Shape memory alloys (SMA) are a subgroup of active materials, which have unique thermo-mechanical response. SMA exhibits two primary characteristics – Shape Memory effect (SME) and superelasticity (SE). The former refers to materials which can deform and return to their pre-deformed shape when heated, while the latter refers to large reversible strains – between 6%-10% upon a loading-unloading cycle. SMA are promising materials for numerous innovative applications in the fields of actuation, sensing, elastocaloric cooling, energy harvesting and energy absorption. Due to manufacturing difficulties, SMA are currently available in limited simple geometries, such as wires, rods and thin plates. This limitation hinders the development of SMA-based applications that require complex geometries. Additive manufacturing (AM) is a solution to this problem.
In this work, we want to show for the first time the feasibility of an innovative solid-state AM technology for fabricating NiTi SMA. The technology, called MoldJet, was developed recently by Tritone Technologies Ltd., an Israeli based company, and implemented to produce structural metals and alloys. The term solid-state implies that the feedstock remains solid during the printing process, thus allowing better microstructure control of the printed part. This contrasts conventional fusion-based additive manufacturing methods, such as LBPF or EBM, where the material is repeatedly melted and solidified.
