Superelastic titanium (Ti) alloys are a group of unique functional metallic materials capable of recovering a substantial amount of mechanical strain thereby offering superior resilience. Such strain recovery is significantly greater than that exhibited by conventional elasticity and has been demonstrated to be clearly beneficial and necessary for a vast range of biomedical and dental applications. For example, the age-related physiological deterioration of bones signifies the necessity of employing superelastic implants. Currently, NiTi alloy remains to be the premier choice of superelastic alloys in the broad biomedical sector. However, recently reinforced views on the toxic, carcinogenic and allergenic properties of nickel have resulted in intensified concerns. This has encouraged the design and fabrication of Ni-free superelastic Ti alloys. In addition, enabled by additive manufacturing (AM) or 3D printing, hierarchical micro-architectured lattice meta-materials can exhibit exceptional superelasticity without undergoing phase transformations, upending the conventional perception and unlocking brand-new pathways to exploiting metal superelasticity. This article discusses recent developments in Ni-free superelastic Ti alloys and the determining factors affecting their superelastic recoverable strain. The importance of implant superelasticity relative to the elastic and “superelastic” properties of human bones is examined. Also discussed are the advances in Ni-free Ti-based superelastic alloy design and superelasticity-demanding medical and dental applications. The impact of the AM-enabled micro-architectural design on the development of superelastic structures or superelastic meta-materials is deliberated. Future research priorities are suggested.

超弹性钛（Ti）合金是一组独特的功能性金属材料，能够恢复大量的机械应变，从而提供出色的回弹力。这样的应变恢复显着大于常规弹性所显示的恢复，并且已被证明对于广泛的生物医学和牙科应用是明显有益和必要的。例如，与年龄有关的骨骼生理变坏表明必须使用超弹性植入物。目前，NiTi合金仍然是广泛的生物医学领域中超弹性合金的首选。然而，近来关于镍的毒性，致癌性和变应原性的观点得到了加强，这引起了越来越多的关注。这鼓励了无镍超弹性钛合金的设计和制造。此外，通过增材制造（AM）或3D打印，分层的微体系结构格构超材料可以表现出超强的超弹性，而不会经历相变，颠覆了传统观念，并开辟了利用金属超弹性的全新途径。本文讨论了无镍超弹性钛合金的最新发展以及影响其超弹性可恢复应变的决定性因素。相对于人体骨骼的弹性和“超弹性”特性，研究了植入物超弹性的重要性。还讨论了无镍Ti基超弹性合金设计以及要求超弹性的医学和牙科应用的进展。讨论了启用AM的微体系结构设计对超弹性结构或超弹性超材料的发展的影响。建议未来的研究重点。