Cold‐Casting Based Process Development of NiTiHf High Temperature Shape Memory Alloys for Binder Jet Additive Manufacturing

NiTi‐based shape memory alloys (SMAs) are valued for their excellent thermo‐mechanical properties, but binary NiTi loses functionality at elevated temperatures. To overcome this limitation, high‐temperature SMAs, such as NiTiHf, have attracted interest for their enhanced strength and stable superelasticity in demanding environments. This work explores, for the first time, the development of postprocessing conditions for NiTiHf alloys intended for binder jetting additive manufacturing (BJAM). A cold‐casting‐based methodology was employed to emulate the BJAM process and systematically identify critical postprocessing conditions before full‐scale AM. Another aspect of this study is the use of a bimodal powder system designed to mitigate contamination by increasing surface area and improving powder packing, a beneficial approach for future BJAM processing of SMAs. By systematically tuning curing, debinding, and sintering parameters, processing conditions that maximize densification and phase homogeneity are identified. The optimized alloys show consistent transformation and densification behavior, confirmed by relative density, differential scanning calorimetry, optical and scanning electron microscopy, and elemental analysis. These findings provide a preliminary processing framework for future BJAM fabrication of NiTiHf components, thereby supporting the continued development of high‐performance SMAs for demanding applications.