期刊文献+
共找到82,192篇文章
< 1 2 250 >
每页显示 20 50 100
A first-principle calculation of structural,mechanical and electronic properties of titanium borides 被引量:3
1
作者 闫海燕 魏群 +1 位作者 常少梅 郭平 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第7期1627-1633,共7页
The first-principle calculations are performed to investigate the structural,mechanical and electronic properties of titanium borides (Ti2B,TiB and TiB2).Those calculated lattice parameters are in good agreement wit... The first-principle calculations are performed to investigate the structural,mechanical and electronic properties of titanium borides (Ti2B,TiB and TiB2).Those calculated lattice parameters are in good agreement with the experimental data and previous theoretical values.All these borides are found to be mechanically stable at ambient pressure.Compared with parent metal Ti (120 GPa),the larger bulk modulus of these borides increase successively with the increase of the boron content in three borides,which may be due to direction bonding introduced by the boron atoms in the lattice and the strong covalent Ti-B bonds.Additionally,TiB can be regarded as a candidate of incompressible and hard material besides TiB2.Furthermore,the elastic anisotropy and Debye temperatures are also discussed by investigating the elastic constants and moduli.Electronic density of states and atomic Mulliken charges analysis show that chemical bonding in these titanium borides is a complex mixture of covalent,ionic,and metallic characters. 展开更多
关键词 titanium borides first-principle calculations mechanical properties density of states Mulliken atomic population analysis
下载PDF
A Comparative Study of Elastic Constants of NiTi and NiAl Alloys from First-Principle Calculations 被引量:2
2
作者 Jianmin Lu Qingmiao Hu Rui Yang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2009年第2期215-218,共4页
To investigate the origin of the strong dependence of martensitic transformation temperature on composition, the elastic properties of high temperature B2 phases of both NiTi and NiAI were calculated by a first-princi... To investigate the origin of the strong dependence of martensitic transformation temperature on composition, the elastic properties of high temperature B2 phases of both NiTi and NiAI were calculated by a first-principle method, the exact-muffin orbital method within coherent potential approximation. In the composition range of 50-56 at. pct Ni of NiTi and 60-70 at. pct Ni of NiAI in which martensitic transformation occurs, non-basalplane shear modulus c44 increases with increasing Ni content, while basal-plane shear modulus c' decreases. In the above composition ranges however the transformation temperature of NiAI increases with increasing Ni content while that of NiTi decreases from experimental observation. The softening of c' is experimentally observed only in NiAI, and the decrease of c' with increasing Ni content is responsible for the increase of transformation temperature. The result of the present work demonstrates that, besides c', c44 also influences the martensitic transformation of NiTi and plays quite important a role. 展开更多
关键词 NITI NiA1 Elastic constant first-principle calculation
下载PDF
Promoting wetting of Mg on the SiC surfaces by addition of Al,Zn and Zr elements:A study via first-principle calculations 被引量:1
3
作者 Weibing Guo Wenshan Bian +1 位作者 Haitao Xue Xiaoming Zhang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2022年第6期1663-1671,共9页
