Achieving superior strength-ductility balance in novel heterogeneous lamella structures of Al-Zn-Mg-Cu alloys  

作　　者：Haitao Jiang Hui Xing Zihan Xu Jing Feng Jiao Zhang Baode Sun 

机构地区：[1]Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming,Shanghai Jiao Tong University,Shanghai 200240,China [2]State Key Lab of Metal Matrix Composites,Shanghai Jiao Tong University,Shanghai 200240,China [3]Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration,Shanghai Jiao Tong University,Shanghai 200240,China

出　　处：《Journal of Materials Science & Technology》2024年第17期122-135,共14页材料科学技术（英文版）

基　　金：supported by the National Key Research and Development Program of China(No.2023YFB3406800);the National Natural Science Foundation of China(Nos.52271036 and 51971237).

摘　　要：Heterogeneous structures(HS)materials have the potential to exhibit simultaneous improvement in strength and plasticity due to hetero-deformation-induced hardening(HDI)between multiple grain struc-tures.However,achieving HS in aluminum alloy can be quite challenging.In this study,7000 series alu-minum alloys are investigated by incorporating rare earth element Y to develop a dual-phase structure containing Al_(8)Cu_(4)Y and Al_(3)(Y,Zr)phases.And a heterogeneous lamella structure(HLS)is formed through the synergistic effect of Al_(8)Cu_(4)Y which includes dynamic recrystallization nucleation during deformation,and Al_(3)(Y,Zr)which hinders the growth of recrystallized grain by means of pinning dislocations and sub-grain boundaries.Substructures such as precipitates and nanocrystals are incorporated during the fabri-cation of HS,allowing for precise control over the volume fraction of fine grains by adjusting the ratio of two-scale second phases.When Y content reaches 0.3%,the 7Y55-2/heterogeneous lamella structure(HLS)samples exhibit a fine grain volume fraction of 76.5 vol.%,a tensile strength of 695 MPa,and an elon-gation of 16.6%.The alloy contains a large number of dislocations that preferentially induce the growth ofη’phases along specific directions,thereby promoting their development.The multi-coupling effect and composite strengthening mechanisms in the“heterostructure-dislocation-precipitate”microstructure contribute to the intrinsic excellent strength and plasticity of the alloy.This study tackles the challenge of inverted strength and plasticity observed in Al-Zn-Mg-Cu-Zr alloys,offering novel insights that pave the way for further applications of heterogeneous materials.

关 键 词：Al-Zn-Mg-Cu-Zr-Y alloy Heterogeneous lamella structures Properties HDI hardening Deformation mechanism 

分 类 号：TG139[一般工业技术—材料科学与工程]