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Hydrogenation behaviors and characteristics of bulk Ti-6Al-4V alloy at different isothermal temperatures

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Rare Metals 2019年第12期38卷 1131-1135页

作者： Long Pan Chun-Ming Wang su-fen Xiao Yun-Gui Chen School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065China College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

The bulk Ti-6Al-4V alloy was hydrogenated at the temperature range of 723-973 K,and the hydrogen absorption characteristics and hydrogen absorption kinetics were *** results show that there are two types of hydrogen absorption characteristics at different *** hydrogen content decreases,and the time reaching reaction equilibrium is shorten with the isothermal hydrogenation temperature ***,the mechanism of the hydrogen absorption kinetics is different at different *** incubation period exists at the initial hydrogen absorption stage below 823 K,and K(a2)(the reaction rate constant of Stage 2)>>K(a1)(the reaction rate constant of Stage 1).And there is no incubation period over 823 K,K(a1)>>K(a2).

关键词： Bulk Ti-6Al-4V alloy Hydrogen content Hydrogen absorption kinetic Temperature

Effects of final rolling temperature and coiling temperature on precipitates and microstructure of high-strength low-alloy pipeline steel

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Journal of Iron and Steel Research International 2022年第8期29卷 1236-1244页

作者： Ya-dong Wang Zheng-hua Tang su-fen Xiao Charles WSiyasiya Tao Wei Department of Materials Science and Engineering Sichuan UniversityChengdu 610065SichuanChina Department of Materials Science and Metallurgical Engineering University of PretoriaPretoria 0028South Africa

The strength-to-weight ratio is an important property of high-strength low-alloy(HSLA)steel in pipeline,whose precipitation strengthening can be *** final rolling temperature(FRT)and coiling temperature(CT)are the key process parameters in the control of precipitates and *** cooling rate was fixed at 10℃/s,and the effects of deformation and coiling temperatures on precipitates and microstructure of Ti-Nb microalloyed HSLA steel were investigated through thermo-mechanical controlled processing on Gleeble *** microstructure is mainly acicular ferrite with high density dislocation and several microns *** size and volume fraction of the precipitates were studied under transmission electron *** results showed that the diameter of the precipitates was in the range between 4 and 240 *** optimized combination of parameters is FRT of 820℃and CT of 550℃,and the volume fraction of precipitates obtained under this process is 0.59%.

关键词： Precipitate Thermo-mechanical controlled processing Final rolling temperature Coiling temperature High-strength low-alloy steel (Ti,Nb)C

Effect of manganese sulfide on the precipitation behavior of tin in steel

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 654-659页

作者： Gui-lin sun Bo Song Ling-zhi Yang su-fen Tao Yong Yang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Department of Metallurgical Technology

Tramp elements such as tin are considered harmful to steel because of hot brittleness they induce at high temperatures. Because tramp elements retained in steel scrap will be enriched in new steel due to the difficultly of their removal, studies on the precipitation behavior of tin are essential. In this study, the effects of different inclusions on the precipitation behavior of tin in steel were studied. The results show that the tin-rich phase precipitates at austenite grain boundaries in an Fe-5%Sn alloy without MnS precipitates, whereas Sn precipitates at the boundaries of MnS inclusions in steel that contains MnS precipitates. MnS is more effective than silicon dioxide or aluminum oxide as a nucleation site for the precipitation of the tin phase, which is consistent with the disregistry between the lattice parameters of the tin phase and those of the inclusions.

关键词： steelmaking manganese sulfide tin precipitation heterogeneous nucleation

Transboundary eco-security and its regulation system in the Longitudinal Range-Gorge Region

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Chinese Science Bulletin 2007年第A2期52卷 1-9页

作者： HE DaMing LIU Jiang HU JinMing fen Yan GAN su Asian International Rivers Center Yunnan University Kunming 650091 China

这份报纸讨论了 transboundary eco 安全问题，他们的分发模式，特征和驱动力，和在纵的范围峡区域(LRGR ) 的规定系统。除了沙灰尘暴风雨，主要 transboundary eco 安全问题能在 LRGR 沿着中国的陆上的边阶区域被发现。直接驱动力包括... 详细信息

