Martensitic transformation and shape memory effect of TiZrHf-based multicomponent alloys

Novel superelastic alloys and shape memory alloys composed of multi-principal elements with non-toxic and low magnetic susceptibility were developed. Phase constitution, crystallographic characteristics, mechanical properties, superelasticity and shape memory effect were investigated in Ti–Zr–Hf–Nb–Sn alloys. According to X-ray measurements, compositions exhibiting β phase, α’ phase and α” phase were determined. The lattice parameters of the phases were also determined. Lattice deformation strains were calculated based on the lattice parameters. The Ti–Zr–Hf–Nb–Sn alloys exhibited high tensile strength in a range of 600–1000 MPa. Superelasticity and shape memory effect due to β→α” martensitic transformation and the reverse transformation were observed in the Ti–Zr–Hf–Nb–Sn alloys. Superelastic recovery strain of 2.1% was observed in a (TiZrHf)–8.5Nb–3Sn alloy. The (TiZrHf)–8.5Nb–3Sn alloy exhibited low magnetic susceptibility comparing with alloys applied in medical fields. Potential of large superelastic recovery strain of the alloys was discussed based on the crystallographic and microstructural characteristics.