Experimental behavior of iron-based shape memory alloys under cyclic loading histories

The present paper investigates the behavior of iron-based shape memory alloys (Fe-SMAs) subjected to cyclic inelastic straining by means of uniaxial coupon experiments. The tests feature round bar coupons subjected to a broad range of uniaxial cyclic strain histories representative of earthquake loading. The experimental results suggest that the Fe-SMA under investigation exhibits an asymmetric stress-strain relation, with limited superelastic behavior. It was found that the post-yield/phase transformation behavior of the Fe-SMA alloy is both strain-rate and temperature-dependent. Quantitative comparisons with structural steels subjected to nominally identical cyclic strain histories indicate that, although the studied Fe-SMA has a similar energy dissipation per loading excursion with respect to conventional S355J2+N, the Fe-SMA’s hardening response is appreciably higher, leading to comparatively larger elastic strain energies being stored.