When preparing SiC/Mg composites,alloy elements play key roles in the nucleation and interfacial wetting.In this paper,effects of Al,Zn and Zr additions on the Mg/SiC interfacial bonding properties were investigated c... When preparing SiC/Mg composites,alloy elements play key roles in the nucleation and interfacial wetting.In this paper,effects of Al,Zn and Zr additions on the Mg/SiC interfacial bonding properties were investigated comprehensively via method of first-principle calculations.Mg(0001)/SiC(0001)interfaces with different terminations and stacking sequences were built and CⅡ-T CⅡtop interface has the largest work of adhesion(W_(ad)).Zn dopants can not improve the W_(ad)for both C-T and Si-T interfaces.Al atom can only strengthen the C-T interface.Zr addition can greatly improve the W_(ad)for both C-T and Si-T interfaces.W_(ad)of C-T interfaces can reach up to 11.55 J/m^(2) and 12.55 J/m^(2) after doping 1 monolayer(ML)of Al and Zr atoms.Larger W_(ad)can lead to lower contact angles of Mg on SiC surfaces,which can improve wetting and nucleation in SiC/Mg composites.Analysis of electronic structure shows that Al-C and Zr-C bonds have more covalent composition than the Mg-C bond,which is responsible for the improvement of interfacial bonding strength.Experimental results in references were also analyzed,which are in well agreement with our calculation results. 展开更多
关键词 Mg alloy SIC WETTING Electronic structure first-principle calculations
下载PDF
First-principle Calculation of the Properties of Ti_3SiC_2 被引量:1
4
作者 DuanwenSHI YanchunZHOU 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第2期146-148,共3页
The electronic and structural properties for Ti3SiC2 were studied using the first-principle calculation method. By using the calculated band structure and density of states, the high electrical conductivity of Ti3SiC2... The electronic and structural properties for Ti3SiC2 were studied using the first-principle calculation method. By using the calculated band structure and density of states, the high electrical conductivity of Ti3SiC2 are explained. The bonding character of Ti3SiC2 is analyzed in the map of charge density distribution. 展开更多
关键词 first-principle calculation TI3SIC2 Charge density distribution
下载PDF
First-principle calculations of interaction of O_2 with pyrite, marcasite and pyrrhotite surfaces 被引量:2
5
作者 赵翠华 陈建华 +2 位作者 李玉琼 陈晔 李伟洲 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第2期519-526,共8页
The interaction of O2 with pyrite, marcasite and pyrrhotite surfaces was studied using first-principle calculations to obtain the oxidization mechanisms of these minerals. The results show that the adsorption energy o... The interaction of O2 with pyrite, marcasite and pyrrhotite surfaces was studied using first-principle calculations to obtain the oxidization mechanisms of these minerals. The results show that the adsorption energy of O2 on pyrrhotite surface is the largest, followed by that on marcasite surface and then pyrite surface. O2 molecules adsorbed on pyrite, marcasite and pyrrhotite surfaces are all dissociated. The oxygen atoms and surface atoms of pyrite, marcasite and pyrrhotite surfaces have different bonding structures. Due to more atoms on pyrrhotite and marcasite surfaces interaction with oxygen atoms, the adsorption energies of O2 on pyrrhotite and marcasite surfaces are larger than that on pyrite surface. Larger values of Mulliken populations for O?Fe bond of pyrrhotite surface result in relative larger adsorption energy compared with that on marcasite surface. 展开更多
关键词 iron sulfide O2 adsorption surface oxidation first-principle
下载PDF
First-principle calculations of ductile CeAg intermetallic compound 被引量:1
6
作者 史耀君 杜宇雷 陈光 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第3期654-660,共7页
The first-principle calculations were performed to investigate the structural,mechanical,electronic and thermal properties of the binary ductile intermetallic compound CeAg with B2(CsCl) structure.The calculated val... The first-principle calculations were performed to investigate the structural,mechanical,electronic and thermal properties of the binary ductile intermetallic compound CeAg with B2(CsCl) structure.The calculated value of lattice constant a0 for CeAg with generalized gradient approximation is 3.713-,which is in better agreement with experimental data than local spin density approximation.The negative energy of formation implies that CeAg with B2 structure is thermodynamically stable phase.The greater separation between the d bands of Ce and Ag results