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Microstructure and strengthening mechanisms of Mg-6Al-6Nd alloy

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Rare Metals 2010年第1期29卷 55-61页

作者： WU Yufeng DU Wenbo YAN Zhenjie WANG Zhaohui zuo tieyong Institute of Recycling Economy Beijing University of Technology Beijing 100124 China College of Materials Science and Engineering Beijing University of Technology Beijing 100124 China

The microstructure and strengthening mechanisms of as-cast Mg-6Al-6Nd alloy were studied. The results show that the addition of 6 wt.% Nd into Mg-6Al alloy leads to the precipitation of Al11Nd3 and Al2Nd phases and decrease in the content of Al solid soluted in Mg-Al matrix. The volume fractions of Al11Nd3 and Al2Nd phases are 3.64% and 0.34%, respectively. Compared with Mg-6Al alloy, the ultimate strength, yielding strength, and elongation of Mg-6Al-6Nd alloy at room temperature and 175℃ are enhanced in some degrees. The strengthening mechanisms of Mg-6Al-6Nd alloy are mainly composed of solid solution strengthening of Al solid soluted in Mg-Al matrix and grain refmement strengthening, dispersion strengthening, and composite strengthening brought by the precipitation of Al11Nd3 phase. The composite strengthening includes the load transfer from the matrix to Al11Nd3 phase and the enhancement of dislocation density due to the geometrical mismatch and thermal mismatch between the matrix and Al11Nd3 phase.

关键词： magnesium alloys strengthening mechanism quantitative analysis precipitation

THERMIONIC EMISSION OF CARBONIZED La-Mo CATHODE

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中国有色金属学会会刊：英文版 1999年第2期9卷 26-30页

作者： Nie, zuoren Zhou, Meiling Wang, Jinshu Zhang, Jiuxing zuo, tieyong Beijing Polytechnic Univ Beijing China

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｃａｔｈｏｄｅｉｓｔｈｅｃｏｒｅｐａｒｔｏｆｅｌｅｃｔｒｏｎｉｃｄｅｖｉｃｅｂｅｃａｕｓｅｉｔｓｅｒｖｅｓａｓｔｈｅｅｌｅｃｔｒｏｎｒｅｓｏｕｒｃｅａｎｄｉｔｓｑｕａｌｉｔｙｄｉｒｅｃ... 详细信息

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｃａｔｈｏｄｅｉｓｔｈｅｃｏｒｅｐａｒｔｏｆｅｌｅｃｔｒｏｎｉｃｄｅｖｉｃｅｂｅｃａｕｓｅｉｔｓｅｒｖｅｓａｓｔｈｅｅｌｅｃｔｒｏｎｒｅｓｏｕｒｃｅａｎｄｉｔｓｑｕａｌｉｔｙｄｉｒｅｃｔｌｙｉｎｆｌｕｅｎｃｅｓｔｈｅｌ...

关键词： cathoderareearthmolybdenumthermionic emissionLa2O3

EFFECTS OF Y₂O₃ AND CeO₂ ON PROCESSING AND CHARACTERISTICS OF TUNGSTEN ELECTRODES

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中国有色金属学会会刊：英文版 1999年第2期9卷 118-122页

作者： Chen, Ying Nie, zuoren Zhou, Meiling Zhang, Jiuxing zuo, tieyong Beijing Polytechnic Univ Beijing China

１ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｒｅｃｅｎｔｙｅａｒｓ，ｔｕｎｇｓｔｅｎｅｌｅｃｔｒｏｄｅｍａｔｅｒｉａｌｓｃｏｎｔａｉｎｉｎｇｏｎｅｋｉｎｄｏｆｒａｒｅｅａｒｔｈｍｅｔａｌｏｘｉｄｅａｓＬａ２Ｏ３，ＣｅＯ２ａｎｄＹ... 详细信息

１ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｒｅｃｅｎｔｙｅａｒｓ，ｔｕｎｇｓｔｅｎｅｌｅｃｔｒｏｄｅｍａｔｅｒｉａｌｓｃｏｎｔａｉｎｉｎｇｏｎｅｋｉｎｄｏｆｒａｒｅｅａｒｔｈｍｅｔａｌｏｘｉｄｅａｓＬａ２Ｏ３，ＣｅＯ２ａｎｄＹ２Ｏ３，ｈａｖｅｂｅｅｎｄｅｖｅｌ...

