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Morphology of the Cu‐rich Phase in Cu‐Pb Hypermonotectic Alloys under an Intense Magnetic Field
Author(s) -
Wang Engang,
Zhang Lin,
Zuo Xiaowei,
He Jicheng
Publication year - 2007
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.200705908
Subject(s) - alloy , microstructure , phase (matter) , materials science , spheres , shell (structure) , diffusion , matrix (chemical analysis) , spherical shell , sedimentation , magnetic field , morphology (biology) , analytical chemistry (journal) , metallurgy , composite material , thermodynamics , chemistry , geology , physics , chromatography , paleontology , organic chemistry , quantum mechanics , astronomy , sediment
The solidification structure of a Cu‐80wt%Pb hypermonotectic alloy was investigated under four different experimental conditions. The results show that the spherical Cu‐rich phase in the matrix has three kinds of morphology, that is the larger “net‐shell type” and the smaller “egg‐type” or “eye‐type”. The cooling rate of the samples has a great effect on both macrostructure and microstructure. As the cooling rate becomes slow, the Cu‐rich phase changes from fine spheres to larger floating spheres and finally to coarse dendrites, and the thickness of the Cu‐shell and the net of Cu‐Pb phase in the Cu‐rich spheres become coarser. A magnetic field of 12 T has a remarkable effect: it restrains the gravity segregation of the Cu‐Pb alloy by preventing the floating of the larger Cu‐rich droplets and the sedimentation of the Pb‐matrix. Thus, the Cu‐Pb monotectic alloy exhibits a macrostructure and microstructure which are similar to those obtained at relatively fast cooling rates. The 12T magnetic field is supposed to restrain the collection of solute Cu extracted from the liquid Pb phase and the diffusion of solute Cu to the Cu‐shell in the centre of larger Cu‐rich droplets.