in weaker bond hybridization of Ce d—Ag d,which prevents formation of directional covalent bonding.The three independent elastic constants(C11,C12 and C44) are derived and the bulk modulus,shear modulus,elastic modulus,anisotropy factor,and Poisson ratio are determined to be 57.6 GPa,15.8 GPa,43.4 GPa,3.15 and 0.374,respectively.The elastic constants meet all the mechanical stability criteria.The value of Pugh's criterion is 3.65.The ductility of CeAg is predicted if Pugh's criterion is greater than 1.75.Furthermore,the variations of volume,bulk modulus,heat capacity,and thermal expansion coefficient with temperature and/or pressure were calculated and discussed. 展开更多
关键词 CeAg first-principle elastic constant thermodynamic property
下载PDF
Energetics of He and H Atoms in W–Ta Alloys: First-Principle Calculations
7
作者 Chu-Bin Wan Su-Ye Yu Xin Ju 《Chinese Physics Letters》 SCIE CAS CSCD 2018年第4期95-97,共3页
Properties of various defects of He and H atoms in W-Ta alloys are investigated based on density functional theory. The tetrahedral interstitial site is the most configured site for self-interstitial He and H in W and... Properties of various defects of He and H atoms in W-Ta alloys are investigated based on density functional theory. The tetrahedral interstitial site is the most configured site for self-interstitial He and H in W and W-Ta alloys. Only a single He atom favors a substitutional site in the presence of a nearby vacancy. However, in the coexistence of He and H atoms in the presence of the vacancy, the single H atom favors the tetrahedral interstitial site(TIS) closest to the vacancy, and the He atom takes the vacancy center. The addition of Ta can reduce the formation energy of TIS He or H defects. The substituted Ta affects the charge density distribution in the vicinity of the He atom and decreases the valence electron density of the H atoms. A strong hybridization of the H s states and the nearest W d state s exists in W(53)He1 H1 structure. The sequence of the He p projected DOS at the Fermi energy level is in agreement with the order of the formation energy of the He-H pair in the systems. 展开更多
关键词 Ta Alloys Energetics of He and H Atoms in W first-principle calculations
下载PDF
First-principle Calculations of V/Fe Doped Anatase TiO_2 被引量:1
8
作者 CAO Hong-hong CHEN Qiang WANG Tian-min 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2006年第B12期162-166,共5页
The electronic structures of the titanium dioxide(TiO2) doped with V and Fe were analyzed by using first-principle calculations based on the density functional theory(DFT) with the full potential linearized augmen... The electronic structures of the titanium dioxide(TiO2) doped with V and Fe were analyzed by using first-principle calculations based on the density functional theory(DFT) with the full potential linearized augmented plane wave method (FP-LAPW). The fully optimized structure and the relaxation introduced by impurity were obtained by minimizing the total energy and atomic forces. The unit cell of the V-doped anatase TiO2 is smaller than that of the non-doped one, but for the Fe-doped one, the case is just the opposite. It is found that the apical Ti-O and impurity-O bond lengths of the V/Fe-doped anatase TiO2 are greater than those of the non-doped structure, but smaller for the equatorial bond length. Through the band structures and the density of states, the V-doped TiO2 is shown to be a kind of half-metal, while the Fe-doped TiO2 a kind of metal. The magnetic moments of the V/Fe-doped system are mainly generated by the dopants. The results may be helpful for us to understand the experimental outcome of this system. 展开更多
关键词 first-principle FP-LAPW DMS ANATASE electronic properties
下载PDF
First-Principle Calculations of Hardness and Melting Point of Mo_2C 被引量:1
9
作者 X.R. Wang M.F. Yan H.T. Chen 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2009年第3期419-422,共4页
