Micromechanical Insights into Sinter‐Based Additively Manufactured NiTi with Nb as a Sintering Aid

The combination of active materials with complex geometries, as enabled by additive manufacturing techniques, facilitates access to unprecedented mechanical responses. Among different printing methods, filament‐based materials extrusion (f‐MEX) grants extraordinary design freedom for a wide range of metals. Yet, the final properties are often corrupted by poor sintering behavior. Current filament compositions are tailored toward performance improvement via polymeric additives, but the effect of metallic additives remains to be fully explored. This work studies the microstructural and micromechanical impact of incorporating Nb as a liquid‐phase sintering aid to NiTi shape memory alloys printed via f‐MEX. Printed and sintered systems are compared to bare sintered powders via chemically correlated nanoindentation to investigate the effect of the filament binder on the final properties. Nanoindentation mapping highlights the intricate microstructure influenced by the addition of Nb. Inhomogeneities from the as‐received powder still remain due to the short sintering times, which hinder complete diffusion of Nb into the NiTi matrix. This work demonstrates the microstructural and micromechanical integrity of NiTiNb parts produced via f‐MEX, proving liquid sintering a reliable alternative for sintering these promising alloys and making them suitable for engineering applications at a lower processing energy expense.