Selective laser melted high Ni content TiNi alloy with superior superelasticity and hardwearing

• High quality Ti 47 Ni 53 alloy is fabricated by the SLM for the first time. • The microstructure of SLM-Ti 47 Ni 53 alloy has been systemically studied. • Compressive deformation behavior is explored by the in-situ HE-XRD. • Synergy relationship between transforming matrix and elastic Ni 4 Ti 3 is revealed. • This work is a favorable reference for preparing other high Ni content TiNi alloys. TiNi alloys with high content Ni (52–55 at.%) are perfectly suitable for preparing wear- and corrosion-resistant parts that service on the space station, spacecraft, and submarine, because of their superior superelasticity, high strength, and hardwearing. However, the fabrication of complicated Ni-rich TiNi parts by the traditional machining method often faces problems of poor precision, low efficiency, and high cost. In this work, we succeed in preparing an excellent Ti 47 Ni 53 alloy by selective laser melting (SLM), and thus, open a new way for the efficient and precise formation of complicated Ni-rich TiNi parts with superelasticity and hardwearing. An optimized processing window for compact parts without defects is reported. The elaborately fabricated Ti 47 Ni 53 alloy exhibited a breaking strain of 11%, a breaking stress of 2.0 GPa, a superelastic strain of 9%, and a better hardwearing than that of casting and quenched Ti 47 Ni 53 alloy. Besides, the microstructure, phase transformation, and deformation, as well as their influence mechanisms are investigated by in situ transmission electron microscope (TEM) and high-energy X-ray diffraction (HE-XRD). The results obtained are of significance for both fundamental research and technological applications of SLM-fabricated high Ni content TiNi alloys.