Effect of Cerium Addition on the Microstructure and Shape Memory Properties of Austenitic Fe–Mn–Si–Cr–Ni Alloys

Abstract

The addition of rare earth elements, such as cerium, to austenitic Fe–Mn–Si‐based shape memory alloys has been shown to improve both corrosion resistance and shape recovery. However, the mechanisms underlying the effect of Ce on shape recovery are still unclear. This study investigates the influence of the addition of small amounts of Ce (0.18, 0.42, and 0.96 wt%) on the microstructure and shape recovery of an austenitic Fe–13.50Mn–3.98Si–9.54Cr–4.51Ni alloy. Ce additions induce the formation of a large number of Ce‐rich particles, which act as austenitic grain refiners. Both grain refinement and the formation of Ce‐rich particles contribute to the strengthening of the matrix at 0.42 wt% Ce addition. In addition, Ce additions alter the MS temperature, which increases with Ce additions. Total shape recovery improves with 0.18 and 0.42 wt% Ce additions, but decreases with 0.96 wt% Ce addition. The beneficial effect of Ce addition in improving the shape recovery of the austenitic Fe–Mn–Si–Cr–Ni alloy is related to the enhancement of the elastic shape recovery component of the total shape recovery. However, the shape memory recovery due to the shape memory effect always decreases with the increase of the Ce content.