B19-phase transition and related tensile properties of Ti₅₀Ni₃₀Cu₂₀ shape memory alloy doped with hydrogen

Abstract

The B19-phase transition and the related tensile properties of Ti50Ni30Cu20 shape memory alloys were investigated after hydrogen doping. The results revealed that the presence of hydrogen suppressed the B2–B19 transition by decreasing transformation enthalpies. Aging at room temperature lowered martensitic transformation temperature, which might have been associated with the variation of hydrogen contents and states. Ti50Ni30Cu20 shape memory alloys manifested high thermal cycling stability after the aging treatment. In addition, the increase in the hydrogen content was accompanied by an increment in detwinning stress of B19 phase, whereas the elongation of Ti50Ni30Cu20 alloys decreased. Based on our analysis, these effects were caused by the combined activities of different hydrogen states, including those of hydrides and solid-solution hydrogen.

Finite element analysis of hydrogen effects on superelastic NiTi shape memory alloys: Orthodontic application

“…Furthermore, Zuo et al (2016) and Kireeva et al (2017) indicated that even the transformation temperatures would vary with respect to the hydrogen concentration. Besides, it was demonstrated that hydrogen would induce an expansion of the NiTi structure and would provoke residual martensite variants.…”

A coupled model between hydrogen diffusion and mechanical behavior of superelastic NiTi alloys

“…Measurements of differential scanning calorimetry have been performed onNiTi charged with hydrogen [9,10]. The forward transformation ismassively affected compared to the reverse transformation where the transformation temperatures are reduced as the hydrogen amount is increased.…”