HONG Youshi Institute of Mechanics
,
Academia Sinica
,
Beijing
,
ChinaW.R.TYSON B.FAUCHER Physical Metallurgy Research Laboratories
,
CANMET
,
Ottawa
,
Canada HONG Youshi Institute of Me-chanics
,
Academia Sinica
,
Beijing 100080 China
金属学报(英文版)
The inclusion parameters,fracture surface morphology and void growth characteristics of ten- sile and fracture toughness specimens of 2.25Cr-1Mo steels with and without rare-earth (RE)additions have been investigated by quantitative metaltography(QTM),scanning elec- tron microscopy(SEM)and energy dispersive spectroscopy(EDS).There is a substantially higher density of inclusions in the RE-treated steel,which has lower values of fracture proper- ties including critical values of COD and J integral(δ_c and J_(IC)),fracture strain(ε_f) and Charpy V-notch energy(CVN).The fracture surface of the RE-treated steel comprises equiaxed dimples of diameters comparable with its inclusion spacing,whereas for the non-RE-treated steels,a wide range of dimple sizes is found with average diameter much smaller than the corresponding inclusion spacing.The investigation indicates that the lower values of fracture properties for the steel with RE at room temperature may be ascribed to its large content of RE-containing inclusions.
关键词:
Cr-Mo steel
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null
,
null
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null
WADSWORTH Jeffrey and FLUSS Michael(Chemistry and Materials Science Directorate
,
Lawrence Livermore National Laboratory
,
Livermore
,
CA 94551)
金属学报(英文版)
The role of the National Laboratories is summarized from the era of post World War II to the present time. The U.S. federal government policy for the National Laboratories and its influence on their materials science infrastructure is reviewed with respect to .determining overall research strategies, various initiatives to interact with industry (especially in recent years),building facilities that serve the nation, and developing leading edge research in the materials sciences. Despite reductions in support for research in the U.S. in recent years, and uncertainties regarding the specific policies for Research &Development (R&D) in the U.S., there are strong roles for materials research at the National Laboratories. These roles will be centered on the abilities of the National Laboratories to field multidisciplinary teams, the use of unique cutting edge facilities, a focus on areas of strength within each of the labs,increased teaming and partnerships, and the selection of motivated research areas. It is hoped that such teaming opportunities will include new alliances with China, in a manner similar, perhaps, to those recently achieved between the U.S. and other countries.
关键词:
: U.S. Materials Science. U.S. National Laboratories and Facilities
,
null
Communications in Theoretical Physics
The unified theoretical calculation of thermal shifts (TS) of R-1 and R-2 lines and thermal broadenings (TB) of R, R' and B lines for ruby was carried out for the first time. The calculated results are in very good agreement with a great number of experimental data. Especially by using quantum theory and taking into account all the admixtures of wavefunctions within d(3) electronic configuration, all the Gamma M in electron-phonon interaction (EPI), the electronic energy spectrum and lattice-vibration Spectrum, the very important contributions to TS and TB from single-phonon direct process were theoretically calculated in detail. The microscopic essentials of various contributions are revealed, and the mistakes in previous work are remedied.
关键词:
diamond anvil cell;pressure measurement;spectroscopy;temperatures
Communications in Theoretical Physics
On the basis of the unified calculation of the thermal shifts of R-1 line, R-2 line and ground-state-splitting as well as the thermal broadenings of R, R' and B line-groups for ruby, by taking into account all the levels and admixtures of wavefunctions within d(3) electronic configuration and all the GammaM in electron-phonon interaction, the transition probabilities of direct and Raman processes have theoretically been calculated. The thermal broadenings, of R, R' and B line-groups have successfully been interpreted in terms of the direct and Raman processes of acoustic phonons. The theoretically predicted transition probabilities are in good agreement with the experimental ones.
