Variation of mechanical properties and microstructure of hot-rolled AA2099 Al-Li alloy induced by the precipitation during preheating process  

作　　者：Fei Guo Weijiu Huang Xusheng Yang Haipeng Dong Hang Yu Qiuyu Chen Li Hu Luyao Jiang 

机构地区：[1]College of Materials Science and Engineering,Chongqing University of Technology,Chongqing 400054,China [2]College of Materials Science and Engineering,Chongqing University of Arts and Science,Chongqing 402160,China [3]Chongqing Materials Research Institute Co.,Ltd,Chongqing 400707,China

出　　处：《Journal of Materials Science & Technology》2022年第15期198-209,共12页材料科学技术（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Grant No. 51871038);the Chongqing Key Project of Technology Innovation and Application Development (Grant No. cstc2019jscx-mbdx X0025);the support from the University Innovation Research Group of Chongqing (Grant No. CXQT20023)。

摘　　要：Preheating is the first step for thermal-mechanical processing of the materials. Several preheating schedules were designed based on industrial manufacturing to explore their effect on the microstructure and mechanical properties of AA2099 Al-Li alloy during the following hot rolling. The results show that the mechanical properties of as-rolled sheets are quite sensitive to preheating. Various types of secondary phases, including δ', T1 and T2 phases, were precipitated during the heating process. The difference among precipitates is the main reason to induce the variation of mechanical properties for as-rolled sheets. A rapid heating rate gave rise to the precipitation of δ' phase, which largely promoted yield stress and ultimate tensile strength in as-rolled sheets. T1 phase was more favorable in the preheating with a holding period at 150–250 °C, which caused a moderated strain hardening behavior. Precipitates formed during preheating induced different slip behaviors in the following deformation. The coexistence of T1 and δ' phase could restrict planar slip, which inhibited the formation of the shear band. The difference in the activity of non-octahedral slips and planar slips determined the strain hardening effect, which should be the reason for the variation of mechanical properties of as-rolled sheets.

关 键 词：Aluminum-lithium alloys PREHEATING PRECIPITATION Mechanical properties Shear band 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG335.11[金属学及工艺—金属材料]