In-situ TEM observation of ε→γ transformation during heating in an Fe-Mn-Si shape memory alloy

In-situ TEM observation of the deformed specimen on heating from R.T. up to 873 K in an Fe-30.3 mass%Mn-6.1 mass%Si shape memory alloy has been performed, It is found that the thicker epsilon-martensite plates will be disintegrated layer by layer through the reverse motion and annihilation of partial dislocations and the last induced epsilon-martensite will be the first to disappear. The in-situ observations on heating of the secondary deformed specimen after once thermomechanical cycling has also been conducted, from which the improvement mechanism of thermo-mechanical training can be well explained.