LIU Ning CUI Kun Huazhong University of Science and Technology
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Wuhan.China DENG Zonggang Hefei University of Technology
,
Hefei
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China CHENG Benpei KONG Jie Institute of Solid State Physics
,
Academia Sinica
,
Hefei
,
China Doctorate student
,
Department of Mechanical Engineering No.2
,
Huazhong University of Science and Technology
,
Wuhan 430074
,
China
金属学报(英文版)
Microstructure of the deepest zone of high speed steel W6Mo5Cr4V2(M2)melt after laser fu-sion was found to be so fine as the ehill zone of a solidified ingot.When narrower chill zoneformed,the long columnar dendrites grow into the melt and then the fine equiaxed cellularstructure appears in upper melt region nearly surface.The substructure of cellular grains anddendrites was observed to consist of martensite and retained austenile,while the carbides asM_6C_■ Cr_7C_3 and MC distributed at their boundaries.It is believed that the highermicrohardness up to HV_(0.1)=865-960 of the laser fused structure of the alloy is due to the oc-currence of martensite.
关键词:
High speed steel W6Mo5Cr4V2(M2)
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XIA Zhenhai Hebei Institute of Technology
,
Tianjin
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ChinaMAO Zhiying ZHOU Yaohe Northwestern Polytechnical University
,
Xi'an
,
China Doctor
,
Faculty of Foundry
,
Department of Mechanical Engineering No.2
,
Hebei Institute of Technology
,
Tianjin 300132
,
China
金属学报(英文版)
On the basis of fluid kinetics,a model for infiltration kinetics of liquid metals into fibre pre- fabricated composite has been proposed.The infiltration processing,together with the measurements of infiltrating velocity and permeability,for the C fibre-reinforced Al matrix composites have been studied.The model proposed seems to be in good agreement with the ex- perimental results.Two different infiltration modes,uniform and non-uniform,were found and a new technique was suggested.Thus,the quality composites of C fibre-reinforced Al may be made under low pressure regardless of non-wettability of liquid metal to the fibres.
关键词:
liquid metal
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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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XIE Changsheng SUN Peizhen ZHAO Jiansheng CHEN Yuqiu Huazhong University of Science and Technology
,
Wuhan
,
China XIE Changsheng Associate Professor
,
Department of Mechanical Engineering No.2
,
Huazhong University of Science and Technology
,
Wuhan 430074
,
China
金属学报(英文版)
The microstructures of Fe-Mn-Ni-Cr steels with medium carbon and the effect of alloy ele- ments on them have been investigated by means of X-ray diffraction quantitative phase ana- lyses,metallography and hardness tests.The volume fraction of martensite in steels quenched at 1100℃ can be expressed as: f_M~(1100)=162.643-15.482Mn-7.36Ni-4.286(Cr+Mo+V) Based on this expression,the quasi-equilibrium microstructure diagram has been obtained.It is shown that the effect of Mn on the austenite stability is greater than that of Ni.The equiva- lent [Ni]=2.104Mn+Ni and equivalent [Cr]=Cr+Mo+V. The driving force for martensite transformation at M_s point has been calculated to he drastically decreased by element Mn.
关键词:
quasi-equilibrium microstructure diagram
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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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