关键词： Y2O3CeO2tungsten electrodearcstartingconsumption

Characterization and normalization factors of abiotic resource depletion for life cycle impact assessment in China

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Science China(Technological Sciences) 2009年第1期52卷 215-222页

作者： GAO Feng NIE zuoRen WANG ZhiHong GONG XianZheng zuo tieyong College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

The availability of resources for economic activities differs between regions, and the importance of the resources is consequently observed to be different within regions compared to a global scale. With the current situation in Chinese mining industry and its statistic characteristics, the characterization procedures of abiotic resource in life cycle impact assessment (LCIA) have demonstrated certain limita-tions in the Chinese materials industry. The aim of this paper is to propose new characterization and normalization factors for abiotic resource depletion categories such as metals and non-renewable en- ergy resources in a Chinese context. The actual production of abiotic resources calculated by a modi- fied model is compared to the reserve base in line with the new national standard to determine char- acterization factors in equivalence units, with antimony as the reference mineral. The normalization factors are based on the total base reserves of the most important minerals in China. A case study on primary magnesium production using the Pidgeon process is used to compare LCIA results for abiotic resource categories that are between current LCIA factors and the new Chinese factors. These factors not only reflect the importance of abiotic resource with respect to region-specific resource depletion, but also can compare with the global factors.

关键词： resource depletion abiotic resource categories life cycle impact assessment (LCIA) magnesium production the Pidgeon process China

Research and development of Chinese LCA database and LCA software

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Rare Metals 2006年第z2期25卷 101-104页

作者： GONG Xianzheng NIE zuoren Wang Zhihong zuo tieyong College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China

This paper detailed introduces the related work for building Chinese National Database, Sinocenter, of materials life cycle assessment (MLCA) and developing the environmental burden dataset of materials. The MLCA database was built in 2004, and the basic framework mainly includes LCA methodology, materials environmental dataset about energy consumption, resource input and environmental emissions. Nowadays, the database contains about fifty-thousand records of the main materials industries, such as cement, iron and steel, nonferrous metal, etc., and also includes the primary LCI data of fossil fuels and electricity grid in China. At the same time, the LCA method localization work is going on, for instance, calculated the resource characterization factors of 42 kinds of metal and 58 sorts of nonmetal, and also obtained some heavy metal impact factors in water. Based on the database, the iron and steel dataset has been developed with the data quality analysis, and some environmental burden data could be queried in our website, ***, in the future. Lastly, according to the framework of the ISO14040 series standards, the antitype of Chinese LCA evaluation system was developed to support materials and products LCA evaluation in China.

关键词： database dataset environmental burden data quality LCI

Greenhouse gas emissions and reduction potential of primary aluminum production in China

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Science China(Technological Sciences) 2009年第8期52卷 2161-2166页

作者： GAO Feng NIE zuoRen WANG ZhiHong LI HongMei GONG XianZheng zuo tieyong College of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

A cradle-to-gate life cycle assessment was conducted in this paper to calculate the greenhouse gas (GHG) emissions, such as CO2, CH4, CF4 and C2F6 emissions, based on statistic data of Chinese aluminum industry of the year 2003. The results showed that the GHG emissions for 1 t primary aluminum production was 21.6 t CO2 equivalent which is 70% higher than that of worldwide average level of the year 2000. The main contributors of emission were the alumina refining and aluminum smelting process accounting for 72% and 22% in accumulative emission, respectively. According to the development and application of new process technologies for primary aluminum production and the ‘target of energy-saving and emissions-reducing’ of Chinese government, the reduction potential of the GHG emissions for alumina and aluminum production were estimated. The results indicated that China aluminum industry would achieve the target of reducing about 25% GHG emissions by the end of 2010.

