预变形对2050铝锂合金晶粒细化及超塑性的影响  

Effects of pre-deformation on grain refinement and superplasticity of 2050 Al-Li alloy

作　　者：叶凌英[1,2,3] 孙泉 李红萍 刘胜胆[1,2,3] 张新明 YE Ling-ying;SUN Quan;LI Hong-ping;LIU Sheng-dan;ZHANG Xin-ming(School of Materials Science and Engineering,Central South University,Changsha 410083,China;Key Laboratory of Nonferrous Metal Materials Science and Engineering(Ministry of Education),Central South University,Changsha 410083,China;Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,Central South University,Changsha 410083,China)

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]中南大学有色金属材料科学与工程教育部重点实验室,长沙410083 [3]中南大学有色金属先进结构材料与制造协同创新中心,长沙410083

出　　处：《材料工程》2019年第12期92-97,共6页Journal of Materials Engineering

基　　金：国家重点研发计划项目(2017YFB0306300)

摘　　要：通过形变热处理工艺制备2050铝锂合金细晶板材,采用光学显微镜、扫描电镜等研究预变形对第二相分布、晶粒组织及板材超塑性的影响。结果表明:采用预变形后,高温过时效过程中板材晶内形成大量亚晶,大量的亚晶界促进了T B相的析出同时提高了粗化速率,显著增加了晶内T B相的尺寸,使得有效激发再结晶形核第二相粒子体积分数由0.92%提高至3.28%。同时与未预变形板材相比,板材中心层平均晶粒尺寸由12.59μm降低至9.59μm,表层平均晶粒尺寸由10.79μm降低至8.60μm,晶粒细化效果得到明显改善,超塑性变形能力显著提升,在490℃,2×10^-4 s^-1的变形条件下,伸长率由230%提高至470%。Fine-grain 2050 Al-Li alloy sheets were prepared by thermomechanical treatment processing(TMTP).The effects of pre-deformation on second phase distribution,grain structure and superpl-asticity of alloy sheets were studied by optical microscope and scanning electron microscope.The results show that after pre-deformation,a large amount of subgrains are formed in the plate during high temperature overaging.A large number of subgrain boundaries promote the precipitation of T B phase and increase the roughening rate,which significantly increases the size of intragranular T B phase.The volume fraction of second phase particles that effectively stimulates recrystallization nucleation increases from 0.92%to 3.28%.Compared with the non-predeformed sheets,the average grain size of the center layer of the sheets is reduced from 12.59μm to 9.59μm,the average grain size of the surface layer is reduced from 10.79μm to 8.60μm,the grain refinement effect is obviously improved,the superplastic deformation ability is significantly improved.The elongation of superpla-stic deformation increases from 230%to 470%under the condition of 490℃and 2×10^-4 s^-1.

关 键 词：2050铝锂合金 晶粒细化 形变热处理 粒子激发形核 超塑性 

分 类 号：TG146.2[一般工业技术—材料科学与工程]