这份报纸讨论了 transboundary eco 安全问题，他们的分发模式，特征和驱动力，和在纵的范围峡区域(LRGR ) 的规定系统。除了沙灰尘暴风雨，主要 transboundary eco 安全问题能在 LRGR 沿着中国的陆上的边阶区域被发现。直接驱动力包括了串联水力发出的电力水坝，高速公路和国际航行开发的构造，斜坡陆地耕作和矿物质探索。Transboundary eco 安全问题沿着国际水路在陆上的区域，和下游的国家影响附近的区域。在邻国的生态的变化在 LRGR 在国内方面上有效果，例如种类侵略。综合措施应该被考虑，包括边阶 eco 保护工程和 transboundary 自然保护区的构造，生态的阀值安装，种类侵略控制，监视平台的 eco 安全的建立，组成生态的赔偿机制和法律(规则) 并且机构，和能力大楼。在 LRGR 处理 transboundary 问题的最重要的任务是国际性地形成参与合作机制，为 transboundary eco 安全建立资金，实现生态的赔偿策略，并且开发信息交换站台和警告系统。

关键词：生态系统纵向岭谷区分配模式生态安全

A compilation of known QSOs for the Gaia mission

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Research in Astronomy and Astrophysics 2019年第2期19卷 151-160页

作者： Shi-Long Liao Zhao-Xiang Qi su-fen Guo Zi-Huang Cao Shanghai Astronomical Observatory Chinese Academy of Sciences School of Astronomy and Space Science University of Chinese Academy of Sciences National Astronomical Observatories Chinese Academy of Sciences

Quasars are essential for astrometry in the sense that they are spatially stationary because of their large distance from the sun. The European Space Agency(ESA) astrometric satellite Gaia is scanning the whole sky with unprecedented accuracy up to the level of a few μas. However, Gaia's two-fields-ofview-observation strategy may introduce a parallax bias in the Gaia catalog. Since it presents no significant parallax, a quasar is the perfect natural object to detect such bias. More importantly, quasars can be used to construct a celestial reference frame in the optical wavelengths for the Gaia mission. In this paper, we compile a list of known quasars that have been published in the literatures. The final compilation(designated as Known Quasars Catalog for Gaia mission, KQCG) contains 1 842 076 objects, among which797 632 objects are found in Gaia DR1 after cross-identifications. Redshift, color information and position uncertainties of the objects are also provided if available. This catalog will be very useful for the Gaia mission.

关键词： quasars:general astrometry parallaxes proper motions reference systems catalogs

Oxidation behavior of Nb–24Ti–18Si–2Al–2Hf–4Cr and Nb–24Ti–18Si–2Al–2Hf–8Cr hypereutectic alloys at 1250°C

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Rare Metals 2017年第3期36卷 168-173页

作者： Zhen Hong Hu Zhang Jun-Fei Weng Lin-fen su Zhen Li Li-Na Jia School of Materials Science and Engineering Beihang UniversityBeijing 100191China

Nb-24Ti-18Si-2Al-2Hf-4Cr and Nb-24Ti-18Si-2Al-2Hf-8Cr alloys were prepared by arc melting in a water-cooled crucible under argon *** characteristics and oxidation resistance of the alloys at 1250 ℃ were *** results show that,when the Cr content is 4 at%,the microstructures consist of （Nb,Ti）ss and Nb5Si3;as Cr content increases to 8 at%,C14 Laves phase Cr2Nb is *** isothermal oxidation tests show that the oxidation kinetics of the two alloys follow similar *** weight gains of the two alloys after oxidation at 1250 ℃ for 100 h are 235.61 and 198.50 ***-2,*** oxidation,SiO2,TiO2,Nb2O5 and CrNbO4 are formed at ***,Ti2Nb10O29 is formed after oxidation for 20 min and begins to change into TiNb2O7 as the oxidation ***2 is formed as solid state at first but later evolves into glassy state to improve the cohesion of the *** oxidation for 100 h,oxidation products consist of SiO2,TiNb2O7,Nb2O5 and CrNbO4.

