Recent advances in multicomponent NiTi-based shape memory alloy using metallic glass as a precursor

Recently, concept for an alloy having both glass forming ability and shape memory characteristics has been newly introduced based on the excellent functional properties of existing NiTi alloys. The physical properties of shape memory alloys (SMAs) fabricated through crystallization of glass precursor can be maximized by suppressing the formation of brittle intermetallic compounds and enabling the formation of nanocrystalline structure. The glass precursor is not only applied to small-sized devices easily, but it is possible to produce products with intricate geometry through thermoplastic forming. In addition, the shape memory effect or superelasticity can be manifested after crystallization. In this paper, typical quaternary NiTi-based SMAs and multicomponent NiTibased SMAs fabricated using glass precursor are reviewed. Firstly, quaternary doping effects on the physical properties in NiTiCu and NiTiHf-based alloys, such as shape recovery characteristics, martensitic transformation, and mechanical behaviors, are introduced. Secondly, multicomponent SMA systems using glass precursor fabricated via rapid quenching are introduced. Glass forming ability, crystallization behavior and consequent transformation properties are discussed. SMA applications using glass precursors, including the micro/nanoscale manipulating tools which utilizes the unique shape memory properties, and the surface imprinting based on the super plasticity are introduced.

Automated summary

A new concept has been introduced for an alloy with both glass forming ability and shape memory characteristics, which can enhance the physical properties of shape memory alloys by suppressing the formation of brittle intermetallic compounds and enabling the formation of nanocrystalline structure. The glass precursor is not only suitable for small-sized devices but also allows for production of intricate geometry through thermoplastic forming, with shape memory effect or superelasticity manifested after crystallization. The study reviews typical NiTi-based SMAs and multicomponent SMAs fabricated using glass precursor, discussing the effects of quaternary doping and the properties of multicomponent SMA systems.