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Structural, mechanical, electronic properties, and debye temperature of quaternary carbide Ti3NiAl2C ceramics under high pressure: A first-principles study

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Chinese Physics B 2021年第3期30卷 416-422页

作者： Diyou Jiang Wenbo Xiao Sanqiu Liu Key Laboratory of Nondestructive Testing Ministry of EducationNanchang Hangkong UniversityNanchang 330063China Fujian Science&Technology Innovation Laboratory for Energy Devices of China(21C-LAB) Ningde 352100China Department of Physics Nanchang UniversityNanchang 330047China

Quaternary carbide Ti3NiAl2C ceramics has been investigated as a potential nuclear fusion structural material,and it has advantages in certain aspects compared with Ti2AlC,Ti3AlC2,and Ti3SiC2 structural *** this paper,quaternary carbide Ti3NiAl2C ceramics is pressurized to investigate its structural,mechanical,electronic properties,and debye *** carbide Ti3NiAl2C ceramics still maintains a cubic structure under pressure(0–110 GPa).At zero pressure,quaternary carbide Ti3NiAl2C ceramics only has three bonds:Ti–Al,Ni–Al,and Ti–***,at pressures of 20 GPa,30 GPa,40 GPa,60 GPa,and 70 GPa,new Ti–Ni,Ti–Ti,Al–Al,Ti–Al,and Ti–Ti bonds *** the pressure reaches 20 GPa,the covalent bonds change to metallic *** volume of quaternary carbide Ti3NiAl2C ceramics can be compressed to 72%of its original volume at *** can improve the mechanical strength and ductility of quaternary carbide Ti3NiAl2C *** 50–60 GPa,its mechanical strength can be comparable to pure tungsten,and the material changes from brittleness to ***,the degree of anisotropy of quaternary carbide Ti3NiAl2C ceramics increases with the increasing *** addition,we also investigated the debye temperature,density,melting point,hardness,and wear resistance of quaternary carbide Ti3NiAl2C ceramics under pressure.

关键词： quaternary carbide Ti3NiAl2C ceramics structural properties mechanical properties electronic properties debye temperature first-principles

EFFECT OF HYDROGEN ON debye temperature AND LATTICE PARAMETER OF Ti-30Mo ALLOY

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Acta Metallurgica Sinica(English Letters) 1991年第3期4卷 177-181页

作者： YU Bingxi GAO Shujun Institute of Metal Research,Academia Sinica,Shenyang,China

The variations of debye temperature and lattice parameter of Ti-30Mo alloy with different hydrogen contents were measured by means of X-ray *** was found that as the hydrogen content increases,the debye temperature decreases,but the lattice parameter of the aUoy *** above results experimentally support the decohesion theory that the in- crease of hydrogen in metals will weaken the cohesive force between the atoms and make met- als brittle.

关键词： debye temperature lattice parameter lattice decohesion theory Ti alloy

debye temperature AND VALENCE ELECTRON STRUCTURE IN INTERMETALLIC TiAl

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Transactions of Nonferrous Metals Society of China 1992年第2期2卷 47-50页

作者： Wang Yandong Sun Zuqing Chen Guoliang He Changzhi Beijing Universiy of Science and Technology Beijing 10083China Central Iron and Steel Research Institute Beijing 100083China

The debye temperature 0D of intermetallic compound TiAl at room temperature was determined by means of X-ray *** experiments show that the debye temperature of TiAl is 515 K,which is obviously higher than that of Al(394 K)or Ti(380 K).The experimental results indicate that the bonding in the intermetallic compound TiAl is stronger than that in pure metal Ti or Al which is in good agravement with the calculation of its valence electron *** relationship between the debye temperature of TiAl and its brittle-ductile transition temperature is also dealt with in the paper.

