Effect of annealing temperature on microstructure and memory properties of Fe-Mn-Si-Cr-Ni alloy prepared by additive manufacturing

The influence of annealing treatments at 600°C, 750°C, and 900°C on the alloy structure and memory properties was investigated in this study using a powder-core wire fusion-deposited Fe-14Mn-6Si-9Cr-5Ni alloy, accompanied by a preliminary analysis of the effects of annealing temperature. The results show that compared with the alloy annealed at 600°C, the alloy annealed at 750°C has less crossover of cooling martensite, resulting in improved ordering of stress-induced martensite during pre-deformation, and consequently, enhanced memory properties. At 900°C, ferrite almost completely decomposed, promoting martensitic growth through the crystal, which sharply decreased the memory properties, only slightly better than those of the unannealed alloy. It can be seen that annealing at the appropriate temperature can regulate the morphology and amount of cooling martensite in the additively manufactured Fe-Mn-Si-Cr-Ni alloy, thus improving the memory properties. However, excessively high annealing temperatures can cause excessive decomposition or even disappearance of δ-ferrite, which stabilizes the grain boundaries, thus adversely affecting the memory properties of the alloy.