Measurement of Strain Rate Sensitivity on Transformation Behavior in Fe-based Shape Memory Alloy under Quasi-static Tensile Deformation

Abstract

Fe-based shape memory alloy (Fe-SMA) is attempted to be applied to many engineering fields under different working environments(1) loaded at various deformation rates. Therefore, it is necessary to evaluate an amount of martensite which can control such excellent performances for increasing a reliability of the alloy. However, so far only resistance method can capture the amount of martensite during higher speed of deformation. In this study, the rate sensitivity of volume resistivity in the Fe-SMA is experimentally estimated during tensile tests at various strain rates by using the modified circuit based on Kelvin double bridge from the previous study. Then, the relationship between resistivity and volume fraction of martensite is clarified by X-ray diffraction method.