Annealing hardening effect aroused by solute segregation in gradient ultrafine-grained Mg-Gd-Zr alloy  

作　　者：Chunquan Liu Xianhua Chen Domonkos Tolnai Yaobo Hu Wei Zhang Yusheng Zhang Fusheng Pan 

机构地区：[1]College of Materials Science and Engineering,Chongqing University,Chongqing 400045,China [2]National Engineering Research Centre for Magnesium Alloys,Chongqing University,Chongqing 400045,China [3]Institute of Metallic Biomaterials,Helmholtz-Zentrum Hereon,Max-Planck Street 1,Geesthacht 21502,Germany [4]Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China

出　　处：《Journal of Materials Science & Technology》2023年第13期70-80,共11页材料科学技术（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos.52225101 and 52171103);the National Key R&D Program of China (No.2021YFB3701100);the Fundamental Research Funds for the Central Universities (No.2020CDJDPT001);the Natural Science Basic Research Plan in Shaanxi Province of China (No.2022JM-233);support from the Chinese Scholarship Council (CSC No.202106050087).

摘　　要：In this study,a remarkable annealing hardening effect was detected in gradient ultrafine-grained(UFG)Mg-0.32Gd-0.11Zr(at.%)alloy sheet fabricated by sliding friction treatment(SFT).Under the precipitation-free condition,the annealed UFG structure shows an obvious hardness increment from 1.40 GPa to 1.89 GPa after 200℃ heating for 12 h,which exhibits a much higher hardening response than the annealed coarse-grained(CG)structure.The high-angle annular dark-field scanning transmission elec-tron microscopy(HAADF-STEM)and elemental mapping reveal prominent segregation of solute Gd atoms along grain boundaries,which endows the UFG structure with excellent grain boundary stability.More-over,Gd segregation is also found around the extrinsic stacking fault(E-SFs)and the low-angle grain boundaries composed of edge dislocations.The large-scale solute partitioning provides a significant seg-regation hardening effect,which completely resists the softening effect aroused by the grain coarsening and dislocation annihilation.This work realizes a good combination of surface mechanical processing for fabricating UFGs and subsequent heat treatment,which earns desirable segregation hardening effects.

关 键 词：Ultrafine grains SEGREGATION Annealing hardening 

分 类 号：TG146.22[一般工业技术—材料科学与工程]