关键词： Nb-Si-based alloy lntermetallics Microstructural characteristics Oxidation

Microstructures and high-temperature oxidation behavior of directionally solidified Nb-Si-based alloys with Re additions

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Rare Metals 2023年第1期42卷 273-280页

作者： Jie-Chao Zhang Li-Na Jia Jun-Fei Weng Lin-fen su Bin Kong Hu Zhang School of Materials Science and Engineering Beihang UniversityBeijing100191China

High-temperature oxidation behavior of directionally solidified(DS) Nb-Si-based alloys with Re additions was investigated at 1200 and 1250℃,*** and high-temperature oxidation behavior of the alloys were *** show that the microstructures in vertical section of Nb-24Ti-15Si-4Cr-2Al-2Hf-xRe(x=0,1,3;at%) alloys grow parallel to the withdrawal direction and the cross section exhibits bud-like *** bud-like structures become finer with more Re *** weight gain of the Nb-24Ti-15Si-4Cr-2Al-2Hf-3Re alloy after oxidation at 1200℃ for 100 h is 198.1 mg·cm^(-2),and it is a bit higher at 1250℃.The other two alloys perform somewhat *** influence of Re addition on the oxidation resistance at 1250℃ is more significant than that at 1200 ℃.Although Re addition does not benefit obviously the high-temperature oxidation resistance of the DS samples,it does not compromise the oxidation resistance with a certain amount of Re additions in contrast with the alloy without Re addition.

关键词： Nb-Si alloys Directional solidification Rhenium addition Oxidation behavior Microstructure

Effects of hot compression deformation temperature on the microstructure and properties of Al–Zr–La alloys

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International Journal of Minerals,Metallurgy and Materials 2018年第2期25卷 236-243页

作者： Xian-hua Yue Chun-fang Liu Hui-hua Liu su-fen Xiao Zheng-hua Tang Tian Tang College of Materials Science and Engineering Sichuan University TBEA Deyang Cable Stock Co. Ltd.

The main goal of this study is to investigate the microstructure and electrical properties of Al–Zr–La alloys under different hot compression deformation temperatures. In particular, a Gleeble 3500 thermal simulator was used to carry out multi-pass hot compression tests. For five-pass hot compression deformation, the last-pass deformation temperatures were 240, 260, 300, 340, 380, and 420°C, respectively, where the first-pass deformation temperature was 460°C. The experimental results indicated that increasing the hot compression deformation temperature with each pass resulted in improved electrical conductivity of the alloy. Consequently, the flow stress was reduced after deformation of the samples subjected to the same number of passes. In addition, the dislocation density gradually decreased and the grain size increased after hot compression deformation. Furthermore, the dynamic recrystallization behavior was effectively suppressed during the hot compression process because spherical Al;Zr precipitates pinned the dislocation movement effectively and prevented grain boundary sliding.

关键词： microstructure Al–Zr–La alloys hot compression deformation dislocation

Structure and Texture Formation During Single and Double Cold Rolling and Annealing Processes for Nb+Ti Added Interstitial-Free Steels

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Journal of Iron and Steel Research International 2013年第5期20卷 42-49页

作者： fenG Yan-qing WANG Fu-ming TAO su-fen ZHAO Dian-qing ZHANG Xiao-yan State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Baotou Iron and Steel (Group) Co. Ltd.

The structure and texture formation for single cold rolling （SCR） with annealing and double cold rolling （DCR） with annealing were investigated based on optical microscope and X-ray diffraction （XRD） with a Nb＋Ti bearing interstitial free （IF） steel. The results indicated that DCR recrystallization grain was smaller than that of SCR sample and double cold rolling process resulted in better mechanical properties than those resulted from single cold rolling process with the same total reduction conducted. The plastic strain ratio increases from 2.23 for single cold rolling process to 3.2 for double rolling process. The fish-bone structure was observed in all SCR and DCR samples. DCR annealed sample is made up of equiaxed grains of almost uniform size, whereas SCR annealed sample shows a duplex grain structure, consisting of both large and small-sized grains. （Ti＋Nb）C and Fe（Ti＋Nb）P type precipitates were very rarely observed in SCR annealed and DCR annealed steels. The intensity of {111}∥ND for the DCR annealing was higher than that for SCR annealing.

关键词： single cold rolling double cold rolling Nb Ti IF steel structure texture