This paper has constructed two kinds of atomic and electronic models for hexagonal β-Mo2C and orthorhombic α-Mo2C. The optimized lattice parameters, elastic constant matrixes and overlap population for Mo2C crystal ... This paper has constructed two kinds of atomic and electronic models for hexagonal β-Mo2C and orthorhombic α-Mo2C. The optimized lattice parameters, elastic constant matrixes and overlap population for Mo2C crystal cells have been obtained to realize the characterization of the hardness and melting point of the two structures by the first-principles plane wave pseudo potential method based on the density functional theory. The results reveal that the calculated lattice parameters of the Mo2C crystal cells agree with the experimental and other calculated data. The calculated melting point/hardness are 2715 K/11.38 GPa for β-Mo2C and 2699 K/10.57-12.67 GPa for α-Mo2C, respectively. The calculated results from the density of states (DOS) demonstrate that the hybridization effect between Mo-3d and C-2p states in α-Mo2C crystal cell is much stronger than that in β-Mo2C one. 展开更多
关键词 first-principle Mo2C HARDNESS Melting point Density of states
下载PDF
The First-Principle Calculation of La-doping Effect on Piezoelectricity in Tetragonal KNN Crystal 被引量:1
10
作者 张乔丽 朱基亮 +7 位作者 袁大庆 朱波 王明松 朱小红 范平 左翼 郑永男 朱升云 《Plasma Science and Technology》 SCIE EI CAS CSCD 2012年第5期442-444,共3页
The La-dopping effect on the piezoelectricity in the K0.5Na0.5NbO3 (KNN) crystal with a tetragonal phase is investigated for the first time using the first-principle calculation based on density functional theory. T... The La-dopping effect on the piezoelectricity in the K0.5Na0.5NbO3 (KNN) crystal with a tetragonal phase is investigated for the first time using the first-principle calculation based on density functional theory. The full potentiallinearized augumented plane wave plus local orbitals (APW-LO) method and the supercell method are used in the calculation for the KNN crystal with and without the La doping. The results show that the piezoelectricity originates from the strong hybridization between the Nb atom and the O atom, and the substitution of the K or Na atom by the La impurity atom introduces the anisotropic relaxation and enhances the piezoelectricity at first and then restrains the hybridization of the Nb-O atoms when the La doping content further increases. 展开更多
关键词 PIEZOELECTRICITY La-doping effect K0.5Na0.sNbO3 crystal first-principle cal-culation electric field gradient
下载PDF
Electronic band structures and optical properties of atomically thin AuSe: first-principle calculations
11
作者 Pengxiang Bai Shiying Guo +3 位作者 Shengli Zhang Hengze Qu Wenhan Zhou Haibo Zeng 《Journal of Semiconductors》 EI CAS CSCD 2019年第6期58-62,共5页
As a large family of 2D materials, transition metal dichalcogenides(TMDs) have stimulated numerous works owing to their attractive properties. The replacement of constituent elements could promote the discovery and fa... As a large family of 2D materials, transition metal dichalcogenides(TMDs) have stimulated numerous works owing to their attractive properties. The replacement of constituent elements could promote the discovery and fabrication of new nanofilm in this family. Using precious metals, such as platinum and palladium, to serve as transition metals combined with chalcogen is a new approach to explore novel TMDs. Also, the proportion between transition metal and chalcogen atoms is found not only to exist in conventional form of 1 : 2. Herein, we reported a comprehensive study of a new 2D precious metal selenide, namely AuSe monolayer. Based on density functional theory, our result indicated that AuSe monolayer is a semiconductor with indirect band-gap of 2.0 eV, which possesses superior dynamic stability and thermodynamic stability with cohesive energy up to–7.87 eV/atom. Moreover, it has been confirmed that ionic bonding predominates in Au–Se bonds and absorption peaks in all directions distribute in the deep ultraviolet region. In addition, both vibration modes dominating marked Raman peaks are parallel to the 2D plane. 展开更多
