| The study work in this paper is part of the project "Processing the ultrathic and ultrawide constructions of A1 alloys with high quality"in the national "863"program.The aim is to provide A1 alloy with excellent combined properties to process Al profiles with complex section used in high speed trains by optimize composition of 6005 alloy.The effects of Mg,Si,Mn,Cu content on microstructures of as-cast alloys,mechanical properties and conductivity of the alloys after extrusion,solid solution by air and aging were studied.The main results obtained in this paper are followings:1)The overheating temperatures of 9 alloys in the orthogonal designation are less different,from 545? to 554?,so that the homogenization treatment is designed as 540?X8h.2)The effects of element Mg,Si,Cu and Mn on strength,elongation and conductivity of 6005 alloy were investigated by orthogonal designation.The intensity of effect on strength is Cu>Mn>Mg>Si,intensity of effect on elongation is Mg>Cu>Si>Mn,and intensity of effect on conductivity is Cu>Si>Mn>Mg.The selected composition of 6005 alloy is Al-0.53Mg-0.72Si-0.2Cu-0.28Mn-0.18Cr-0.05Ti?wt.%?by analysis of orthogonal designation.3)The properties of the alloy of selected composition after extrusion with solid solution by air and aging?T6?is that the tensile strength is 306.5MPa,yield strength is 279.1 MPa,elongation is 13.5%,hardness is 104HV,conductivity is 47.5%IACS.4)The properties of the alloy of selected composition after extrusion with solid solution by air and two rank aging is that the tensile strength is 313.7MPa,yield strength is 279.9MPa,elongation is 13.4%,hardness is 106HV,conductivity is 46%IACS.5)The content of Mn of selected alloy was expensed to optimize Mn content.Element Mn can refined the microstructure of the alloys.The combined properties is excellent at 0.20%Mn.When the content of Mn is over 0.20%the strength and elongation of the alloy decrease a little because of formation of thick Al6Mn particles. |
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