Melt Spun NiTiHf Ribbons for High Temperature Actuation Applications

High temperature shape memory alloys (HTSMAs) are excellent candidates to extend SMA actuation to automotive, aerospace, and energy applications. From the selection of ternary NiTi based HTSMAs, NiTiHf alloys have gained tremendous traction due to their similar performance and lower costs compared to precious metal analogues. While these material systems have been highly successful in lab environments, manufacturing at scale presents a set of unique challenges such as controlled casting and low throughput. Furthermore, minimizing Hf content to lower cost is crucial for competitive commercialization. The current work investigated rapid quenching of molten NiTiHf via melt spinning, providing high throughput ribbons with homogeneous microstructures, and compositions. In addition to thermomechanical treatments, we demonstrate that the Multiple Memory Material process can be implemented to drastically increase local transformation temperatures while maintaining bulk material Hf content. This results in a cost-effective solution to fabricate NiTiHf HTSMA.