Additive manufacturing of shape memory alloys: A review with emphasis on powder bed systems

The ability of shape memory alloys (SMAs) to recover inelastic strains larger than any other metallic alloy has prompted their use in a wide range of applications. However, for the most common SMAs, including NiTi and Cu-based systems, fabrication using conventional means raises important challenges, including poor workability and potentially high tool wear. Additive manufacturing offers a direct answer to these challenges by eliminating the need for tooling and allowing the production of samples of complex geometries directly from computer-aided designs. The present work provides a comprehensive review of additive manufacturing applied to various SMA systems, with focus on the influence of process parameters and heat-treatment on the microstructure, printability, and the structural and functional behavior of additively fabricated samples.