Zhengrong PAN
金属学报(英文版)
The effects of 0.5 wt pct In on Al-3.3Cu-0.8Li alloy were studied. Instead of T1 (Al2CuLi) phase, there was an unknown cubic phase acting as the dominant precipitates in the In-added alloy in T6 temper, which disappeared in T8 temper. The orientation relationship between this phase and matrix was given by SAEDs: (001)p//(001)α, [010]p//[010]α. Both measuring directly from HREM images or calculating from it's FFTs gave an close lattice parameter about 0.83~nm. 3DAP composition analysis revealed the presence of Al, Cu and Li in the atomic percentages: 60%Al, 30%Cu and 10%Li. Thus, this cubic phase is considered to be Li-rich γ1 (Al4Cu9) phase or a new phase designated as χ (Al5Cu6Li2). Different from the traditional report providing heterogeneous nucleation sites for the precipitates, In was detected neither around nor in the cubic phase by EDX and 3DAP.
关键词:
Indium
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Precipitation
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Microstructure
,
HRTEM
,
3DAP
康强
,
张彩碚
,
赖祖涵
,
宁小光
金属学报
用ＴＥＭ观察了工业纯α－Ｔｉ板渗氢０．２—１．５３ｗｔ－％后析出的氢化物的形态和结构．结果表明：β－Ｔｉ（Ｈ）共析转变产物是δ氢化物和α－Ｔｉ，不同形状的δ氢化物和α－Ｔｉ微晶组成了微晶区；γ氢化物直接从α－Ｔｉ（Ｈ）中析出．用高分辨电子显微术（ＨＲＴＥＭ）观察了β－Ｔｉ（Ｈ）共析转变形成的微晶区的精细结构，表明δ氢化物周围可以存在满足δ氢化物和α－Ｔｉ两种取向关系的１０种α－Ｔｉ变体．本文讨论了β－Ｔｉ（Ｈ）共析转变的切变机制．
关键词:
Ｔｉ－Ｈ合金
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δ hydride
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HRTEM
,
eutectoid transformation
徐永波
无机材料学报
doi:10.3724/SP.J.1077.2009.01081
对压痕诱发脆性材料塑性、损伤与断裂研究进行总结, 并结合与之有关学科研究进展予以评述. 主要结果：微压痕诱导硅和砷化镓晶体的纳米和非晶转变, 并发现这一转变的临界应力; 转变过程是由切应力, 并非静水压力控制; 电子辐照诱导非晶晶化, 并发现晶化临界条件; 晶化速率与电流密度有关; 压痕诱发的裂纹尖端不是原子尖的, 其萌生与扩展伴随位错的产生, 并由此引发点阵的畸变, 并产生1～2nm宽非晶带； 裂纹扩展沿非晶带发生, 而非裂端前方原子键相继断裂的结果; 经傅立叶变换和逆变换发现, 裂纹尖端变形显示出各向异性.
关键词:
微压痕
,
HRTEM
,
crystallization and amorphization
,
crack-tip structure
,
Fast Fourier Transformation (FFT) and Inverse-Fast Fourier Transformation (IFFT)
J. G. Wang
,
L.C Zhang
,
G.L. Chen and H. Q. Ye(State Key Laboratory for Advanced Metals and Materials
,
University of Science and Technology Beijing
,
Beijing 100083
,
China)(Laboratory of Atomic Imaging of Solids
,
Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China)
金属学报(英文版)
High-resolution transmission electron microscope (HRTEM) was employed to investigate the deformation-induced α2→γ phase transformation phenomenon in a hot deformed Ti-45Al-10Nb alloy. Such a tronsformation can be nucleated either at α2/γ interfaces or at stacking faults on the basal planes of the α2 phase. The growth of deformation-induced γplate is accomplished by the motion of α/6<100> Shockley partials on alternate basal planes (0001)α2, and the α/6<100> Shockley partials move in coordination rather than sweep on (0001)α2 plane one by one. It appears that no atom transportation is involved in this stress-induced α2→γ transfromation.
关键词:
intermetallic compound
,
null
,
null
,
null
,
null
,
null
X.L.Zhao1)
,
T.L.Guo2)
,
M.Ohkohchi3)
,
T.Okazaki3)
,
S.Iijima and Y.Ando3) 1) Japan Science and Technology Corporation
,
Department of Physics
,
Meijo University
,
Shiogamaguchi1 501
,
Tempaku ku
,
Nagoya 468 8502
,
Japan 2) Scientific Research Department
,
Shenyang University
,
Wanghuanan Street21
,
Dadong District
,
Shenyang 110044
,
China 3) Department of Physics
,
Meijo University
,
Shiogamaguchi 1 501
,
Tempaku ku
,
Nagoya 468 8502
,
Japan$
金属学报(英文版)
Multiwalled carbon nanotubes ( MWNTs) were prepared by DCarc dischargein hydrogen gas, and werethermally purified byinfrared radiation in air. The morphology of pristineand purified MWNTs was observed by scanning electron microscope ( SEM) , and the crys tallinestructureand perfection wereinvestigated by high resolution transmission electron mi croscope( HRTEM) and Raman spectrometer. Itcameto the conclusion thatthese MWNTs possessed a high degreeof graphitization and very narrow centralchannel(about1 0 nm indiameter) , giving risetotheappearanceof breathing modesfor MWNTs.
关键词:
multiwalled carbon nanotubes
,
null
,
null
,
null
,
null
