“Branched”structural transformation of the L1_(2)-Al_(3)Zr phase manipulated by Cu substitution/segregation in the Al-Cu-Zr alloy system  

作　　者：Lipeng Ding Mingqi Zhao Flemming J.H.Ehlers Zhihong Jia Zezhong Zhang Yaoyao Weng Dominique Schryvers Qing Liu Hosni Idrissi 

机构地区：[1]Key laboratory for Light-weight Materials,Nanjing Tech University,Nanjing 211816,China [2]School of Automation,Chongqing University of Posts and Telecommunications,Chongqing 400065,China [3]Department of Physics,Electron Microscopy for Materials Science(EMAT),University of Antwerp,Groenenborgerlaan 171,B-2020,Belgium [4]Department of Materials,University of Oxford,Oxford 1OX3PH,UK [5]School of Materials Science and Engineering,Nanjing Institute of Technology,Nanjing 211167,China [6]Institute of Mechanics,Materials and Civil Engineering,UCLouvain,IMAP,1348 Louvain-la-Neuve,Belgium

出　　处：《Journal of Materials Science & Technology》2024年第18期186-206,共21页材料科学技术（英文版）

基　　金：supported by the National Key Research and Development Program(No.2020YFA0405900);the National Natural Science Foundation of China(Grant No.52371111 and U2141215);the Natural Science Foundation of Jiangsu Province(No.BE2022159).

摘　　要：The effect of Cu on the evolution of the Al_(3)Zr phase in an Al-Cu-Zr cast alloy during solution treatment at 500℃has been thoroughly studied by combining atomic resolution high-angle annular dark-field scanning transmission electron microscopy,energy-dispersive X-ray spectroscopy and first-principles cal-culations.The heat treatment initially produces a pure L1_(2)-Al_(3)Zr microstructure,allowing for about 13%Cu to be incorporated in the dispersoid.Cu incorporation increases the energy barrier for anti-phase boundary(APB)activation,thus stabilizing the L1_(2)structure.Additional heating leads to a Cu-induced“branched”path for the L1_(2)structural transformation,with the latter process accelerated once the first APB has been created.Cu atoms may either(i)be repelled by the APBs,promoting the transformation to a Cu-poor D0_(23) phase,or(ii)they may segregate at one Al-Zr layer adjacent to the APB,promoting a transformation to a new thermodynamically favored phase,Al4 CuZr,formed when these segregation layers are periodically arranged.Theoretical studies suggest that the branching of the L1_(2)transformation path is linked to the speed at which an APB is created,with Cu attraction triggered by a comparatively slow process.This unexpected transformation behavior of the L1_(2)-Al_(3)Zr phase opens a new path to un-derstanding,and potentially regulating the Al_(3)Zr dispersoid evolution for high temperature applications.

关 键 词：Aluminum alloys TRIALUMINIDES Anti-phase boundary High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) First-principles calculations 

分 类 号：TG335.12[金属学及工艺—金属压力加工] TG146.414[一般工业技术—材料科学与工程]