Orientation and composition dependencies of shape memory effect IN Fe-Mn-Si alloys

The shape memory effect governed by the γ → e martensitic transformation has been studied in single crystals of several FeMnSi alloys. It has been found that a good shape memory effect appears for the suitable combinations of Mn and Si concentrations in different temperature ranges. Furthermore, it has been shown that a relatively high Mn concentration alloy exhibits a substantial shape memory effect (~30%) with a large temperature hysteresis (~360 K) in contrast to the usual shape memory alloys. By examining surface relieves on an interference microscope and internal structures under an electron microscope, cause of the complete and incomplete shape memory effect has been inquired and discussed on the basis of the selective motion of the Shockley partial dislocations.