关键词： debye temperature intermetallic TiAl X-ray diffraction

Calculation of Half-Metal, debye and Curie temperatures of Co_2 VAl Compound: First Principles Study

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Communications in Theoretical Physics 2015年第5期63卷 641-647页

作者： Arash Boochani Heidar Khosravi Jabbar Khodadadi Shahram Solaymani Masoud Majidiyan Sarmazdeh Rohollah Taghavi Mendi Sayed Mohammad Elahi Department of Physics Kermanshah Branch Islamic Azad University Young Researchers and Elite club Kermanshah Branch Islamic Azad University Department of Physics Payame Noor University Department of Physics Mashhad Branch Islamic Azad University

By FP-LAPW calculations, the structural, elastic, debye and Curie temperatures, electronic and magnetic properties of Co2 VAl are investigated. The results indicate that Ferromagnetic （FM） phase is more stable than Anti- Ferromagnetic （AFM） and Non-magnetic （NM） ones. In addition, C11-C12 〉 0, C44 〉 0, and B 〉 0 so Co2 VAl is an elastically stable material with high debye temperature. Also, the BIG ratio exhibits a ductility behavior. The relatively high Curie temperature provides it as a favorable material for spintronic application. It＇s electronic and magnetic properties are studied by GGA ＋U approach leading to a 100% spin polarization at Fermi level.

关键词： exchange energy debye temperature Curie temperature Co2VAl GGA+U

First-principles calculations of elasticity and thermodynamic properties of LaNi_5 crystal under pressure

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Chinese Physics B 2009年第2期18卷 738-743页

作者：陈东陈敬东赵丽华王春雷余本海施德恒 College of Physics and Electronic Engineering Xinyang Normal University College of Physics and Information Engineering Henan Normal University

This paper investigates the equilibrium lattice parameters, heat capacity, thermal expansion coefficient, bulk modulus and its pressure derivative of LaNi5 crystal by using the first-principles plane-wave pseudopotential method in the GGA-PBE generalized gradient approximation as well as the quasi-harmonic debye model. The dependences of bulk modulus on temperature and on pressure are investigated. For the first time it analyses the relationships between bulk modulus B and temperature T up to 1000 K, the relationship between bulk modulus B and pressure at different temperatures are worked out. The pressure dependences of heat capacity Cv and thermal expansion α at various temperatures are also analysed. Finally, the debye temperatures of LaNi5 at different pressures are successfully obtained. The calculated results are in excellent agreement with the experimental data.

关键词： hydrogen storage debye temperature thermodynamic properties LaNi5

Properties of Fe-Mn-Al alloys with different Mn contents using density functional theory

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Rare Metals 2023年第4期42卷 1387-1397页

作者： Xiang Luo Jing Feng Ya-Hui Liu Ming-Yu Hu Xiao-Yu Chong Ye-Hua Jiang Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming650093China

The chemical stability,electronic structures,mechanical properties and debye temperature of Fe-MnAl alloys were investigated using first-principles *** formation enthalpy and cohesive energy are negative for Fe-Mn-Al alloys,showing that they are thermodynamically *** has the lowest formation enthalpy,indicating that FeAl is the most stable alloy in the Fe-Mn-Al *** partial density of states,total density of states and electron density distribution maps were used to analyze the physical properties of the Fe-MnAl alloys.A combination of mainly covalent and metallic bonds exists in these Fe-Mn-Al alloys,resulting in good electronic conductivity,high melting points,and high *** alloys display disparate anisotropy due to the calculated different shapes of the 3D curved surface of the Young's modulus and anisotropic *** has the highest bulk modulus,shear modulus and Yong's modulus of 187.1,119.8 and 296.2 GPa,***,the debye temperatures and sound velocity of these Fe-Mn-Al compounds were explored.

关键词： Fe-Mn-Al alloys Electronic structures Stability Mechanical properties debye temperature First-principles calculation

Mechanical properties,thermophysical properties and electronic structure of Yb^(3+)or Ce^(4+)-doped La_(2)Zr_(2)O_(7)-based TBCs

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Journal of Rare Earths 2023年第4期41卷 588-598页

作者： Pengsen Zhao Haizhong Zheng Guifa Li Yongxiang Geng Yixin Xiao Hongbo Guo Ping Peng School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Material Science and Engineering Nanchang Hangkong UniversityNanchang 330063China School of Material Science and Engineering Hunan UniversityChangsha 410082China

