The effect of thermomechanical training on the microstructures of Fe-Mn-Si shape memory alloy

The shape memory effect and the microstructures of Fe-30Mn-6Si(wt%) alloy subjected to different training treatments have been studied in present paper. It has been found that the recovery strain increases significantly through the training treatment of 4% tensile pre-strain followed by recovery annealing at 700 C (treatment A) while the recovery strain decreases after the training treatment of 4% tensile pre-strain plus recovery annealing at 300 C (treatment B). The microstructures of the alloy after the above training treatments were investigated by TEM. It was found that the treatment A favoured the formation of oriented dislocations and stacking faults which results in the improvement of shape memory effect in Fe-Mn-Si alloy. (orig.)