关键词 AuSe MONOLAYER DFT calculation 2D SEMICONDUCTOR
下载PDF
γ-and α-Ce phase diagram: First-principle calculation
12
作者 张林 李英华 +3 位作者 李雪梅 张祖根 叶想平 蔡灵仓 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第3期129-133,共5页
Controversies about the phase diagram for the isostructural y ++ a phase transition of cerium have long been standing out for several decades. To seek insight into the problems, high-precision equations of state (... Controversies about the phase diagram for the isostructural y ++ a phase transition of cerium have long been standing out for several decades. To seek insight into the problems, high-precision equations of state (EOS) for y- and a-cerium are constructed based on first-principle calculation. Versus previous works, the strong anharmonic effects of ion vibration and the variation of magnetism of y-cerium are stressed. The new EOS generally agrees well with experimental data regarding thermodynamics, phase diagrams, and phase transitions. However, new EOS predicts that another part of phase boundary in pressure-temperature space may exist except for the commonly known boundary. In addition, the well-known critical point seems to be a critical point for y-cerium to translate from a stable state to an unstable state. 展开更多
关键词 ab initio calculations phase transition equation of states
下载PDF
Transformation of long-period stacking ordered structures in Mg-Gd-Y-Zn alloys upon synergistic characterization of first-principles calculation and experiment and its effects on mechanical properties 被引量:1
13
作者 Mingyu Li Guangzong Zhang +4 位作者 Siqi Yin Changfeng Wang Ying Fu Chenyang Gu Renguo Guan 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第5期1867-1879,共13页
Based on experiments and first-principles calculations,the microstructures and mechanical properties of as-cast and solution treated Mg-10Gd-4Y-xZn-0.6Zr(x=0,1,2,wt.%)alloys are investigated.The transformation process... Based on experiments and first-principles calculations,the microstructures and mechanical properties of as-cast and solution treated Mg-10Gd-4Y-xZn-0.6Zr(x=0,1,2,wt.%)alloys are investigated.The transformation process of long-period stacking ordered(LPSO)structure during solidification and heat treatment and its effect on the mechanical properties of experimental alloys are discussed.Results reveal that the stacking faults and 18R LPSO phases appear in the as-cast Mg-10Gd-4Y-1Zn-0.6Zr and Mg-10Gd-4Y-2Zn-0.6Zr alloys,respectively.After solution treatment,the stacking faults and 18R LPSO phase transform into 14H LPSO phase.The Enthalpies of formation and reaction energy of 14H and 18R LPSO are calculated based on first-principles.Results show that the alloying ability of 18R is stronger than that of 14H.The reaction energies show that the 14H LPSO phase is more stable than the 18R LPSO.The elastic properties of the 14H and 18R LPSO phases are also evaluated by first-principles calculations,and the results are in good agreement with the experimental results.The precipitation of LPSO phase improves the tensile strength,yield strength and elongation of the alloy.After solution treatment,the Mg-10Gd-4Y-2Zn-0.6Zr alloy has the best mechanical properties,and its ultimate tensile strength and yield strength are 278.7 MPa and 196.4 MPa,respectively.The elongation of Mg-10Gd-4Y-2Zn-0.6Zr reaches 15.1,which is higher than that of Mg-10Gd-4Y0.6Zr alloy.The improving mechanism of elastic modulus by the LPSO phases and the influence on the alloy mechanical properties are also analyzed. 展开更多
关键词 Mg-Gd-Y-Zn alloys Long-period stacking ordered first-principles calculations ENTHALPIES Mechanical properties
下载PDF
Multi-electron reaction and fast Al ion diffusion of δ-MnO_(2) cathode materials in rechargeable aluminum batteries via first-principle calculations
14
作者 Lumin Zheng Ying Bai Chuan Wu 《Chinese Chemical Letters》 SCIE CAS CSCD 2024年第4期248-254,共7页
