| Composition dependent elastic modulus and phase stability of Ni2MnGa based ferromagnetic shape memory alloys | |
| Q. M. Hu; H. B. Luo; C. M. Li; L. Vitos; R. Yang | |
| 2012 | |
| Source Publication | Science China-Technological Sciences
 |
| ISSN | 1674-7321 |
| Volume | 55Issue:2Pages:295-305 |
| Abstract | Ni2MnGa based ferromagnetic alloys are ideal candidates for applications such as actuators, magnetic refrigerators or magnetostrictive transducers due to their attractive properties such as magnetic field induced shape memory effect and large magnetocaloric effect. The properties of these alloys (e.g., the martensitic transformation temperature T (M) ) sensitively depend on the composition. Understanding the composition dependence of these properties so as to design the alloy as desired is one of the main research topics in this area. In recent years, we have investigated the composition dependent elastic modulus and phase stability of Ni2MnGa-based alloys by using a first-principles method, in hope of clarifying their connection to the properties of these alloys. In this article, we review the main results of our investigations. We show that the tetragonal shear modulus C' is a better predictor of the composition dependent T (M) than the number of valence electrons per atom (e/a) since the general T (M) similar to C' correlation works for some of the alloys for which the T (M) similar to e/a correlation fails, although there exist several cases for which both the general T (M) similar to C' and T (M)similar to e/a correlations break down. Employing the experimentally determined modulation function, the complex 5-layer modulated (5M) structure of the martensite of Ni2MnGa and the Al-doping effect on it are studied. We find that the shuffle and shear of the 5M structure are linearly coupled. The relative stability of the austenite and the martensites is examined by comparing their total energies. The non-modulated martensite beta aEuro(3)aEuro(2) with the tetragonality of the unit cell c/a > 1 is shown to be globally stable whereas the 5M martensite with c/a < 1 is metastable. The critical Al atomic fraction over which the martensitic transformation between the 5M martensite and austenite cannot occur is predicted to be 0.26, in reasonable agreement with experimental findings. |
| description.department | [hu qingmiao; luo hubin; li chunmei; yang rui] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. [li chunmei; vitos, levente] royal inst technol, dept mat sci & engn, se-10044 stockholm, sweden. [vitos, levente] uppsala univ, dept phys, condensed matter theory grp, se-75120 uppsala, sweden. [vitos, levente] res inst solid state phys & opt, h-1525 budapest, hungary.;hu, qm (reprint author), chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china.;qmhu@imr.ac.cn; ryang@imr.ac.cn |
| Keyword | Ni2mnga Martensitic Transformation Elastic Modulus Phase Stability Density Functional Theory Martensitic-transformation Magnetic-properties Heusler Alloys 1st-principles Investigations Crystal-structures Potential Model Approximation Mechanics Behavior Strain |
| URL | 查看原文 |
| Document Type | 期刊论文 |
| Identifier | http://ir.imr.ac.cn/handle/321006/60003 |
| Collection | 中国科学院金属研究所 |
| Recommended Citation GB/T 7714 | Q. M. Hu,H. B. Luo,C. M. Li,et al. Composition dependent elastic modulus and phase stability of Ni2MnGa based ferromagnetic shape memory alloys[J]. Science China-Technological Sciences,2012,55(2):295-305. |
| APA | Q. M. Hu,H. B. Luo,C. M. Li,L. Vitos,&R. Yang.(2012).Composition dependent elastic modulus and phase stability of Ni2MnGa based ferromagnetic shape memory alloys.Science China-Technological Sciences,55(2),295-305. |
| MLA | Q. M. Hu,et al."Composition dependent elastic modulus and phase stability of Ni2MnGa based ferromagnetic shape memory alloys".Science China-Technological Sciences 55.2(2012):295-305. |
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