固溶工艺对7055铝合金组织和性能的影响  

Effect of solid solution process on microstructure and properties of 7055 aluminum alloy

作　　者：张兆刚 张存生[1] 赵国群[1] 陈良[1] 马新武[1] ZHANG Zhaogang;ZHANG Cunsheng;ZHAO Guoqun;CHEN Liang;MA Xinwu(Key Laboratory for Liquid-Solid Structural Evolution&Processing of Materials(Ministry of Education),Shandong University,Jinan 250061,China)

机构地区：[1]山东大学材料液固结构演变与加工教育部重点实验室,山东济南250061

出　　处：《中南大学学报（自然科学版）》2021年第9期3143-3152,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51975330);山东省重大创新工程项目(2019JZZY010360)。

摘　　要：在热挤压过程中,较低成形温度和较慢挤压速度导致7055铝合金在挤出后达不到良好的固溶效果。为了充分发挥高强合金的性能优势,需要进行离线固溶处理。首先,通过扫描电子显微镜(SEM)、能谱仪(EDS)和电子背散射衍射(EBSD)等测试技术,研究不同单级固溶制度下7055高强铝合金螺旋面型材的第二相分布、晶粒取向及形貌;其次,通过显微硬度测试和拉伸实验,探究固溶制度对其力学性能的影响规律;最后,通过电化学腐蚀等测试,研究固溶制度对其耐腐蚀性能的影响规律。研究结果表明:随着固溶温度升高,原均质态和挤压态合金中的第二相逐渐溶解,并伴随着晶粒的粗化以及等轴状再结晶晶粒生长;而470℃下,随着固溶时间延长,部分相溶解,再结晶程度提高;合金的抗腐蚀性能随固溶温度升高及固溶时间延长均呈现先升高后降低的规律。470℃/60 min下,合金取得了最优的力学性能,维氏硬度为210.5,抗拉强度为683 MPa,屈服强度为637 MPa,伸长率为15.0%,自腐蚀电位为−0.7371 V,自腐蚀电流密度为6.41×10^(−7) A/cm^(2)。In the hot extrusion process of 7055 aluminum alloy,lower forming temperature and slower extrusion speed led to the poor solid solution effect after extrusion.In order to take full advantage of the properties of high strength alloys,off-line solution treatment was required.Firstly,by scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and electron backscattering diffraction(EBSD),the second phase distribution,grain orientation and morphology of 7055 high-strength aluminum alloy helical profile in different single-stage solution systems were studied.Secondly,through microhardness test and tensile test,the influence of solution systems on its mechanical properties was explored.Finally,the effect of solution systems on its corrosion resistance was studied by electrochemical corrosion test.The results show that with the increase of solution temperature,the second phase in the original homogeneous and extruded alloys dissolves gradually.At the same time,the grains become coarser and the equiaxed recrystallized grains grow.With the prolongation of solution time at 470℃,the partial phase dissolves and the degree of recrystallization increases.The corrosion resistance of the alloy increases firstly and then decreases with the increase of solution temperature and time.At 470℃/60 min,the optimal mechanical properties of the alloy are obtained,with the Vickers hardness of 210.5,the tensile strength of 683 MPa,the yield strength of 637 MPa,and the elongation of 15.0%.The self-corrosion potential is-0.7371 V,and the self-corrosion current density is 6.41×10^(-7) A/cm^(2).

关 键 词：高强铝合金 型材挤压 固溶处理 力学性能 电化学腐蚀 

分 类 号：TG379[金属学及工艺—金属压力加工]