Rechargeable aluminum batteries with multi-electron reaction have a high theoretical capacity for next generation of energy storage devices. However, the diffusion mechanism and intrinsic property of Al insertion into... Rechargeable aluminum batteries with multi-electron reaction have a high theoretical capacity for next generation of energy storage devices. However, the diffusion mechanism and intrinsic property of Al insertion into MnO_(2) are not clear. Hence, based on the first-principles calculations, key influencing factors of slow Al-ions diffusion are narrow pathways, unstable Al-O bonds and Mn^(3+) type polaron have been identified by investigating four types of δ-MnO_(2)(O3, O'3, P2 and T1). Although Al insert into δ-MnO_(2) leads to a decrease in the spacing of the Mn-Mn layer, P2 type MnO_(2) keeps the long(spacious pathways)and stable(2.007–2.030 A) Al-O bonds resulting in the lower energy barrier of Al diffusion of 0.56 e V. By eliminated the influence of Mn^(3+)(low concentration of Al insertion), the energy barrier of Al migration achieves 0.19 e V in P2 type, confirming the obviously effect of Mn^(3+) polaron. On the contrary, although the T1 type MnO_(2) has the sluggish of Al-ions diffusion, the larger interlayer spacing of Mn-Mn layer,causing by H_(2)O could assist Al-ions diffusion. Furthermore, it is worth to notice that the multilayer δ-MnO_(2) achieves multi-electron reaction of 3|e|. Considering the requirement of high energy density, the average voltage of P2(1.76 V) is not an obstacle for application as cathode in RABs. These discover suggest that layered MnO_(2) should keep more P2-type structure in the synthesis of materials and increase the interlayer spacing of Mn-Mn layer for providing technical support of RABs in large-scale energy storage. 展开更多
关键词 Rechargeable aluminum batteries δ-MnO_(2) first-principles calculations Multi-electron reaction Diffusion mechanism
原文传递
First-Principles Calculation of the Topological Nodal-Line Semimetal FeGe_(2)
15
作者 Yuchen Zou Jianan Bian Yiming Yu 《材料科学与工程(中英文B版)》 2024年第1期1-6,共6页
The electronic and topological properties of FeGe2 with a tetragonal crystal structure were investigated via first-principles calculations.The results demonstrate that FeGe2 in this structure exhibits anti-ferromagnet... The electronic and topological properties of FeGe2 with a tetragonal crystal structure were investigated via first-principles calculations.The results demonstrate that FeGe2 in this structure exhibits anti-ferromagnetism,with two bands crossing the Fermi level nesting each other at high-symmetry points in the Brillouin zone,forming a nodal ring where the nodes intersect in momentum space.Additionally,it possesses nontrivial topological surface states.Upon inclusion of SOC(spin-orbit coupling),there are no significant changes observed in the band structure,nodal features,or surface states,indicating the persistence of its topological nodal-line characteristics. 展开更多
关键词 Topological semimetal first-principles calculations electronic property topological property
下载PDF
MAX phase forming mechanism of M-Al-C(M=Ti,V,Cr)coatings:In-situ X-ray diffraction and first-principle calculations 被引量:1
16
作者 Jianghuai Yuan Zhenyu Wang +5 位作者 Guanshui Ma Xiaojing Bai Yong Li Xiaoying Cheng Peiling Ke Aiying Wang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第12期140-152,共13页
The interesting hybrid properties of ceramics and metals induced by unique nano-laminated structures make the M_(n+1)AX n(MAX)phase attractive as a potential protective coating for vital structural compo-nents in hars... The interesting hybrid properties of ceramics and metals induced by unique nano-laminated structures make the M_(n+1)AX n(MAX)phase attractive as a potential protective coating for vital structural compo-nents in harsh systems.However,an extremely narrow phase-forming region makes it difficult to prepare MAX phase coatings with high purity,which is required to obtain coatings with high-temperature anti-oxidation capabilities.This work describes the dependence of the phase evolution in deposited