Y.Kurata and H.Utsumi (Japan Atomic Energy Research Institute
,
Tokai-mura
,
Naka-gun
,
Ibaraki-ken
,
319-1195
,
Japan)(Tohoku University
,
Sendai
,
980-8579
,
Japan)
金属学报(英文版)
Applicability of the following creep constitutive equations was investigated for normal type creep curves of Ni-18.5Cr alloy and tertiary creep dominant curves of Ni-18.5Cr16W alloy under constant load: the θ projection method describing a creep curse by a sum of two exponential terms, modified θ method describing a primary creep stage by an exponential term and a tertiary creep stage by a logarithmic term, modified Ω method describing a creep curve by a sum of two logarithmic term, 2θ method with only a tertiary creep component and Ω method. The θ, modified θ and modified Ω methods can describe normal type and tertiary creep dominant curves. Tertiary creep dominant curves of Ni-18.5Cr-16W alloy at 900℃ are also described using 2θ and Ω methods. Applicability of the modified θ and modified Ω methods is superior for constant load creep curves because they can predict creep curves up to rupture and rupture life accurately and conservatively.
关键词:
creep equation
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null
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null
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null
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null
材料科学技术（英文）
The results of molecular dynamics calculations on the interfacial energies and atomic structures of Ag/Ni and Cu/Ni interfaces are presented. Calculation on Ag/Ni interfaces with low-index planes shows that those containing the (111) plane have the lowest energies, which is in agreement with the experiments. Comparing surface energy with interfacial energy, it is found the order of the interfacial energies of Ag/Ni and Cu/Ni containing the planes fall in the same order as solid-vapor surface energies of Ag, Cu and Ni. In this MD simulation, the relaxed atomic structure and dislocation network of (110)(Ag)parallel to(110)(Ni) interface are coincident to HREM observations.
关键词:
molecular dynamics;interfacial energy;atomic structure;heterophase;boundary;fcc metals;model;boundaries;liquid;nickel
Haijiang LIU
,
Shaoqing WANG
,
An DU
,
Caibei ZHANG
材料科学技术（英文）
The results of molecular dynamics calculations on the interfacial energies and atomic structures of Ag/Ni and Cu/Ni interfaces are presented. Calculation on Ag/Ni interfaces with low-index planes shows that those containing the (111) plane have the lowest energies, which is in agreement with the experiments. Comparing surface energy with interfacial energy, it is found the order of the interfacial energies of Ag/Ni and Cu/Ni containing the planes fall in the same order as solid-vapor surface energies of Ag, Cu and Ni. In this MD simulation, the relaxed atomic structure and dislocation network of (110) Ag||(110) Ni interface are coincident to HREM observations.
关键词:
Molecular dynamics
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null
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null
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null
K. Mii (Sumitomo Metal Industries
,
Ltd.
,
1-t-3 Otemachi
,
Tokyo 100
,
Japan)M Amano (National Research Institute for Metals
,
1-2-1 Sengen
,
Tsukuba 305
,
Japan)
金属学报(英文版)
The R & D of hydrogen absorbing alloys in Japan started in the early 1970s.Many alloys such as TiMm1.5 based alloys, Fe-Ti-O alloys (e.g. FeTi1.15 O0.024) andthe(mischmetal)Ni5 based alloys (e.g. MmNi4.5 Cr0.46 Mn0.04) were developed by the early 1980s. The application of these alloys to hydrogen storage, heat storage, heat pump, hydrogen purification and motor vehicles has been tried in many iaboratories,and the various techniques for using hydrogen absorbing alloys have been developed.The standarkization of evaluation methods for hydrogen absorbing alloys has been promoted by the Ministry of International Trade and Industry (MITI), and four of them were established as Japanese Industrial Standard (JIS).Alloys for Ni-Metal Hydride batteries have been extensively investigated since 1987in Japun. Mm-Ni-Co-Al-Mn alloys (e.g. MmNi3.55 Co0.75Al0.9Mn0.4) have been devel-oped and commereialized since 1990. The amount of production of small-size Ni-MH batteries in 1995 was about three hundred milliion in number and about one hundred billion yen. The R & D for higher enerpy-density Ni-MH batteries is intensively in progress.MITI and STA (Science and Technology Agency) have promoted the R & D of hydro-gen absorbing alloys in Japan by carrying out the national projects such as Sunshine Program (MITI: 1974-1993) and Utilization of Wind Engeray (STA 1980-1985). The New Sunshine Program (MITI 1993-2020) have started in 1993. This program con-tains the application of hydrogen absorbing alloys to Economical- Enerpy- City System and to We-NET (International Clean Energy System of Technology Utilizing Hydro-gen: World Energy Network.
关键词:
hydrogen absorbing alloy
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null
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null
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null
Semiconductor Science and Technology
From the high-order perturbation formulae based on the two spin-orbit coupling parameter model, the electron paramagnetic resonance (EPR) parameters D, Deltag(//) (= g(//) - g(s)) and Deltag(perpendicular to) (= g(perpendicular to) - g(s)) for four Co2+ centres in Co2+-doped cubic (3C), hexagonal (2H) and 4H polytype ZnS crystals are studied using the parameters related to the structural data and the optical spectra of the studied systems. From the studies, the defect structures (characterized by the atomic positions, i.e. the relative atomic displacements delta(i) and epsilon(i) of Co2+ and S2- from the ideal positions) for Co2+ in 2H- and 4H-ZnS are obtained (for 3C-ZnS, Co2+ in the regular cubic position). The EPR parameters of various Co2+ centres in 3C-, 2H- and 4H-ZnS are also reasonably explained.
关键词:
superposition model;polymorphic zns;crystal;semiconductors;spectra;site
B.W. Wang
,
H. Shen
金属学报(英文版)
Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.
关键词:
solar selective thin film
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null
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null
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null
XU Xiuguang WANG Changzhen TU Ganfeng Northeast University of Technology
,
Shenyang
,
China.
材料科学技术（英文）
Thermodynamic properties of 3Y_2O_3·5Al_2O_3 double compound have been determined with CaF_2 single crystal electrolyte galvanic cell at 1049 K to 1230 K.The galvanic cell used can be expressed as: Pt,O_2(g)丨Y_2O_3(s),YOF_((s))丨CaF_2丨YOF_((s)), 3Y_2O_3·5Al_2O_(3(s))丨Al_2O_(3(s))丨O_2(g),Pt, of which the cell reaction is; 3Y_2O_(3(s))+SAl_2O_(3(s))=3Y_2O_3·SAl_2O_(3(s)) The following result is obtained: A_fG°(3Y_2O_3·5Al_2O_3)=-939500+765.90T±710J/mol where,△fG°(3Y_2O_3·5Al_2O_3)is the free energy of formation of 3Y_2O_3·5Al_2O_3 from Y_2O_3 and Al_2O_3.
关键词:
rare earth
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null
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null
