 1500 °C. To characterize the microstructure and phase change of the manufactured samples with respect to manufacturing processing parameters, surface roughness testing, gas pycnometer, Vickers hardness testing, and differential scanning calorimetry (DSC) were used. The research showed that volumetric energy densities (VEDs) between 62 and 93 J.mm−3 produce higher-quality materials with fewer defects, which improved the densification and properties of manufactured Fe-SMA (hardness, density, and porosity).