NING Yuantao
,
S. H. Whang Institute of Precious Metals
,
Kunming
,
Yunnan
,
China. Barnett Institute of Northeastern University
,
Boston
,
MA 02115
,
U. S. A.
材料科学技术（英文）
Various Mo-base alloys with high melting temperature were processed into ribbons and foils by the arc melt-spinning and the arc melt hammer-anvil technique. The preparation of ribbon and foil was introduced. The mechanical proper- ties, the surface topology and the microstructure of rapidly solidified Mo-base alloys containing B were examined. A strong grain refinement and a strong age-hardening response were observed on the as-quenched and the age specimens, the precipitates which cause age hardening were identified to be Mo_2B in Mo-B alloys, Mo_2B and ZrB_2 in Mo-Zr-B alloys, and Mo_2B and ThB_4 in Mo-Th-B alloys. The results indicate that the high strength Mo-base alloys containing boride precipitates can be developed by rapid solidifica- tion technique.
关键词:
Mo-alloys
,
null
,
null
,
null
,
null
郭志军
,
周建军
,
钟彦平
,
张玉福
,
吴学纲
材料保护
NK-HITEN610U2钢板已在我国用于液态烃球罐,由于液体烃中常含有水分和硫化氢,该材料在湿硫化氢环境中的耐蚀特性尚不明确.对采用回火焊道的焊接接头,经恒负荷拉伸、恒应变、焊接约束试板、氢诱导开裂、断裂韧性等试验和断口分析,对该钢板及其焊接接头在湿硫化氢环境中的抗H2S应力腐蚀开裂(SSC)性能进行了系统研究.发现其因母材中存在夹杂物偏析而对氢诱导裂纹(HIC)敏感,未经热处理的焊接接头,临界开裂应力指数Sc值小于10,材料在H2S介质中的临界应力强度因子KISCC值38 MPa·m-1/2,对SSC有一定的敏感性,认为用该材料在湿硫化氢环境中存在发生SSC的危险.据此,提出了球罐的检验和监控措施.
关键词:
球罐
,
NK-HITEN610U2钢
,
SSC
,
焊接接头
Acta Chimica Sinica
Passive film formed on 304 stainless steel in 2.5 mol/L H2SO4 solution by using alternating voltage (A. V.) passivation have been investigated by measuring capacitance and photoelectrochemical parameters. The investigation of the effect of measure frequency on the slope of Mott-Schottky curve has been carried out. The photoelectrochemical measurements were consistent with the capacitance measurement. Analysis of the experimental results showed that the passive film formed 304 stainless steel by using A. V. passivation exhibits semiconducting properties. Using the simple model of semiconductor rather than the multi-donor level model can explain satisfactorily the semiconducting behavior of the film formed on 304 stainless steel by using A.V. passivation.
关键词:
A. V. passivation;passive film;semiconducting properties;stainless;steel;model;electrodes
伏晓国
,
刘柯钊
,
汪小琳
,
柏朝茂
,
赵正平
,
蒋春丽
金属学报
采用X射线光电子能谱(XPS)分析研究了298 K时O2在金属U和U Nb合金清洁表面的原位吸附过程,作为对照还研究了在纯Nb表面的吸附.吸附各阶段XPS图谱的变化揭示了O2在U,Nb和U-Nb合金表面的吸附将导致UO2,NbO和Nb2O5等多种产物形成定量分析表明,O2在U和U-Nb合金表面的饱和吸附量大约分别为45 L和40 L(1 L=L33x10-4Pa.s),而O2在金属Nb上的饱和吸附量仅约为10 L.
关键词:
合金
,
null
,
null
伏晓国
,
刘柯钊
,
汪小琳
,
柏朝茂
,
赵正平
,
蒋春丽
金属学报
doi:10.3321/j.issn:0412-1961.2001.06.004
采用X射线光电子能谱(XPS)分析研究了298 K时O2在金属U和U Nb合金清洁表面的原位吸附过程,作为对照还研究了在纯Nb表面的吸附.吸附各阶段XPS图谱的变化揭示了O2在U,Nb和U-Nb合金表面的吸附将导致UO2,NbO和Nb2O5等多种产物形成定量分析表明,O2在U和U-Nb合金表面的饱和吸附量大约分别为45 L和40 L(1 L=L33x10-4Pa@s),而O2在金属Nb上的饱和吸附量仅约为10 L.
关键词:
O2
,
U
,
U-Nb合金
,
表面吸附
,
X射线光电子谱
Journal of Materials Research
The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.
关键词:
room-temperature
XIE Guoqiang
,
YANG Jijian
,
ZHANG Baisheng
,
LI Wendan(China Institute of Atomic Energy
,
Beijing) Manuscript received 13 December 1994
金属学报(英文版)
U—10wt%Zr alloy has been analysed by neutron diffraction method to determine the constituent phases and their crystal structures.The collected diffraction data are processed using Rietveld' s profile technique (with program“ Fullprof ”). Four phases,α-U,δ, γand α—Zr, in the alloy at room temperature and the corresponding volume fractions as well their structural parameters are obtained from the data analysis, For the δ-phase, a partially ordered unusual hexagonal structure of the modified C32(AlB2) type is confirmed.
关键词:
:U-10wt%Zr alloy
,
null
,
null
Computer Physics Communications
Based on a detailed check of the LDA + U and GGA + U corrected methods, we found that the transition energy levels depend almost linearly on the effective U parameter. GGA + U seems to be better than LDA + U, with effective U parameter of about 5.0 eV. However, though the results between LDA and GGA are very different before correction, the corrected transition energy levels spread less than 0.3 eV. These more or less consistent results indicate the necessity and validity of LDA + U and GGA + U correction. (C) 2012 Elsevier B.V. All rights reserved.
关键词:
Band-gap problems;LDA plus U and GGA plus U;ZnO;First-principles;augmented-wave method
