Characterization of the microstructures and the shape memory properties of the Fe-Mn-Si-Cr-Ni-C shape memory alloy after severe plastic deformation by differential speed rolling and subsequent annealing
- Department of Materials Science and Engineering, Hongik University, Mapo-gu, Sangsu-dong 72-1, Seoul 121-791 (Korea, Republic of)
- Department of Civil Engineering, Hongik University, Mapo-gu, Sangsu-dong 72-1, Seoul 121-791 (Korea, Republic of)
Highlights: • The Fe-SMA was subjected to severe plastic deformation and then annealed. • Recovery strain increased with increasing grain size. • An optimum grain size existed for the largest recovery stress. • Grain reduction is useful for having a high recovery stress. - Abstract: The Fe-13.51Mn-4.82Si-8.32Cr-3.49Ni-0.15C shape memory alloy was subjected to severe plastic deformation by high-ratio differential speed rolling and subsequent annealing (between 873 and 1373 K) to find the factors that affect recovery stress and recovery strain. As the annealing temperature increased (i. e., as grain size increased), the recovery strain increased. This was attributed to decrease in the density of grain boundaries and the density of twins with increasing grain size. The recovery stress, however, showed a different behavior. It increased with annealing temperature up to 973 K, at which an ultrafine grain size near 1.6 μm was obtained, and then decreased with further increase in the temperature. The difference between the recovery strain and the plastic strain induced by recovery stress under constrained displacement during cooling was proposed to determine the amount of recovery stress. There was an optimum grain size for the largest difference between the recovery strain and the plastic strain. The current study shows that grain-size reduction is not good for having a high recovery strain but it is beneficial for having a high recovery stress in the Fe-Mn-Si shape memory alloys.
- OSTI ID:
- 22832950
- Journal Information:
- Materials Characterization, Vol. 136; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
- Country of Publication:
- United States
- Language:
- English
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