Adapting Fe-Mn-Si-Cr shape memory alloy for laser powder bed fusion by adjusting the Mn content

Shape memory alloys (SMA) are functional materials exhibiting the shape memory effect. Conventional standard manufacturing technologies for shape memory alloys include melting, casting, and forming. These often require additional machining steps to achieve the final component shape, limiting the geometric design. The production of SMAs using additive manufacturing technologies opens up new possibilities, but research has been limited, especially for iron-based SMAs. The present study investigated whether an iron-based SMA alloy powder suitable for the additive manufacturing process can be produced via atomization and subsequently 3D printed with laser powder bed fusion (PBF-LB/M). Two FeMnSi SMAs with varying manganese contents of 23.6% and 28.5% were successfully atomized and laser processed. The effect of the manganese content on the shape memory characteristics was investigated by means of dilatometry. A 5 wt% change in manganese content was found to impact the onset of the keyhole fusion mode for PBF-LB/M as well as the resulting shape memory characteristics. Reduced manganese content is shown to enhance the shape memory effect of FeMnSi.