First-principles investigation of the composition dependent properties of Ni(2+x)Mn(1-x)Ga shape-memory alloys

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	First-principles investigation of the composition dependent properties of Ni(2+x)Mn(1-x)Ga shape-memory alloys
	C. M. Li; H. B. Luo; Q. M. Hu; R. Yang; B. Johansson; L. Vitos
	2010
发表期刊	Physical Review B
ISSN	1098-0121
卷号	82 期号:2
摘要	The composition dependent lattice parameter, phase stability, elastic moduli, and magnetic transition temperature of the Ni(2+x)Mn(1-x)Ga shape-memory alloys are studied by using the first-principles exact muffin-tin orbital method in combination with the coherent potential approximation. The lattice parameter and tetragonal shear modulus of the cubic L(21) austenite phase decreases linearly with increasing concentration x of excess Ni atoms. The heats of formation of both cubic L(21) and tetragonal beta''' phases and their difference increase with x, indicating decreasing stability of the cubic and tetragonal phases and increasing driving force for the L(21) to beta''' martensitic transition. Investigating the electronic density of states, we find that the Ni-induced decreasing phase stability can mainly be ascribed to the weakening of the covalent bonding between minority spin states of Ni and Ga. Using the computed parameters, the composition dependence of the martensitic transition temperature is discussed. The theoretical Curie temperature, estimated from the Heisenberg model in combination with the mean-field approximation, is larger for the beta''' phase than for the L(21) phase. For both phases, the Curie temperature decreases nearly linearly with increasing x.
部门归属	[li, chun-mei; luo, hu-bin; hu, qing-miao; yang, rui] chinese acad sci, inst met res, shenyang natl lab mat sci, shenyang 110016, peoples r china. [li, chun-mei; hu, qing-miao; johansson, borje; vitos, levente] royal inst technol, dept mat sci & engn, se-10044 stockholm, sweden. [johansson, borje; vitos, levente] uppsala univ, dept phys, condensed matter theory grp, se-75121 uppsala, sweden. [johansson, borje] dalian univ technol, sch phys & optoelect technol, dalian 116024, peoples r china. [johansson, borje] dalian univ technol, coll adv sci & technol, dalian 116024, peoples r china. [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, 72 wenhua rd, shenyang 110016, peoples r china;qmhu@imr.ac.cn
关键词	Ni-mn-ga Exchange Interactions Ferromagnetic Metals Phase-transformation Electronic-structure Martensitic Phase Potential Model Ni2mnga Approximation Temperatures
URL	查看原文
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/31204
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	C. M. Li,H. B. Luo,Q. M. Hu,et al. First-principles investigation of the composition dependent properties of Ni(2+x)Mn(1-x)Ga shape-memory alloys[J]. Physical Review B,2010,82(2).
APA	C. M. Li,H. B. Luo,Q. M. Hu,R. Yang,B. Johansson,&L. Vitos.(2010).First-principles investigation of the composition dependent properties of Ni(2+x)Mn(1-x)Ga shape-memory alloys.Physical Review B,82(2).
MLA	C. M. Li,et al."First-principles investigation of the composition dependent properties of Ni(2+x)Mn(1-x)Ga shape-memory alloys".Physical Review B 82.2(2010).