Improvement of shape memory effect in Fe–Mn–Si alloy by slight tantalum addition

The effects of slight tantalum (Ta) addition on the microstructures, precipitates, martensitic transformation and shape memory performance of Fe–30Mn–6Si-based alloys were investigated. Experimental results show that the slight Ta addition will increase the c/a ratio of ɛ martensite, reduce the Ms temperature and improve the alloy's shape recovery ability. After TMT at 650 °C, the alloy's Ms temperature is reduced and lots of (Fe, Mn)3Si and TaC precipitates form. The effective nuclei and well-aligned precipitates within the grain interior after TMT will improve significantly the alloy's shape memory performance.