关键词:
crystal fields;electron-phonon interaction;thermal broadening;transition probability;direct and Raman processes;shifts
LI Guirong
,
WANG Hongming
,
DAI Qixun
,
ZHAO Yutao
,
LI Jingsheng
钢铁研究学报(英文版)
The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3containing mould fluxes were studied. The corresponding physical properties of 3791%CaO4309%SiO25%Al2O35%MgO2%Li2O7%B2O3 mould fluxes were as follows: the melting point was 909 ℃, the flowing temperature was 1 160 ℃, the viscosity and surface tension at 1 300 ℃ were 04 Pa·s and 032 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.
关键词:
B2O3containing mould flux;fluoridefree flux;harmless flux;physical property
Journal of Applied Physics
The magnetic properties of R2Co14B1-xCx (x=0, 0.5 and R=Y, Sm) compounds have been studied by measuring the temperature dependence of the easy- and hard-magnetization curves on magnetically aligned samples between 1.5 and 300 K for Y2Co14(B,C) and at 4.2 K for Sm2Co14(B,C). The magnetic anisotropy of Y2Co14B increases due to the substitution of C for B, whereas the saturation magnetization decreases. Between 1.5 and 300 K, the anisotropy field of Y2Co14B0.5C0.5 increases about 2 T and the Co moment decreases about 0.05mu(B). The anisotropy field Of Sm2Co14B also increases upon C substitution and the saturation magnetization decreases slightly. The ac susceptibilities of both SM2Co14B and Sm2Co14B0.5C0.5 exhibit anomalies that may arise from a spin reorientation within the basal plane.
关键词:
nd2fe14b;exchange;nd2co14b;r2fe14b;field
Journal of Alloys and Compounds
High field magnetization curves have been measured at 4.2 K on magnetically aligned R2Co14B1-xCx (R = Pr, Nd; x = 0.0, 0.2 and 0.5) samples with the magnetic field applied parallel and perpendicular to the alignment direction. It is found that, for both the praseodymium and the neodymium compounds, the saturation magnetization decreases on substitution of carbon for boron. In the Nd2Co14B1-xCx system, the critical field of the first-order magnetization process (FOMP) increases with increasing carbon content. No FOMP is observed in the Pr2Co14B1-xCx system. The temperature dependence of the a.c. susceptibility shows that in Nd2Co14B1-xCx the spin reorientation temperature decreases with increasing carbon content. A spin reorientation phenomenon is also observed in Pr2Co14B0.8C0.2 and in Pr2Co14B0.5C0.5. Also in these compounds, the spin reorientation temperature decreases with increasing carbon content.
关键词:
nd2fe14b;exchange;r2fe14b;field
Communications in Theoretical Physics
By means of improved ligand-field theory, the "pure electronic" presure-induced shifts (PSs) and the PSs due to electron-phonon interaction (EPI) of the R-1, R-2, B-1, B-2, B-3, and R-3' lines and the ground-state zero-lield-splitting' of ruby have been uniformly calculated. The calculation results are in very good agreement with all the experimental data. At normal pressure, ruby is a crystal with very strong crystal field. Thus the admixture of vertical bar t(2)(2)(T-3(1))e(4)T(2)> and vertical bar t(2)(32)E > bases in the wavefunction of R-1 level of ruby is small at normal pressure, and it gradually decreases with increasing pressure, which causes the R-1-line PS of ruby to monotonously red shift with approximate linearity. The combined effect of the pure electronic PS of R, line and the PS of R, line due to EPI gives rise to the total PS of R, line. The analyses and comparisons among the features of R-1-line PSs of three laser crystals (ruby, GSGG:Cr3+ and GGG:Cr3+) have been made, and the origin of their difference has been revealed.
关键词:
high-pressure effect;electron-phonon interaction;R;R ';and B;line-groups;ground-state zero-field-splitting;admixture of;[t(2)(2)(T-3(1))e(4)T(2)) and [t(2)(3)(2) E);laser crystal;calibration;spectra
