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Refining Effect of Boron on Hypoeutectic Al-si Alloys

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Journal of Materials Science & Technology 2000年第5期16卷 517-520页

作者： Li WANC+ and xiufang BIAN (Shandong University of Technology, Jinan 250061, China) Shandong University of Technology Jinan 250061 China

Several concepts of the grain refinement mechanism of B on hypoeutectic Al-si alloys have been adopted: the refining effect of B on the a-AI and eutectic si with the different additions of Al-B master alloys made at 850℃ was investigated; and the Al-B master alloys formed under different temperature conditions have been studied to explore the morphologies of AIB2 particles; slowly cooled sample with addition of Al-B was made to explore the refinement mechanism. AI-B master alloy can refine not only a-AI, but eutectic si. Theoretical analysis indicates that, although AIB2 does not take part directly in the nucleation process in pure Al in the presence of si, it provides a substrate for precipitation of a small content of si from which a-At will grow without any undercooling. When the temperature decreases to eutectic line, AIB2 subsequently nucleates eutectic si; AIB2 particles appear in two different morphologies, namely, hexagonal platelet and tetradehedron morphology which depend on the processing temperature conditions.

关键词： Al Refining Effect of Boron on Hypoeutectic Al-si Alloys si

UHV/CVD Low-Temperature si Epitaxy Used for siGe HBT

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Journal of Rare Earths 2004年第Z2期22卷 30-34页

作者： Huang Wentao Shen Guanhao Li Xiyou Chen Changchun Zhang Wei Liu Zhihong Chen Peiyi Tsien Peihsin Institute of Microelectronics Tsinghua UniversityBeijing 100084China Institute of MicroelectronicsTsinghua UniversityBeijing 100084China Institute of MicroelectronicsTsinghua UniversityBeijing 100084China Institute of MicroelectronicsTsinghua UniversityBeijing 100084China Institute of MicroelectronicsTsinghua UniversityBeijing 100084China Institute of MicroelectronicsTsinghua UniversityBeijing 100084China Institute of MicroelectronicsTsinghua UniversityBeijing 100084China Institute of MicroelectronicsTsinghua UniversityBeijing 100084China

Low-temperature-epitaxy n-type silicon layers were grown on arsenic-doped n+-type silicon substrate by using ultra-high vacuum chemical vapor deposition (UHV/CVD). The transition region thickness of the si layers grown under different PH3 flux and different growth temperature were investigated by spreading resistance probe. Results showed that the growth temperature had remarkable influence on the arsenic diffusion from the si substrate. The thicknesses of the transition region were 0.16 μm grown at 700 ℃ and 0.06 μm grown at 500 ℃, respectively. Moreover, the dopant profiles were very abrupt. X-ray diffraction investigation of the epitaxial si layer showed the quality of si layer was very high.siG e HBT device was fabricated by using a revised double-mesa polysilicon-emitter process. Tests show that the CB-junction breakdown characteristic of the siGe HBT is very hard, and the leakage current is only 0.3 μA under a reverse voltage of - 14.0 V. The siGe HBT device had also good output performance, and the current gain is 60.

关键词： UHV/CVD low temperature si epitaxy dopant profile siGe HBT

Characteristics of Faigue Crack Initiation in Ti-5Al-4Sn-2Zr-1Mo-0.7Nd-0.25si Alloy

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Journal of Materials Science & Technology 1997年第3期13卷 238-240页

作者： Jiafeng LEP Yuyin LIU Shaoxuan GUAN Qingjiang WANG Zhongguang WANG Dong LI and Zhuangqi HU(State Key Lab. for Fatigue and Fracture of Materials, Institute of Metal Research, Chinese Academy of Sciences,Shenyan 110015, China) State Key Lab. for Fatigue and Fracture of Materials Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The characteristics of fatigue crack initiation in Ti-5AI-4Sn-2Zr1Mo-O.7Nd-O.25si alloy wereStudied. Two modes Of fatigue crack initiation were found. The Nd-rich phase particles displaybetter resistance to fatigue cr... 详细信息

关键词： Sn Mo Characteristics of Faigue Crack Initiation in Ti-5Al-4Sn-2Zr-1Mo-0.7Nd-0.25si Alloy Zr Ti Al Nd si

Factors Affecting Transformation Temperatures in Fe-Mn-si-Cr-Ni Shape Memory Alloy

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Journal of Materials Science & Technology 2000年第5期16卷 537-539页

作者： Yuhua WEN+, ding LI and Mingjing TU (Department of Materials Shaping and Controlling Engineering, sichuan University, Chengdu 610065, China) Department of Materials Shaping and Controlling Engineering Sichuan University Chengdu 610065 China

The effects of prestrain and annealing temperature on phase transformation temperatures in Fel4Mn5si8Cr4Ni shape memory alloy have been studied. The results showed that when the annealing temperature was 673 K, both the At and the Ms temperatures increased appreciably as the prestrain increased, the As temperature increased slightly with increasing prestrain; the resistivity difference at 303 K between the heating and cooling curve also increased with increasing prestrain, which agreed with the recovery strain. The shape memory effect in Fe-Mn-si-Cr-Ni shape memory alloy is caused by the stress-induced γ→ε martensite transformation and its reverse transformation. When the prestrain was 10%, the Ms temperature decreased remarkably as the annealing temperature increased.

