Effect of CeO₂ Addition on Microstructure and Properties of Iron-Based Shape Memory Alloys by Arc Additive Manufacturing

Fe-14Mn-6Si-9Cr-5Ni iron-based shape memory alloys with different mass fractions (0, 1%, 2%, 3%) of CeO₂ were prepared by powder core wire + arc additive manufacturing technique, and the effects of CeO₂ additions on the microstructure and shape memory properties of the alloy were studied. The results show that after adding 1 wt% CeO₂, the precipitated phase in the alloy was reduced, the rare earth compounds in large size were precipitated at the grain boundary, and the microstructure was uniform. At this time, there were no transgranular growth ε martensite and a few crossing martensite were observed after bending deformation. When the mass fraction of CeO₂ increased to 2% and 3%, the precipitated phase increased, and the distribution uniformity became worse. At this time, the transgranular growth ε martensites and crossing martensite increased after bending deformation. With the increase of CeO₂ addition, the grain size of the test alloy decreased, the probability of stacking fault increased, and the shape recovery rate first increased and then decreased. When the CeO₂ mass fraction was 1%, the grain size was relatively small, the probability of stacking fault was relatively large, and the shape recovery rate was the largest, the shape memory property was best.