LUO Laizhong ZHANG Jinxiu LIN Guangming Zhongshan University
,
Guangzhou
,
510275
,
China Lecturer
,
Dept.of Physics and Institute of Material Science
,
Zhongshan University
,
Guangzhou
,
510275
,
China
金属学报(英文版)
The snap-action behavior of a Ni-Ti alloy disc which is controlled by combination of a nonlinear stress field and temperature has been studied.After treatment for two-way shape memory,all shape memory strain of snap-action finishes abruptly at a certain temperature within an interval of less than 1 ms.The results of resistance measurement and in-situ X-ray diffraction indicate that the snap-action strain is mainly resulted from the snap-action β (?)R transformation.
关键词:
shape memory alloy
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null
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null
YANG Qiqin LIU Guankun LIU Zejin Zhongshan University
,
Guangzhou
,
China YANG Qiqin
,
Associate Professor
,
Department of Chemistry
,
Zhongshan University
,
Guangzhou
,
China
金属学报(英文版)
The electrochemical alloying of Y-Cu system in molten NaCl-KCl-YCl_3 has been investi- gated.The free energy changes of the formation reactions of the intermetallic compounds,in- cluding YCu_6 ,YCu_4 YCu_2 ,Yfu(973—103 K),were determined by means of electrode potential-time curves of the working electrode after potentiostatic electrolysis.The results in- dicate that the potential-time method is simple and reliable.
关键词:
Y-Cu system
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null
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null
Liu Zhengyi Fu Jian Zhuang Yuzhi South China University of Technology
,
Guangzhou
,
China Correspondent:LIU Zhengyi professor
,
Dept.of Mechanical Engineering No.2
,
South China University of Technology
,
Guangzhou
,
China
金属学报(英文版)
The nature of“white layer”found in 55SiMnMo steel subjected to friction test has been stu- died using TEM,SEM,X-ray diffraction and EPMA techniques.It is shown that the struc- ture of the“white laver”on the rubbing surface is duplex,consisting of a special martensite and some austenite.This layer may be 25—50 μm thick.It is ultrafine,with grain diametric approximately 30 nm.Its micro-hardness may be as high as Hm 1500 and is capable of cut- ting glass.It has superb corrosion resistance and resists tempering.Its mierostructure and hardness undergo changes only when the steel is tempered above 500℃.
关键词:
friction
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null
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LIN Guangming CHENXingyuan ZHANG Jinxiu Material Science Research Institute
,
Zhongshan University
,
Guangzhou
,
China WANG Yurui Metallurgy Research Institute of Beijing Iron and Steel Company
,
Beijing
,
China LIN Guangming Associate Professor
,
Department of Physics
,
Zhongshan University
,
Guangzhou 510275
,
China
金属学报(英文版)
Snap-acting two way shape memory device can be obtained by using the design proposed by authors.Some essential parameters which characterize the properties of device have been pro- posed also in this paper.And the principle and method according to which a practical snap-acting device can be designed have been described.
关键词:
shape memory alloy
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null
,
null
LIU Qiyang LI Qingchun ZHANG Jiren Harbin Institute of Technology
,
Harbin
,
China LIU Qiyang
,
Division of Foundry
,
Department of Mechanical Engineering No.2
,
South China University of Technology
,
Guangzhou
,
China
金属学报(英文版)
By inserting the single crystal silicon seeds into Sr modified Al-22wt-% Si alloy melts,the fact that nucleation and growth of Si-phase are affected by Sr addition has been confirmed.It is suggested that this effect is caused by the adsorption of Sr on{111}_(si),and the modification of eutectic structure results from the variation of leading phase in the eutectic from Si to α-Al.
