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%) al loy subjected to different training treatments have been studied in pr esent paper. It has been found that the recovery strain increases sign ificantly through the training treatment of 4% tensile pre-strain foll owed by recovery annealing at 700 degrees C (treatment A) while the re covery strain decreases after the training treatment of 4% tensile pre -strain plus recovery annealing at 300 degrees C (treatment B). The mi crostructures of the alloy after the above training treatments were in vestigated by TEM. It was found that the treatment A favoured the form ation of oriented dislocations and stacking faults which results ii th e improvement of shape memory effect in Fe-Mn-Si alloy.