Thermal stress and local crystallization parameters in single-crystal rods of Ni-Mn-Ga ferromagnetic shape memory alloys
| Autor: | S. Hemes, E. Pagounis, H. Behnken, M. Laufenberg |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Condensed matter physics 02 engineering and technology Crystal structure Shape-memory alloy 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Rod law.invention Inorganic Chemistry Ferromagnetism Magnetic shape-memory alloy law Condensed Matter::Superconductivity Lattice (order) 0103 physical sciences Materials Chemistry Crystallization 0210 nano-technology Single crystal |
| Zdroj: | Journal of Crystal Growth. 534:125485 |
| ISSN: | 0022-0248 |
| DOI: | 10.1016/j.jcrysgro.2020.125485 |
| Popis: | Ni-Mn-Ga single crystal material shows a strong magnetic shape memory (MSM) effect with reversible strains of up to 12%. Single crystal rods of up to 40 mm diameter are produced in Bridgman type processes. For actuator applications small sticks are cut out of the rods. The magneto-mechanical performance of these sticks depends among other parameters on their alignment with the crystal lattice. Thus, each inhomogeneity of lattice orientation within the rod reduces the achievable yield. The lattice orientation within the single crystal rods usually differs slightly between bottom and top region, and it shows local scattering due to misorientations between the growing dendrites. In the present study the macroscopic thermal stresses induced during the crystallization process are simulated. It is found that these stresses do not affect the crystal orientation. However, they may lead to shape changes of the single crystal rod. |
| Databáze: | OpenAIRE |
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