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First-principles study on the effect of Hf content onmartensitic transformation temperatureof TiNiHf alloy 总被引:1,自引:0,他引:1
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In this paper a first-principles study of the electronic structure and stability of B2
TiDFT TiNiHf 电子结构 马氏体转化温度 平面波 DFT, TiNiHf, electronic structure, martensitic
transformation temperature Project supported by the National Natural Science Foundation of China
(Grant No 50471018). 3/3/2006 12:00:00 AM 6/7/2006 12:00:00 AM In this paper a first-principles study of the electronic structure and stability of B2 Ti1-xNiHfx (x = 0.2, 0.4, 0.6) and B19′ Ti1-xNiHfx(x = 0, 0.5) alloys is presented. The calculations are performed by the plane-wave pseudopotential method in the framework of the density functional theory with the generalized gradient approximation. This paper calculates the lattice parameters, density of states, charge density, and heats of formation. The results show that the electronic structure and stability of B2 Ti1-xNiHfx change gradually with Hf content. However, Hf content has little effect on the electronic structure and stability of B19′ Ti1-xNiHfx. The mechanism of the effect of Hf content on martensitic transformation temperature of TiNiHf alloys is studied from the electronic structure. 相似文献
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The effect of Fe on the martensitic transformation of TaRu high-temperature shape memory alloys:A first-principles study
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The effect of Fe on the martensitic transformation of TaRu high-temperature shape memory alloys has been investigated using first-principles calculations. The site preference of Fe in TaRu alloys has been clarified for the first time, and the results show that Fe is predicted to occupy Ru sites. The addition of Fe increases the stability of the Ta50Ru50-xFex β phase, leading to a significant decrease in the β to β′ martensitic transformation temperature. In addition, the mechanism of the Fe alloying effect is explained on the basis of the electronic structure. 相似文献
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Combined experimental and theoretical study on the effect of Nb content on martensitic transformation of NbRu shape memory alloys
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The effect of Nb content on the martensitic transformation
of NbRu high-temperature shape memory alloys is investigated by
experiments and first-principles calculations. We calculate the
lattice parameters, density of states, charge density, and heats of
formation of Nb50+xRu50-x β phase. The
results show that an increase in Nb content increases the stability
of Nb50+xRu50-x β phase, leading to a
significant decrease of the β to β' martensitic
transformation temperature. In addition, the mechanism of the
effects of Nb content on phase stability and martensitic
transformation temperature is studied on the basis of
electronic structure. 相似文献
4.
Effect of Co on magnetic property and phase stability of Ni--Mn--Ga ferromagnetic shape memory alloys: A first-principles study
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The effect of Co content on magnetic property and phase stability of Ni50-xMn25Ga25Cox ferromagnetic shape memory alloys has been investigated using first-principles calculations. The total energy difference between paramagnetic and ferromagnetic state of austenite plays an important role in the magnetic transition. The high Curie temperature can be attributed to the stronger Co-Mn exchange interaction as compared to the Ni-Mn one. The phase stability of Ni50-xMn25Ga25Cox austenite increases with increasing Co content, which is discussed based on the electronic structure. 相似文献
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为了解雄县地区地下水水化学特征及水质现状,选取43组地下水,采用仪器分析和容量法相结合的方式对雄县地下水典型的环境项目进行测定,运用数理统计和三元相图分析了雄县地下水的主要离子特征,并运用综合评价法对地下水质量予以评价。结果表明,该类指标的方法检出限为0.001~1.30mg/L,相对标准偏差为0.30%~3.7%,pH值和偏硅酸空间变异最低(CV30%),Mg~(2+)、Cl~-、SO_4~(2-)和碘化物的空间变异性最高(CV100%),水化学类型主要以HCO_3-Na型为主,水质评价结果显示研究区域地下水水质总体状况较好,多为Ⅱ类水和Ⅲ类水。研究成果对了解雄县地下水水质现状具有重要意义。 相似文献
6.
Microstructural,phase transformation and magnetic properties of Ni-Mn-Ga alloy fabricated by spark plasma sintering
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The microstructural,phase transformation and magnetic properties of Ni-Mn-Ga alloy fabricated using the spark plasma sintering method have been investigated. The results show that both the as-sintered and annealed sintered specimens exhibit typical martensitic transformation behaviours. The martensite of the sintered specimen after annealing exhibits a ferromagnetic nature. Moreover,study of the fracture surface indicates that the transgranular fracture contributes to the higher ductility of sintered Ni-Mn-Ga alloy. In addition,the transformation strain in sintered Ni-Mn-Ga alloy is studied for the first time. 相似文献
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