Influence of pre-stretching on the tensile strength,fatigue properties and the in-plane anisotropy in Al-Cu-Li alloy AA2099

作     者：Xianghui Zhu Xusheng Yang Weijiu Huang Weiyi Qiu Xin Wang Fei Guo Li Hu Miao Gong Xianghui Zhu;Xusheng Yang;Weijiu Huang;Weiyi Qiu;Xin Wang;Fei Guo;Li Hu;Miao Gong

作者机构：College of Materials Science and EngineeringKunming University of Science and TechnologyKunming 650093China College of Materials Science and EngineeringChongqing University of Arts and SciencesChongqing 402160China College of Materials Science and EngineeringChongqing University of TechnologyChongqing 400044China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2023年第145卷第14期

页      面：249-259页

核心收录：

学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：This work is financially supported by the National Science Foun-dation of China(No.51871038) the Basic Research and Frontier Exploration Project of Chongqing Science and Technology Com-mission(No.cstc2021ycjh-bgzxm0173) the Basic Research and Frontier Exploration Project of Chongqing Science and Technology Commission(No.cstc2021ycjh-bgzxm0175)。 

主　　题：Aluminum-lithium alloys Precipitation Mechanical properties Fatigue crack propagation 

摘      要：The influence of pre-stretching prior to artificial aging on microstructure,tensile properties,and fatigue behavior of AA2099-T8 sheets was investigated.The results showed that increased pre-strain level from 1%to 6%resulted in a more uniform distribution and increasing density of the T_(1)phase.The localized plastic deformation during pre-stretching led to the formation of dense precipitation bands(DPBs)and precipitation free bands(T_(1)-PFBs)in the sheets with the 1%pre-strain.The non-uniform distribution of the T_(1)phase with T_(1)-PFBs and DPBs resulted in a decrement in elongation and a strong in-plane anisotropy of tensile properties.An appropriate level of pre-strain should be executed aiming to improve elongation and reduce the tensile anisotropy by promoting a uniform distribution of the T_(1)phase.In-plane anisotropy of yield strength due to the presence of DPBs and T_(1)-PFBs was quantitatively analyzed by the modified Hall-Petch formula.The results of the calculation for the modified model showed good agreement with the experiment.In addition,resistances of fatigue crack propagation(FCP)in the same orientation were gradually decreased with the increment of pre-strain due to the increment in yield strength and more uniform distribution of the T_(1)phase.For the in-plane anisotropy of FCP resistance,the main reasons were the development of rough fracture surfaces and the transgranular fracture modes in L-T orientation.