Strengthening of Fe-Mn-Si Based Shape Memory Alloys by Grain Size Refinement

Degree of the shape memory effect was measured either by bending, tensile and compression tests in the temperature range 77∼300 K. The yield stress increased substantially by the grain size refinement, yet maintaining a good shape memory effect. In addition to usual mentioned slow strain rate tests ( about 10 -3 s -1 ), shape deformation was given at high strain rate ( 10 3 s -1 ) by hammering, in order to induce fine structure. It is also found that the shape memory effect under an opposing force was improved by the high-speed deformation.