SUN Enxi Dalian Railway College
,
Dalian
,
ChinaYANG Dazhi Dalian University of Technology
,
Dalian
,
ChinaXU Zuyao (T.Y.Hsu) Shanghai Jiaotong University
,
Shanghai
,
ChinaYANG Fuming ZHAO Ruwen Institute of Physics
,
Academia Sinica
,
Beijing
,
China YANG Dazhi
,
Professor
,
Dalian University of Technology
,
Dalian 116024
,
China
金属学报(英文版)
The pulsed magnetic field induced martensitic transformation with isothermal and athermal kinetics in Fe-2Ni-4Mn(wt-%)alloy has been studied by means of magnetization measurements,optical microscopy and thermodymical analyses.It is shown that there exits a critical magnetic intensity for induing martensitic transformation at a given temperature above Ms.The critical magnetic field increases linearly with increasing ΔT= T-M_S.The magnetic field strongly promotes the athermal martensitic transforamtion and restrains the isothermal one.The entropy change ΔS for athermal transformation at Ms is 4.13 J/mol· K.The effect of magnetic field on martensitic transformation in Fe-21Ni-4Mn alloy is main- ly due to Zeeman effect.Lath,plate and butterfly martensities were observed under magnetic field.
关键词:
magnetic field-induced martensitic transformation
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YU Yongsi CAO Zhiben WANG Fugang
,
Dalian University of Technology
,
Dalian
,
ChinaGUO Xiaobing Jinzhou Institute of Technology
,
Jinzhou
,
China Associate Professor
,
Dept.of Materials Science
,
Dalian University of Technology
,
Dalian 116024
,
China
金属学报(英文版)
The volume fraction of the lamellar carbide cell in HK50 alloy may be increased with the in- crease of nitrogen content over 0.065%.The habit plane of l(?)mellar carbide is {111}_γ.The distribution of nitrogen changes no more before or after the precipitation of lamellar structure. The diffusion activation energy of carbon reduces remarkably with the increase of nitrogen content.It is believed that the lamellar carbide cell is harmful to the high temperature creep and impact properties of the alloy.
关键词:
alloy HK50
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ZHU Min LI Guobin YANG Dazhi Dilian University of Technology
,
Dalian
,
China Dept.of Materials Engineering
,
Dalian University of Technology
,
Dalian 116024
,
China
金属学报(英文版)
The transmission electron microscopy has been used to investigate the fine structure variation of 18R martensite under deformation in a polycrvstalline CuZnAl shape memory alloys.It has been found that the strain is gabined by the reorientation of martensite variants in the ini- tial deformation stage.In addition to the result of optical microscopy studies,however,the reorientation is often incomplete and the interfaces among the prior variants still remain.A lot of twins will appear in martensite under enormous deformation,and the twin plane is(001) phane of martensite lattice.The dislocations has also been observed in some regions.In this case,the martensite will lose its thermoelasticitv and the shape memory effect will be damaged.
关键词:
fine structure
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