预时效6201铝合金重复连续挤压组织与力学性能  

Microstructure and Mechanical Property of Pre-aged 6201 Aluminum Alloy Processed by R-Conform Process

作　　者：傅定发[1,2] 张文刚 胡加敏 滕杰[1,2] 张辉[1,2] FU Dingfa;ZHANG Wengang;HU Jiamin;TENG Jie;ZHANG Hui(College of Materials Science and Engineering,Hunan University,Changsha410082,China;Hunan Provincial Key Laboratory of Spray Deposition Technology and Application,Hunan University,Changsha410082,China)

机构地区：[1]湖南大学材料科学与工程学院,湖南长沙410082 [2]湖南大学湖南省喷射沉积技术应用重点实验室,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2018年第12期24-28,共5页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51671083)~~

摘　　要：利用电子背散射衍射、透射电子显微镜、X射线衍射仪、偏光金相显微镜和拉伸试验对连铸连轧6201铝合金经预时效及随后重复连续挤压过程中组织和性能进行研究.结果表明:6201铝合金的强塑积随着挤压道次的增加逐渐增加,从原始的2.93 GPa·%增加到第四道次的4.85 GPa·%,之后趋于平稳.预时效后合金析出了大量的β″相,随着重复连续挤压道次的增加,晶粒有效细化且组织变得更加均匀,晶粒平均尺寸从259μm细化至60μm;合金中高密度的位错逐渐缠结、塞积并向亚晶界转变,时效析出的针状β″相逐渐回溶到合金基体中.力学性能的变化是晶粒细化与均匀化、位错组态的变化以及弥散的β″相回溶的综合结果.The repetitive continuous extrusion forming process(R-Conform process)was carried out on the pre-aged6201Al alloy produced by continuous casting and rolling.The microstructure characteristic and mechanical property evolution of the R-Conform processed alloy were investigated using electron back-scatter diffraction(EBSD),transmission electron microscopy(TEM),X-ray diffractometer,polarizing metallographic microscopy,and tensile testing.The results show that R-Conform can effectively refine grain size and homogenize alloy microstructure.With the increase of R-Conform pass numbers,the balance of strength-ductility(TS×EL)increased from2.93GPa·%to4.85GPa·%after fourth passes,and then stabilized.A large number ofβ″phases precipitated in the pre-aged6201Al alloy after pre-aging.With the increase of R-Conform pass numbers,the grain was effectively refined and the homogenized alloy microstructure was formed,where the average size of the grain was refined from259μm to60μm.Meanwhile,high density of dislocations formed,gradually tangled with each other,and finally transformed to subgrain boundaries.A part of needleβ″phases dissolved into the Al alloy matrix.The evolution of the mechanical property was mainly attributed to the combined effect of grain refinement and homogenization,the synthetic effect of dislocation increase and the dissolution ofβ″phases.

关 键 词：6201铝合金 预时效 重复连续挤压 微观组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]