Abstract
A nominally new Fe-16Mn-5Si-10Cr-4Ni-1(V, N) (mass %) alloy containing V and N has been developed aiming to precipitate VN particles without training. Transmission electron microscope (TEM) observations have indicated that VN preferentially precipitated on the top of stacking faults and act as nucleation sites for the γ (FCC) →ε phase (hcp) transformation. VN plays a key role in improving the thermo-mechanical properties. The results showed that shape memory properties could be remarkably improved by pre-deformation at room temperature before aging or deformation at low temperature after aging treatment. 44% shape recovery and 440 MP shape recovery stress were achieved when heating to 160 °C after the initial 4% strain at RT. Nearly perfect shape recovery (90%) and shape recovery stress (500 Mpa) have been achieved when the alloy was 4% deformed at −45 °C followed by heating up to 225 °C. Moreover, no relaxation phenomena were found when the tested samples were cooled to room temperature. All of these results suggested the possible practical applications of Fe–Mn–Si SMAs, especially in smart civil engineering.
Published Version
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