Microscopic characterization of semi-solid aluminium alloys

Ya-lin Lu1,2),Miao-quan Li1),Xing-cheng Li2),and Xiao-ping Li2) 1) School of Materials Science and Engineering,Northwestern Polytechnical University,Xi’an 710072,China 2) School of Materials Engineering,Jiangsu Teachers University of Technology,Changzhou 213000,China

摘 要：The microstructural evolution and element distribution of the Al-4Cu-Mg alloy during semi-solid compression were investigated,and the precipitate behavior and dislocation morphology were discussed.The experimental results show that the microstructure,the number of CuAl2（θ phase） precipitates,and the dislocation density of the Al-4Cu-Mg alloy depend apparently on the process parameters.More segregation of Cu at the grain boundary happens with an increase of deformation temperature and a decrease of strain rate,leading to an increase in the number of θ phase.With an increase of height reduction,Cu segregation at the grain boundary decreases gradually.Moreover,unique dislocation morphologies including helical dislocations and dislocation loops appear at different process parameters and evolve to reduce the stored energy.

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