M-Al-C(M=Ti,V,Cr)coatings as a function on temperature using in-situ X-ray diffraction analysis.Compared to V_(2)AlC and Cr_(2)AlC MAX phase coatings,the Ti_(2)AlC coating displayed a higher phase-forming tempera-ture accompanied by a lack of any intermediate phases before the appearance of the Ti_(2)AlC MAX phase.The results of the first-principle calculations correlated with the experience in which Ti_(2)AlC exhibited the largest formation energy and density of states.The effect of the phase compositions of these three MAX phase coatings on mechanical properties were also investigated using ex-situ Vickers and nano-indenter tests,demonstrating the improved mechanical properties with good stability at high temperatures.These findings provide a deeper understanding of the phase-forming mechanism of MAX phase coatings to guide the preparation of high-purity MAX phase coatings and the optimization of MAX phase coatings with expected intermediate phases such as Cr_(2)C,V_(2)C etc.,as well as their application as protective coat-ings in temperature-related harsh environments. 展开更多
关键词 MAX phase coating Phase-formation mechanism In-situ X-ray diffraction first-principle calculations Mechanical properties
原文传递
First-principles calculations of Ni–(Co)–Mn–Cu–Ti all-d-metal Heusler alloy on martensitic transformation,mechanical and magnetic properties 被引量:2
17
作者 Huaxin Qi Jing Bai +7 位作者 Miao Jin Jiaxin Xu Xin Liu Ziqi Guan Jianglong Gu Daoyong Cong Xiang Zhao Liang Zuo 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第5期930-938,共9页
The martensitic transformation,mechanical,and magnetic properties of the Ni_(2)Mn_(1.5-x)Cu_(x)Ti_(0.5) (x=0.125,0.25,0.375,0.5) and Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5)[(x=0.125,y=0.125,0.25,0.375,0.5) and (x=0.125... The martensitic transformation,mechanical,and magnetic properties of the Ni_(2)Mn_(1.5-x)Cu_(x)Ti_(0.5) (x=0.125,0.25,0.375,0.5) and Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5)[(x=0.125,y=0.125,0.25,0.375,0.5) and (x=0.125,0.25,0.375,y=0.625)]alloys were systematically studied by the first-principles calculations.For the formation energy,the martensite is smaller than the austenite,the Ni–(Co)–Mn–Cu–Ti alloys studied in this work can undergo martensitic transformation.The austenite and non-modulated (NM) martensite always present antiferromagnetic state in the Ni_(2)Mn_(1.5-x)Cu_(x)Ti_(0.5) and Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5) (y<0.625) alloys.When y=0.625 in the Ni_(2-y)Co_(y)Mn_(1.5-x)Cu_(x)Ti_(0.5) series,the austenite presents ferromagnetic state while the NM martensite shows antiferromagnetic state.Cu doping can decrease the thermal hysteresis and anisotropy of the Ni–(Co)–Mn–Ti alloy.Increasing Mn and decreasing Ti content can improve the shear resistance and normal stress resistance,but reduce the toughness in the Ni–Mn–Cu–Ti alloy.And the ductility of the Co–Cu co-doping alloy is inferior to that of the Ni–Mn–Cu–Ti and Ni–Co–Mn–Ti alloys.The electronic density of states was studied to reveal the essence of the mechanical and magnetic properties. 展开更多
关键词 Ni–Mn–Ti-based all-d-metal Heusler alloys first-principles calculations mechanical properties martensitic transformation magnetic properties
下载PDF
Initial micro-galvanic corrosion behavior between Mg_(2)Ca and α-Mg via quasi-in situ SEM approach and first-principles calculation
18
作者 Chen Xu Jianfeng Wang +4 位作者 Chen Chen Chao Wang Yufeng Sun Shijie Zhu Shaokang Guan 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第3期958-965,共8页
The initial micro-galvanic corrosion behavior of Mg-30wt%Ca alloy only containing Mg_(2)Ca andα-Mg was studied by immersion testing in a 0.9%Na Cl solution at 37°C.The quasi-in situ SEM and TEM results show that... The initial micro-galvanic corrosion behavior of Mg-30wt%Ca alloy only containing Mg_(2)Ca andα-Mg was studied by immersion testing in a 0.9%Na Cl solution at 37°C.The quasi-in situ SEM and TEM results show that Mg_(2)Ca corroded easier thanα-Mg,indicating that Mg_(2)Ca acted as an anode.The work function(Φ)for Mg_(2)Ca calculated by first-principles is significantly lower compared to that forα-Mg.The Volta potential measured by a scanning Kelvin probe force microscope reveals that the Mg_(2)Ca had a relatively low Volta potential(ψ)value.The lowerΦandψvalues for Mg_(2)Ca indicate a lower electrochemical nobility,which is consistent with the experimental phenomenon. 展开更多
