T.Gang
,
J.Zhang
,
M.B.Zhang and F.X.Liu (1)AWPT National Key.
,
HIT
,
Harbin 15001
,
China 2)State 159 Factory
,
China)
金属学报(英文版)
A primary study on Processing in X - ray inspection of spot weld for aluminum alloy spot welding,in- cluding for background simulation,acquisition of ideal binary image, and extraction and identifi- cation of defect features was presented.
关键词:
X - ray detection
,
null
,
null
,
null
Shiqiang LU
,
Baozhong SHANG
,
Zijian LUO
,
Fangchang ZENG
材料科学技术（英文）
The constitutive relationship for MP159 alloy, a kind of high strength cobalt-base superalloy, was studied based on the experimental results of compression tests carried out in the THERMECMASTER--Z hot work simulating test machine. The constitutive relationship model using Zener-Hollomon parameter as primary variable is proposed, and the constitutive equation for MP159 alloy is firstly formulized. This equation well represents the relationship of flow stress with thermomechanical parameters, i.e. strain, strain rate and temperature, in a large deformation (a true strain of 1.10) and a wide range of deformation temperatures and strain rates. It can be used for the finite element simulation of plastic forming process and the dissipative structure theory and dynamic material modeling.
关键词:
Guangwei HAN
,
Di FENG
,
Ming YIN
,
Wujun YE and Heli LUO(Dept. of Superalloys
,
Central Iron and Steel Research Institute
,
Beijing 100081
,
China)
材料科学技术（英文）
The recrystallization behaviour of cold drawn MP159 alloy was investigated by optical and TEM examinations. It is found that the platelet ε phase in the MP alloy inhibits the recrystallization,and this effect makes the MP159 alloy with high recrystallization temperature of about 920℃.This inhibition mainly comes from the increasing of the interfacial energy, which results from the change of the coherent interfaces of (0001)hcp//(111)fcc into the incoherent interfaces when the recrystallizing grain fronts bypass the platelet ε martensite. The increasing of the interfacial energy also causes the dissolution of a few segments on the ε martensite platelets, which decreases the strength of the MP alloy
关键词:
Guangwei HAN
,
Di FENG
,
Ming YIN and Nanseng YANG(Central Iron and Steel Research Institute
,
Beijing 100081
,
China)(To whom correspondence should be addressed)
材料科学技术（英文）
By comparing the relationship of room temperature yield strength with the reduction of cold rolled MP159 alloy before and after aging at 650℃, and by means of TEM examination on the corresponding microstructures, the occurrence of fcc(α)→hcp(ε) martensitic transition in MP159 alloy during cold deformation and the variation of the platelet E phase during aging have been Studied. The results show that the platelet E phase is really formed when the cold deformation reaches a critical value, and both the amount and the width of the platelet B phase would further increase during 650℃ aging. The increases of the amount and the width of the platelet εphase result in an additional increase of yield strength. Therefore, it is concluded that the additional hardening effect of MP159 alloy after aging is not only from the precipitation of Ni3X disperse phase but also from the volume fraction increase of the platelet ε phase. Further occurrence of the martensitic transition during aging may be due to the elimination of residual compression stress within matrix induced by the fcc(α)→hcp(ε) transition during cold deformation
关键词:
Journal of Physics-Condensed Matter
The electronic structure of TiB2 has been calculated using the self-consistent LMTO-ASA method. Our results have been compared with experimental and other theoretical work. We find that the pseudo-gap at the Fermi level is the competing effect of Ti 3d resonance and strong hybridization between Ti 3d and B 2p states. The bonding nature of TiB2 is discussed. We have carried out calculations of the equation of state (EOS) Of TiB2; it is found that our first-principles calculated results support the universal model of EOS proposed by Vinet et al. The room-temperature isotherm is also plotted.
关键词:
binding-energy relation;borides;solids;chemisorption;metals
SUN Wenqiang
,
CAI Jiuju
,
MAO Hujun
,
GUAN Duojiao
钢铁研究学报(英文版)
As the largest energy consuming manufacturing sector and one of the most important sources of carbon dioxide (CO2) emissions, the China′s iron and steel industry has paid attention to the study of changing trend and influencing factors of CO2 emissions from energy use. The logarithmic mean Divisia index (LMDI) technique is used to decompose total change in CO2 emissions into four factors: emission factor effect, energy structure effect, energy consumption effect, and steel production effect. The results show that the steel production effect is the major factor which is responsible for the rise in CO2 emissions; whereas the energy consumption effect contributes most to the reduction in CO2 emissions. And the emission factor effect makes a weak negative contribution to the increase of CO2 emissions. To find out the detailed relationship between change in energy consumption or steel production and change in CO2 emissions, the correlation equations are also proposed.
关键词:
CO2 emissions
,
energy use
,
LMDI technique
,
steel production
,
energy consumption
American Mineralogist
A natural high-pressure phase of titanium oxide with alpha-PbO2-structure has been found in omphacite from coesite-bearing eclogite at Shima in the Dabie Mountains, China. High-resolution transmission electron microscope observations have revealed an orthorhombic lattice, corresponding to alpha-PbO2-type TiO2, with cell parameters a = 0.461 nm, b = 0.540 nm, c = 0.497 nm and space group Pbcn. It occurs as nanometer-thick (< 2 nm) lamellae between multiple twinned rutile crystals, providing additional evidence of very high-pressure, metamorphism at 7 GPa, 900 degrees C. This implies subduction of continental material to a depth of more than 200 kilometers. alpha-PbO-type TiO2 could be an extremely useful index mineral for ultrahigh-pressure.
关键词:
high-pressure phase;ries crater;rutile;polymorph;titanium
Journal of Physics and Chemistry of Solids
The ground state splitting of d(5) configuration ion Mn2+ in ZnS:Mn2+ has been studied by diagonalizing the energy matrices for electron-electron repulsion, spin-orbit coupling and trigonal ligand field interactions. It is shown that in order to give a unified explanation for the EPR parameters a, D and (a - F) for Mn2+ in ZnS:Mn2+, a positive Dq has to be employed. This means that in tetrahedral ZnS the sulfur ion has a positive effective charge. This unusual result supports the Pauling's speculation that the sulfur ion in ZnS may be looked upon as an electron donor that forms a quadricovalent argon state of S2+ with sp(3) hybrid configuration. (C) 2003 Elsevier Ltd. All rights reserved.
关键词:
electron paramagnetic resonance;site symmetry;ion;zns;spectra;sulfide
Journal of Magnetism and Magnetic Materials
The ground-state magnetic properties of the spin-2 transverse Ising model with a longitudinal crystal field are studied within the framework of mean-field theory (MFT) and effective-field theory (EFT), respectively. The phase diagrams and magnetization curves are examined in detail. It is found that the system exhibits a tricritical behavior in the ground-state phase diagrams. Some interesting phenomena have been found, especially the first-order phase transition from one ordered phase to the other ordered phase, which is due to the high spin. The spin correlation has important effect on the magnetic properties of the system. We also find that the ground-state phase diagrams of the spin-2 transverse Ising model are very different from those of the spin-3/2 transverse Ising model. (C) 2007 Elsevier B.V. All rights reserved.
关键词:
spin-2 transverse ising model;mean-field theory;effective-field;theory;first-order phase transition;crystal-field;phase
