Microstructure inheriting evolution and strength-plasticity collaborative improvement mechanism of multidirectional rotary forged Al7075 sheets during T6 heat treatment  

作　　者：Xuan Hu Xinghui Han Lin Hua Jishi Zhang Jing Xu Fang Chai Wuhao Zhuang Fangyan Zheng 

机构地区：[1]Hubei Key Laboratory of Advanced Technology for Automotive Components,Wuhan University of Technology,Wuhan 430070,China [2]Hubei Longzhong Laboratory,Xiangyang 441000,China [3]School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China

出　　处：《Journal of Materials Science & Technology》2024年第36期14-38,共25页材料科学技术(英文版)

基　　金：supported by the National Natural Science Foundation of China(No.U21A20131);the Technical Development Project of COMAC Shanghai Aircraft Manufacturing Co.,Ltd.(No.COMAC-SFGS-2023-631);the 111 Project(No.B17034),andthe In-novative Research Team Development Program of Ministry of Edu-cation of China(No.IRT17R83).

摘　　要：Al7075 sheets are widely used in aerospace industry and their higher strength-plasticity collaborative improvement requirement is urgent.In this study,the microstructure inheriting the evolution and me-chanical properties of Al7075 sheets during multidirectional rotary forging(MRF)and T6 heat treatment are analyzed.The results show that the average grain size exhibits near-parabolic evolution with increas-ing MRF deformation amount.MRF20%+T6(20%MRF deformation amount+T6)condition possesses the largest grain size of 72.6μm,and its abnormal grain growth mechanism is that the medium deformation energy and high deformation heterogeneity in MRF20%deformed grains could cause asynchronous re-crystallization behavior during T6 heat treatment,and the grains with comparatively higher deformation energy get recrystallized firstly and devour adjacent grains along preferred011or223misorientation axis.MRF70%+T6 condition possesses the finest grain size of 14.2μm,and its fine grain inheriting mech-anism is that the uniformly high deformation energy in MRF70%deformed grains causes uniformly rapid recrystallization,and rapidly recrystallized grains effectively suppress grain boundary motion from adja-cent grains.With increasing MRF deformation amount,tensile strength and elongation values both exhibit near-antiparabolic evolution.MRF70%+T6 condition possesses the largest tensile strength(563 MPa)and elongation(17.73%),which increases by 8.27%and 80.55%compared to as-annealed+T6(MRF0%+T6)condition(tensile strength is 520 MPa and elongation is 9.82%),respectively.The strength-plasticity col-laborative improvement is mainly because the combination of effectively inherited fine grains,refined inclusion particles,and uniformly distributed fineη’particles after T6 heat treatment could promote smooth dislocation movement and coordinated slip behavior in most matrix grains,which contributes to the delay of stress localization and strength-plasticity collaborative improvement.

关 键 词：Al7075 sheets Multidirectional rotary forging T6 heat treatment Microstructure inheriting evolution Strength-plasticity collaborative improvement 

分 类 号：TG1[金属学及工艺—金属学]