关键词 Magnesium alloy Quasi-in situ SEM Galvanic corrosion first-principles calculations Work function Volta potential
下载PDF
Rational design of Fe/Co-based diatomic catalysts for Li–S batteries by first-principles calculations
19
作者 张晓雅 程莹洁 +5 位作者 赵春宇 高敬莞 阚东晓 王义展 齐舵 魏英进 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第3期402-407,共6页
Fe/Co-based diatomic catalysts decorated on an N-doped graphene substrate are investigated by first-principles calculations to improve the electrochemical properties of Li–S batteries.Our results demonstrate that Fe ... Fe/Co-based diatomic catalysts decorated on an N-doped graphene substrate are investigated by first-principles calculations to improve the electrochemical properties of Li–S batteries.Our results demonstrate that Fe CoN8@Gra not only possesses moderate adsorption energies towards Li2Snspecies,but also exhibits superior catalytic activity for both reduction and oxidation reactions of the sulfur cathode.Moreover,the metallic property of the diatomic catalysts can be well maintained after Li2Snadsorption,which could help the sulfur cathode to maintain high conductivity during the whole charge–discharge process.Given these exceptional properties,it is expected that Fe CoN8@Gra could be a promising diatomic catalyst for Li–S batteries and afford insights for further development of advanced Li–S batteries. 展开更多
关键词 Li–S battery diatomic catalyst POLYSULFIDES first-principles calculations
下载PDF
Structural,electronic,and Li-ion mobility properties of garnet-type Li_(7)La_(3)Zr_(2)O_(12) surface:An insight from first-principles calculations
20
作者 王靖轩 孙宝珍 +2 位作者 李梅 吴木生 徐波 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期652-659,共8页
Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) is a promising solid-state electrolyte for Li-ion batteries,but Li-dendrite's formation greatly limits the applications.In this paper,we systematically investigate the st... Garnet-type Li_(7)La_(3)Zr_(2)O_(12)(LLZO) is a promising solid-state electrolyte for Li-ion batteries,but Li-dendrite's formation greatly limits the applications.In this paper,we systematically investigate the stability,electronic properties,and Li-ion mobility of the LLZO surface by the ifrst-principles calculations.We consider the(110) and(001) slab structures with different terminations in the t-and c-LLZO.Our results indicate that both(110) and(001) surfaces prefer to form Li-rich termination due to their low surface energies for either t-or c-LLZO.Moreover,with the decrease of Li contents the stability of Li-rich surfaces is improved initially and degrades later.Unfortunately,the localized surface states at the Fermi level can induce the formation of metallic Li on the Li-rich surfaces.In comparison,Li/La-termination has a relatively low metallic Li formation tendency due to its rather low diffusion barrier.In fact,Li-ion can spontaneously migrate along path II(Li3→Li2) on the Li/La-T(001) surface.In contrast,it is more difficult for Li-ion diffusion on the Li-T(001) surface,which has a minimum diffusion barrier of 0.50 eV.Interestingly,the minimum diffusion barrier decreases to 0.34 eV when removing four Li-ions from the Li-T(001) surface.Thus,our study suggests that by varying Li contents,the stability and Li-ion diffusion barrier of LLZO surfaces can be altered favorably.These advantages can inhibit the formation of metallic Li on the LLZO surfaces. 展开更多
关键词 solid-state electrolyte Li_(7)La_(3)Zr_(2)O_(12)(LLZO)surface Li-ion migration first-principles calculations
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部