关键词： Factors Affecting Transformation Temperatures in Fe-Mn-si-Cr-Ni Shape Memory Alloy Fe Mn Cr Ni si

THERMAL　RATE　TREATMENT　AND　ITS　EFFECT　ON　MODIFICATION　OF　Al-si　ALLOYS

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中国有色金属学会会刊：英文版 1997年第1期7卷 138-142页

作者： Geng, Haoran Ma, Jiaji Bian, Xoufang Shandong Univ of Technology Ji'nan China

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ＴＨＥＲＭＡＬＲＡＴＥＴＲＥＡＴＭＥＮＴＡＮＤＩＴＳＥＦＦＥＣＴＯＮＭＯＤＩＦＩＣＡＴＩＯＮＯＦＡｌＳｉＡＬＬＯＹＳ①ＧｅｎｇＨａｏｒａｎ，ＭａＪｉａｊｉ，ＢｉａｎＸｏｕｆａｎｇＣｏｌｌｅｇｅｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｒ...

关键词： Al si alloys thermal rate treatment modification alloy melt

Dark output characteristic of γ-ray irradiated CMOS digital image sensors

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Rare Metals 2002年第1期21卷 79-84页

作者： MENG Xiangti and KANG A iguo Institute of Nuclear Energy Technology, Tsinghua University, Beijing 100084, China Institute of Nuclear Energy Technology Tsinghua University 北京 100084

The quality of dark output images from the CMOS (complementarymetal oxide semiconductor) black and white (B & W) digital imagesensors captured before and after γ-ray irradiation was studied. Thecharacteristic parameters of the dark output images captured atdifferent radiation dose, e.g. average brightness and itsnon-uniformity of dark out- put images, were analyzed by our testsoftware. The primary explanation for the change of the parameterswith the radi- ation dose was given.

关键词： CMOS digital image sensor gamma radiation dark output characteristic si

Shape Memory Effect of As-aged Fe-14Mn-5si-8Cr-4Ni-0.2C Alloy

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Journal of Materials Science & Technology 2000年第4期16卷 424-426页

作者： Yuhua WEN, Ning LI and Mingjing TU (Department of Materials Shaping and Controlling Engineering, sichuan University, Chengdu 610065, China) Department of Materials Shaping and Controlling Engineering Sichuan University Chengdu 610065 China

The effects of aging temperature on shape memory effect, mechanical properties and microstruc-ture of Fe-14Mn-5si-8Cr-4Ni-0.2C shape memory alloy have been studied. The results showed that the second phase particles rich in chromium, manganese and silicon precipitate during aging, and thereby increase the hardness and strength of the alloy. The shape recovery ratio can be remarkably improved by aging and a maximum value can be obtained at 1223 K, which is 68% higher than that of the specimen in solid solution state. When the aging temperature is below 1223 K, the amount of second phase particles increases as the aging temperature increases. The size of austenite grain increases with increasing aging temperature. When the temperature is over 1223 K, the second phase particles can not precipitate. The lack of second phase particles and the increase of grain size make the hardness and shape recovery ratio drastically decrease, when the temperature is over 1223 K.

关键词： Mn Shape Memory Effect of As-aged Fe-14Mn-5si-8Cr-4Ni-0.2C Alloy As Fe Cr Ni si

Positron Annihilation Study on the Microstructural Stability in Rapidly Solidified Al_(92.3)Fe_(4.3)V_(0.7)si_(1.7)Mm_(1.0) Alloy

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Journal of Materials Science & Technology 1998年第2期14卷 179-181页

作者： Wei JIA Meikuang Tseng and Jianqiang WANG(Dept. of Material Science, Northeastern University Shenyang 110006, China)Liangyue XIONG and Yelong CHU(International Ceoter for Materials Physics, Institute of Metal Research, Chinese Academy of Sciences,Shenyan Dept. of Material Science Northeastern University Shenyang 110006 China International Center for Materials Physics Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

Rapidly solidified Al92.3Fe4.3V0.7si1.7Mm1.0 alloy has been studied by positron lifetime spectroscopy and the variations on the intedecial defects with the annealing temperature were revealed by an analysis of the lifetime results. The intedece characteristics derived from the positron-lifetime results could be used to give a satisfactory interpretation of the dependence of mechanical properties on the annealing temperature

关键词： Fe Positron Annihilation Study on the Microstructural Stability in Rapidly Solidified Al Mm si

Electron Transport Properties of Two-Dimensional si_1P_1 Molecular Junctions

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Chinese Physics Letters 2017年第2期34卷 88-91页

作者：高瑞方苏文勇王锋冯万祥 School of Physics Beijing Institute of TechnologyBeijing 100081

We focus on two new 21） materials, i.e., monolayer and bilayer silicon phosphides （sil P1）. Based on the elastic- scattering Green＇s function, the electronic-transport properties of two-dimensional monolayer and bilayer Au- si1P1-Au molecular junctions are studied. It is found that their bandgaps are narrow （0.16eV for a monolayer molecular junction and 0.26 e V for a bilayer molecular junction）. Moreover, the calculated current-voltage char- acteristics indicate that the monolayer molecular junction provides constant output current （20 hA） over a wide voltage range, and the bilayer molecular junction provides higher current （42 hA）.

关键词： Electron Transport Properties of Two-Dimensional si1P1 Molecular Junctions si