关键词： aluminum metallurgy greenhouse gas energy-saving and emissions-reducing life cycle assessment

TUNGSTEN ELECTRODES CONTAINING THREE TYPES OF RARE EARTH OXIDES

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中国有色金属学会会刊：英文版 1999年第1期9卷 38-41页

作者： Nie, zuoren Zhou, Meiling Chen, Ying Fan, Xiaowu Zhang, Jiuxing zuo, tieyong Beijing Polytechnic Univ Beijing China

ＩＮＴＲＯＤＵＣＴＩＯＮＷｉｔｈｉｎｃｒｅａｓｉｎｇｄｅｍａｎｄｓｔｏｔｈｅｐｒｏｐｅｒｔｙｏｆｗｅｌｄｉｎｇｅｌｅｃｔｒｏｄｅａｎｄｂｅｔｅｒｋｎｏｗｌｅｄｇｅｏｆＴｈＷｅｌｅｃｔｒｏｄｅｍａｔｅｒｉａｌ’ｓｒａ... 详细信息

ＩＮＴＲＯＤＵＣＴＩＯＮＷｉｔｈｉｎｃｒｅａｓｉｎｇｄｅｍａｎｄｓｔｏｔｈｅｐｒｏｐｅｒｔｙｏｆｗｅｌｄｉｎｇｅｌｅｃｔｒｏｄｅａｎｄｂｅｔｅｒｋｎｏｗｌｅｄｇｅｏｆＴｈＷｅｌｅｃｔｒｏｄｅｍａｔｅｒｉａｌ’ｓｒａｄｉｏａｃｔｉｖｉｔｙ，ｓｏｍｅｓ...

关键词： rare earth oxides tungsten electrode welding rim Y 2O 3+La 2O 3+CeO 2

A review on scandia doped tungsten matrix scandate cathode

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Tungsten 2019年第1期1卷 91-100页

作者： Jinshu Wang Yunfei Yang Yiman Wang Wei Liu Meiling Zhou tieyong zuo College of Material Science and Engineering Key Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaBeijing University of TechnologyBeijing 100124China

As the cathode with the highest electron emission capability in the thermionic cathode,the scandate cathode has attracted more and more attention in recent years,especially the scandia doped tungsten matrix scandate *** studies show that scandia doped tungsten matrix scandate cathodes with submicron microstructures exhibit excellent emission capacity,and the pulse emission current density in the space-charge region can be over 35 A cm^(−2) at 850°*** the direct current(DC)condition with temperature compensation,the emission current density could reach 25 A cm^(−2) at 850°*** device lifetime is over 3700 h after operating at 950°C_(b) with the DC loading of 40 A cm^(−2).The emission mechanism of the scandate cathode including the effect of the surface structure and composition on the work function of the cathode are systematically reviewed.

关键词： Scandate cathode Tungsten Electron emission Microstructure Surface analysis

PHYSICAL METALLURGY OF MULTISTAGE RSP Al-Li BASED ALLOYS

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维普期刊数据库

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Transactions of Nonferrous Metals Society of China 1992年第1期2卷 77-83,97页

作者： Yin,Zhimin Zhang,Xinmin Chen,Zhenhua zuo,tieyong Central-South University of Technology Changsha 410083China

Bascd on serires authors study ofAl—Li alloys in recent years,the formation theory of powders,characteristics,powder compaction,the microstructures and the mechanical behaviors of RSP Al-Li based alloys analyzed and ... 详细信息

关键词： Rapid Solidification Al-Li alloy Powder metallurgy microstructure mechanical property