Improving strength-ductility of Mg-8.5Gd-4.5Y-0.8Zn-0.4Zr magnesium alloy due to bimodal LPSO and dislocations  

作　　者：Xiaohua Zhang Yuan Shi Jiaqi Li Hongyan Yue Chao Li Siming Guo Qiang Chen 

机构地区：[1]School of Materials Science and Chemical Engineering,Harbin University of Science and Technology,Harbin,150040,China [2]School of Binary Graduate,Binary University of Management&Entrepreneurship,Puchong,47100,Malaysia [3]Southwest Technology and Engineering Research Institute,Chongqing,400039,China

出　　处：《Journal of Rare Earths》2025年第4期832-842,I0007,共12页稀土学报(英文版)

基　　金：supported by the Key Research and Development Program of Heilongjiang (2022ZX01A01);National Natural Science Foundation of China (51975167);Natural Science Foundation of Heilongjiang Province(LH2022E080)。

摘　　要：Rare-earth(RE) magnesium alloys have attracted lots of attention due to their excellent mechanical properties.In this work,the microstructure and mechanical properties of as-extruded 8.5Gd-4.5Y-0.8Zn-0.4Zr magnesium alloy under different solution treatment were examined with the optical microscope(OM),scanning electron microscope(SEM),high resolution transmission electron microscope(HRTEM),electron back-scattered diffraction(EBSD) and Instron testing machine.The results show that the ES12alloy(solution treatment for 12 h at 520℃) has the highest ultimate tensile strength(UTS) of 390 MPa with a fracture elongation of 24.5% at the co st of a minor drop in yielding strength(YS) compared to the asextruded alloy.During solution treatment,the block-shaped long period stacking ordered(LPSO) in asextruded alloy evolves into plate-shaped LPSO,which disperses at grain boundaries(GBs),and lamellar LPSO,which distributes in grains.The coexistence of plate-shaped and lamellar LPSO,which impedes the dislocations movement,and the activated dislocations are regarded as the primary reasons for mechanical properties improvement.Furthermore,the(11-21) <1-100> texture in as-extruded alloy transforms into the(11-20) <0001> texture in ES12 alloy.The average grain size increases from 3.45 μm in as-extruded alloy to 18.70 μm in ES12 alloy.The Schmid factors of {0001} <11-20>,{10-10} <11-20>,{10-11} <11-20>,and {11-22} <11-23> increase,which indicate that slip systems are more easily activated in plastic deformation.The dynamic recrystallization(DRX) grains fraction increase to 92.8% for ES12 alloy due to the particle-stimulated nucleation(PSN) mechanism triggered by block-shaped and plate-shaped LPSO.The freshly DRXed grains further weaken the texture,and reduce the dislocation density.All of these factors increase elongation of RE magnesium alloy.

关 键 词：Rare earths Magnesium alloy Solution treatment LPSO TEXTURE Mechanical properties 

分 类 号：TG146.22[一般工业技术—材料科学与工程]