| Abstract Scope |
Fe-based SMAs are gaining attention for seismic damping in civil structures, where recovery stress is essential for effective prestressing in concrete columns. Recovery stress, the internal stress stored during pre-straining, increases with yield strength, making it a key design target in this work. In this study, a novel Fe-20.2Mn-5.6Si-8.9Cr-5.0Ni-(V,C) alloy was designed to achieve grain size refinement(~10μm) and nano-sized VC precipitation, aiming to enhance yield strength and thereby recovery stress. Detailed analysis using in-situ SAXS and TEM was conducted to examine the growth and distribution of VC precipitates, which are expected to influence recovery stress. Recovery stress was then evaluated by applying tensile pre-straining followed by thermally-induced shape recovery. Through this study, we confirmed that the combined effect of grain refinement and VC precipitation enhances both yield strength and recovery stress. This offers a practical microstructural design strategy that can advance the applicability of Fe-based SMAs, particularly in seismic engineering. |