Segregation of Mg-6Gd alloy under natural convection:From macro solute distribution to micro dendrite growth  

作　　者：Hong-xu Chen Ang Zhang Hao Li Yu Gao Yu-hong Cui Guang-sheng Huang Bin Jiang Fu-sheng Pan 

机构地区：[1]National Engineering Research Center for Magnesium Alloys,National Key Laboratory of Advanced Casting Technologies,College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China

出　　处：《China Foundry》2024年第5期613-624,共12页中国铸造（英文版）

基　　金：supported by the National Key Research and Development Program of China(Grant No.2021YFB3701000);the National Natural Science Foundation of China(Grant Nos.52101125,52471118,U2037601,and U21A2048);the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(CAST)(Grant No.2022QNRC001).

摘　　要：Segregation is a serious defect in alloy ingots which severely deteriorates materials performance.The segregation defect in Mg-6Gd alloy is studied by coupling macro thermal-solutal-convection transport and micro dendrite growth.The macroscopic fluid dynamics and mass transfer equations are resolved to forecast the segregation behavior under conditions of continuous temperature variation during the solidification process.The numerical model is validated by testing double-diffusive natural convection in a closed square cavity.A phase field model is then applied to simulate the micro dendrite growth,using macro undercooling and liquid flow velocity as boundary conditions.Results show that the multiscale segregation behavior,including macro solute distribution and micro dendritic morphology,is strongly dependent on the temperature condition and the liquid convection,which provides guidance for reducing and eliminating the segregation defect.

关 键 词：magnesium alloy SEGREGATION numerical simulation phase-field simulation multiscale 

分 类 号：TG146.22[一般工业技术—材料科学与工程]