First-principles calculations based on density functional theory were perfo rmed to investigate the cohesive energies,elastic modulus,debye temperatures,thermal conductivities and density of states of La_(2-x)Yb_(x)Zr_(2)O_(7),La_(2)Zr_(2-x)Ce_(x)O_(7)and La_(2-x)Yb_(x)Zr_(2-x)Ce_(x)O_(7)(x=0.00,0.25,0.50,0.75,1.00)*** results show that doping Yb~(3+)or Ce~(4+)into La_(2)Zr_(2)O_(7)reduces its elastic modulus,thermal conductivity and debye *** with La_(2-x)Yb_(x)Zr_(2)O_(7)(x≠0.00),La_(2)Zr_(2-x)Ce_(x)O_(7)compounds have better ductility and lower debye te *** debye temperature values of La_(2)Zr_(2-x)Ce_(x)O_(7)(x≠0.00)co mpounds are in the range of 485.0-511.5 *** all components,the fluorite-type La_(2-x)Yb_(x)Zr_(2-x)Ce_(x)O_(7)(x=0.75,1.00)compounds exhibit better mechanical and thermophysical properties,and their thermal conductivity values are only 1.213-1.246 W/(m·K)(1073 K),which are 14.5%-16.7%lower than that of the pure La_(2)Zr_(2)O_(7).Thus,our findings open an entirely new avenue for TBCs.

关键词： First-principles calculations La_(2)Zr_(2)O_(7) Thermal conductivity debye temperature Rare earths

Thermomechanical Analysis of (Cu_(0.5)Tl_(0.5))-1223 Substituted by Pr and La

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Journal of Materials Science & Technology 2012年第2期28卷 169-176页

作者： A.I.Abou Aly R.Awad I.H.Ibrahim M.Kamal M.Anas Physics Department Faculty of ScienceAlexandria University Physics Department Faculty of ScienceMansoura University

The thermomechanical analysis （TMA） of Cu0.5T10.5Ba2Ca2-xRxCu30110-δ, where R=Pr and La, with 0.0〈x〈0.15, was carried out in temperature range from 450 to 1145 K. The samples were prepared by singlestep solid state reaction technique. The prepared samples were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The superconductivity of the prepared samples was investigated by electrical resistivity measurement. The results showed that low substitution content enhanced the （Cu0.5Tlo.5）- 1223 phase formation, while the higher substitution content degraded this phase. The higher superconducting transition temperatures Tc were found to be 114 K and 109 K at x= 0.025 for Pr- and La-substitutions, respectively. The average linear thermal expansion coefficient increased as x increased, while the shrinkage temperature decreased as x increased. Those results were emphasized by porosity and Vickers microhardness calculations. debye temperature 0D was calculated from the linear thermal expansion coefficient data and correlated to Tc to estimate the electron-phonon coupling λep.

关键词： (Cu0.5Tl0.5)-1223 Thermomechanical analysis Thermal expansion coefficient debye temperature

Theoretical study of the elastic properties of titanium nitride

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Acta Metallurgica Sinica(English Letters) 2009年第2期22卷 146-152页

作者： Dong CHEN Jingdong CHEN Yinglu ZHAO Benhai YU Chunlei WANG Deheng SHI College of Physics and Electronic Engineering Xinyang Normal University Xinyang 464000 China College of Physics and Electronic Engineering Ludong University Yantai 264025 China

The equilibrium lattice parameter, relative volume V/V0, elastic constants Cij, and bulk modulus of titanium nitride are successfully obtained using the ab initio planewave pseudopotential （PW-PP） method within the framework of density functional theory. The quasi-harmonic debye model, using a set of total energy vs molar volume obtained with the PW-PP method, is applied to the study of the elastic properties and vibrational effects. We analyze the relationship between the bulk modulus and temperature up to 2000 K and obtain the relationship between bulk modulus B and pressure at different temperatures. It is found that the bulk modulus B increases monotonously with increasing pressure and decreases with increasing temperature. Moreover, the debye temperature is determined from the non-equilibrium Gibbs functions.

关键词： Elastic constants debye temperature Ab initio calculations Titanium nitride