Iron-based superelastic alloys with near-constant critical stress temperature dependence
Ji Xia, Y. Noguchi, Xiao Xu, Takumi Odaira, Yuta Kimura, Makoto Nagasako, Toshihiro Omori, Ryosuke Kainuma
Abstract
Shape memory alloys recover their original shape after deformation, making them useful for a variety of specialized applications. Superelastic behavior begins at the critical stress, which tends to increase with increasing temperature for metal shape memory alloys. Temperature dependence is a common feature that often restricts the use of metal shape memory alloys in applications. We discovered an iron-based superelastic alloy system in which the critical stress can be optimized. Our Fe-Mn-Al-Cr-Ni alloys have a controllable temperature dependence that goes from positive to negative, depending on the chromium content. This phenomenon includes a temperature-invariant stress dependence. This behavior is highly desirable for a range of outer space-based and other applications that involve large temperature fluctuations.