Strain glass transition in Ni47.5+xTi50−xFe2.5 alloys

There have been limited studies on the influence of the Ni/Ti ratio on the strain glass transition behavior in NiTiFe shape memory alloys. In this study, Ni47.5+xTi50−xFe2.5 (x = 0, 0.5, 1.0) alloys were prepared and their microstructural evolution, dynamic mechanical properties, and temperature-dependent electrical resistivity were investigated. We find that increasing Ni/Ti ratio in Ni48.5Ti49Fe2.5 alloy could suppress the long-range martensitic transformation, resulting in the occurrence of strain glass transition characterized by the continuous formation and growth of nanodomains. As a result, a successive softening in elastic modulus and the negative temperature coefficient of electrical resistivity in a broad temperature range have been observed. [Display omitted] •The microstructural evolution of Ni48.5Ti49Fe2.5 alloy is thoroughly investigated.•The formation of nanodomains leads to an electrical resistivity anomaly.•The lattice instability leads to a storage modulus anomaly in Ni48.5Ti49Fe2.5 alloy.•The rising Ni/Ti ratio is beneficial to the strain glass transition.