Hiroaki Otsuka

Pseudoelasticity in an Fe–28Mn–6Si–5Cr shape memory alloy

Abstract Pseudoelasticity (PE) is clearly seen in Fe–28Mn–6Si–5Cr shape memory alloy exhibiting non-thermoelastic martensitic transformation, especially in the sheets hot rolled with a low finishing temperature (FT). Comparison between the temperature dependence of PE and that of shape memory effect (SME) indicates that the γ ⇔ e transformation is responsible not only for the SME but also for the PE. As a result of consideration including variations in 0.2% proof stress and 2.0% flow stress with temperature, it is concluded that PE depends on the amount of the deformation due to the γ → e transformation, the external stress and some temperature-dependent effects which balance against the ‘back stress’ on unloading. Effects of temperature and low-FT hot rolling on PE are discussed on the bases of the above-mentioned factors.

Improvement of shape memory effect due to low-finishing-temperature hot-rolling in an Fe–28Mn–6Si–5Cr alloy

Abstract Shape memory effect in an Fe28Mn6Si5Cr Alloy is improved by lowering the finishing temperature of hot-rolling through a textural effect which was already proved to exist and an additional effect. This latter effect can be attributed to a thermomechanical effect similar to ‘training’.