材料期刊网

MODIFICATION EFFECT OF Sr ON Al-Si ALLOYS

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 , null , null

EFFECT OF Zr ON PHASE TRANSFORMATION IN Cu-Zn-Al SHAPE MEMORY ALLOYS

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

DIMPLE FORMATION ON FRACTURE SURFACE OF STEEL 55SiMnMo

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 , null , null , null

FRICTION MARTENSITE AND ITS TEMPERING CHARACTERISTICS

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 , null , null

Recent Advances of Laser Coating Technology in China

LIANG Yong LI Ruiguo Institute of Metal Research , Academia Sinica , Shenyang 110015 , ChinaInstitute of Corrosion and Protection of Metals , Aademia Sinica , Shenyang , 110015 , China

材料科学技术（英文）

Recent advances in laser coating technology including laser cladding,laser surface alloying and laser vapour deposition in China are reviewed in this paper.

关键词: laser , null , null , null , null

University of Science and Technology Beijing

JIA Shizhen University of Science and Technology Beijing , China.

材料科学技术（英文）

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CORRELATION BETWEEN STRESS COMPONENTS AND STRESS CORROSION CRACKS IN BRASS Lecturer,Department of Materials Physics,University of Science and Technology Beijing,Beijing 100083,China

QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing , Beijing , China

金属学报(英文版)

The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.

关键词: stress corrosion cracking , null , null , null

Abstracts of papers from Journal of University of Science and Technology Beijing

稀有金属（英文版）

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Huazhong University of Science and Technology(H.U.S.T)

材料科学技术（英文）

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Geochemistry of Rare Earth Elements in Xikeng Ag-Pb-Zn Ore Deposit, South Anhui, China

稀土学报(英文版)

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