Shape memory alloys (SMA) are well-known for their ability to recover a shape change caused by plastic deformation on heating. The probably most widely-used shape memory alloy, near equiatomic NiTi, is operational up to temperatures of about 353 K. Extensive research has been conducted in order to increase the transformation temperatures (TTs) and to allow new applications for example by developing new alloy compositions, viz. Cu-based materials.

At Leibniz IFW Dresden, we are focused on Cu-Al-Ni-Mn (CANM) alloys as a potential counterpart to NiTi-based alloys for high-temperature shape memory applications (beams, bars, plates). CANM shows an improved thermodynamic stability, TTs up to 200°C, a small thermal hysteresis and pronounced shape recovery properties if favorable microstructures are formed. Regarding the microstructure, rapid cooling is often applied during solidification in order to suppress grain growth and to end up in a single-phase, fine-grained state with increased deformability. We have demonstrated that additive manufacturing techniques (laser powder bed fusion – LPBF) with its high intrinsic cooling rates are a powerful tool not only to produce parts with improved and adjustable shape memory behavior, but also to manufacture individually designed parts (lattices, springs) in just a single process step [1-5]. Subsequent heat treatments, as usually required for conventional fabricated counterparts, are not needed.