关键词:
Al-Si alloy
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null
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null
LIN Guangming HUANG Yuanshi ZHANG Jinxiu Zhongshan University
,
Guangzhou
,
China LIN Guangming
,
Associate Professor
,
Dept.of Physics
,
Zhongshan University
,
Guangzhou 510275
,
China
金属学报(英文版)
The snap-acting transition and two way shape memory (TWSM) effect have been obtained in a TWSM spring made of Ni51Ti49 alloy using the constrained effect of stress on driving force of TWSM material.When the snap-acting transition has been realized:M_s= M_f and A_s=A_f;hysteresis is rectangular,the height (TWSM effect) and width (hysteresis) of the rectangle can be readjusted by means of constrained stress.The results of resistance measurments show that,the snap-acting TWSM effect mentioned above was supplied mainly from the transformation of P←→R.The thermodynamic model has also been proposed to ac- count for the snap-acting transformation.
关键词:
transformation thermodynamics
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null
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null
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null
WU Shanghua LIU Yumen Materials Science Institute
,
Zhongshan University
,
Guangzhou
,
510275
,
China.Department of Materials Science and Engineering
,
Xi'an Jiaotong University
,
Xi'an
,
710049
,
China.To whom correspondence should be addressed.
材料科学技术（英文）
The martensitic transformation in Fe-Cr-W-V-C alloy has been investigated by TEM.The habit plane of martensite is near (252)_f, the austenite/martensite orientation relationship is Kurdjumov-Sachs'.In the martensite plates there are twins on (112)[ 1]_b,dislocation tangles and the lattice defects on (011)_b plane.In the austenite near the growing martensite plates,the dislocations with high density and stacking faults can be observed. The substructure of martensite may probably be the result of accommodation deformation during martensitic transformations.
关键词:
martensite
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null
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null
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null
XIAO Jichuang FANG Jianneng South China University of Technology
,
Guangzhou
,
China XIAO Jichuang Associate Professor
,
Dept.of Mechanical Engineering No.2
,
South China University of Technology
,
Guangzhou 510641
,
China
金属学报(英文版)
An investigation was made of the influence of Zr additive on the high temperature phase trans- formations,martensitic forward/reverse transformations,and shape memory effect of Cu-Zn-Al base alloys by means of differential scanning calorimetry(DSC),X-ray diffraction and TEM.It was found that an addition of 0.35 wt-% Zn could effectively inhibit the precipitation of α and γ phases and hence promote the order-martensitic transformations β_2→DO_3→18RM,thus resulting in a minimum activation energy of the martensitic trans- formation and narrow temperature ranges(M_s-M_f)and(A_s-A_f);the alloy so obtained pos- sessed smooth and mobile martensite intervariant interfaces,therefore showing the best shape memory effect.
关键词:
Cu-Zn-Al alloy
,
null
,
null
,
null
LIANG Sizu LIANG Yaoneng LIU Zhengyi South China University of Technology
,
Guangzhou
,
China Lecturer
,
Department of Mechanical Engineering No.2
,
South China University of Technology
,
Guangzhou 510641
,
China
金属学报(英文版)
The fracture surface of the normalized steel 55SiMnMo was observed,under tensile device at- tached on the SEM,to be of ductile dimple feature on the bainite which is composed of lath ferrite and austenite platelet.The dimple is essentially nucleated in the ferrite.Because the austenitic plastic deformation is remarkable during fracturing,the tear ridge of dimple is very sharp.
关键词:
dimple
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null
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null
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null
LUO Chengping(C.P.Luo) ZHAO Fang South China University of Technology
,
Guangzhou
,
China
金属学报(英文版)
A TEM investigation was made on the morphology,orientation relationship and habit plane of three alloy nitrides,namely CrN,VN and Mo_2N simultaneously formed within the diffussional nitrided layers in an H13 steel nitrided at 580℃.It was.found that the nitrides were precipitated by continuous clustering and subsequent ordering of both interstitial(N)and substitutional(Cr,V,Mo)solutes on {001} habit plane,and that the observed morphology and crystallography of the nitrides were in good agreement with the predictions from the invariant line stain model proposed for precipitation transformations.
关键词:
alloy nitride
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null
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null
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null
