Phase stability of Ni-2(Mn1-xFex)Ga: A first-principles study

IMR OpenIR

	Phase stability of Ni-2(Mn1-xFex)Ga: A first-principles study
	H. B. Luo; Q. M. Hu; C. M. Li; R. Yang; B. Johansson; L. Vitos
	2012
发表期刊	Physical Review B
ISSN	1098-0121
卷号	86 期号:2
摘要	Ni-2(Mn1-xFex)Ga ferromagnetic shape memory alloy shows unusual composition-dependent martensitic transformation temperature (T-M), namely, T-M decreases with increasing e/a ratio. In hope of understanding this unusual behavior, we investigated the composition dependence of the heat of formation (H-f) and shear elastic modulus (C') of the cubic austenite as well as the stability of the five-layer modulated (5M) tetragonal martensite relative to the austenite, using first-principles exact muffin-tin orbital method in combination with coherent potential approximation. Our calculations demonstrated that H-f of the austenite increases with the Fe content x. C' increases slightly with x up to 0.05 but decreases thereafter. The composition dependence of both H-f and C' cannot fully account for the trend of T-M against x although such correlations have been proposed in literature for other Ni-Mn-Ga based alloys. The structure of 5M martensite phase of Ni-2(Mn1-xFex)Ga with 0 < x < 0.2 is determined by optimizing both the shear (changing c/a) and wavelike shuffle of atoms in (110) planes along [1 (1) over bar0] direction adopting the experimentally determined modulation function. The energy difference Delta E-AM between the austenite and 5M phases decreases with increasing x up to 0.05, following the lower Delta E-AM corresponding to lower T-M rule. However, with x larger than 0.05, Delta E-AM increases, against the experimental T-M similar to x behavior. We propose that, if taking the temperature effect and the spin-orbital coupling into account, the Delta E-AM similar to x curve might be altered and may explain the unusual composition dependence of Ni-2(Mn1-xFex)Ga.
部门归属	[luo, hu-bin; hu, qing-miao; li, chun-mei; yang, rui] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. [johansson, borje; vitos, levente] royal inst technol, dept mat sci & engn, se-10044 stockholm, sweden. [vitos, levente] uppsala univ, div mat theory, dept phys & astron, se-751210 uppsala, sweden. [vitos, levente] wigner res ctr phys, 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, 72 wenhua rd, shenyang 110016, peoples r china.;qmhu@imr.ac.cn
关键词	Ni-mn-ga Shape-memory Alloys Field-induced Strain Magnetic-properties Martensitic-transformation Crystal-structures Heusler Alloys Potential Model Ni2mnga Approximation
URL	查看原文
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/60143
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	H. B. Luo,Q. M. Hu,C. M. Li,et al. Phase stability of Ni-2(Mn1-xFex)Ga: A first-principles study[J]. Physical Review B,2012,86(2).
APA	H. B. Luo,Q. M. Hu,C. M. Li,R. Yang,B. Johansson,&L. Vitos.(2012).Phase stability of Ni-2(Mn1-xFex)Ga: A first-principles study.Physical Review B,86(2).
MLA	H. B. Luo,et al."Phase stability of Ni-2(Mn1-xFex)Ga: A first-principles study".Physical Review B 86.2(2012).