X.T.Liu
,
J.Z.Cui
金属学报(英文版)
With an electric field during austenitizing, the martensite transformation of the low carbon steel was promoted, and more martensite were obtained. The electric field promotes the homogeneity of carbon, and reduces the free energy of austenite. The critical neuclus r^* and the critical driving force G^* responsible for the nucleation of proeutectoid ferrite were increased. As a result of which the diffusion controlled proeuctoid ferrite transformation was retarded and the hardenability was improved.
关键词:
austenization
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null
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null
X.T.Liu
,
J.Z.Cui
金属学报(英文版)
Microstructure evolution of wrought aluminum alloy extruded rods and the mechanism of liquid phase formation during reheating were investigated. And the relation between the volume fraction of liquid phase and the recrystallization microstructure was proposed. The results show that increase in reheating temperature and time can augment the volume fraction of liquid phase and accelerate the grain spheroidization, as a result of which the requirement of semi-solid forming can be satisfied. Due to the higher aberration energy of grain boundary, the melting point is lowered as a result of the easy diffusion of atoms. At higher reheating temperature the grain boundary melts, the growth of the recrystallized grain is inhibited and the grain is refined. The composition of the low melt-point phase along the recrystallized grains was determined using EDS. It can be seen from the experimental results that when the extrusion rod of the wrought aluminum alloy is reheated at 610℃ for 20min, perfect fine equiaxial grains can be obtained, the average grain size is about 66.34μm and the volume fraction of solid phase is about 68%.
关键词:
wrought aluminum alloy
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null
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null
