The effect of the fine-grained, cellular microstructure of additively manufactured Fe-Mn-Si-Cr shape memory alloys on recovery stress

Iron-based shape memory alloys can be seen as an affordable alternative to the well-established Ni-Ti-based alloys. In order to be used in a wider range of applications, functional properties of the iron-based alternative need to be improved. This can be achieved by modifications of the alloy composition and use of improved processing methods. In the present study, three Fe-xMn-6Si-5Cr alloys with different Mn contents ranging from 26% to 31.2% were processed by laser powder bed fusion to analyze the influence of the Mn content and the process-induced microstructure on the shape memory properties. The alloys exhibited a remarkable recovery stress of up to 494 MPa after a 2% tensile pre-strain in the as-built state. Eventually, the unique microstructure resulting from the additive manufacturing process led to increased recovery stresses compared to conventionally processed alloys. Thus, laser powder bed fusion shows great potential for the production of iron-based shape memory alloys for pre-stressing applications.