脉冲电流作用下Pb-Al合金的液-固分相过程  

Liquid-Solid Phase Separation Process of Pb-Al Alloy Under the Effect of Electric Current Pulses

作　　者：李彦强 赵九洲[1,2] 江鸿翔[1,2] 张丽丽[1] 何杰[1,2] LI Yanqiang;ZHAO Jiuzhou;JIANG Hongxiang;ZHANG Lili;HE Jie(Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China)

机构地区：[1]中国科学院金属研究所师昌绪先进材料创新中心,沈阳110016 [2]中国科学技术大学材料科学与工程学院,沈阳110016

出　　处：《金属学报》2024年第12期1710-1720,共11页Acta Metallurgica Sinica

基　　金：国家重点研发计划项目No.2021YFA0716303;国家自然科学基金项目Nos.51971227、51974288和52174380;中国载人航天工程项目;中国载人航天工程空间应用系统项目No.KJZ-YY-NCL06;中国科学院科研仪器设备研制项目No.YJKYYQ20210012。

摘　　要：为了控制Pb-Al合金凝固过程、制备原位Al粒子弥散分布于Pb基体的高性能Pb-Al合金阳极材料,本工作开展了脉冲电流作用下Pb-Al液-固分相合金连续凝固实验,建立了脉冲电流下合金液-固分相过程的组织演变模型,并结合实验开展了模拟研究,分析了合金液-固分相过程及脉冲电流的影响机理。结果表明,脉冲电流能有效降低合金液-固分相过程中Al粒子的形核能垒,提升粒子形核率,促进弥散型原位Al粒子铅基复合凝固组织的形成;峰值电流密度j_(max)存在2个临界值j_(c1)、j_(c2):当j_(max)≤j_(c1)时,脉冲电流影响很弱;当j_(c1)<j_(max)<j_(c2)时,粒子形核率和数量密度随j_(max)增大快速升高;当j_(max)≥j_(c2)时,粒子形核率和数量密度随j_(max)增大继续升高,但升高速率较慢;电磁力导致Al粒子由试样表面向心部迁移,使合金形成由表面Pb壳和原位Al粒子铅基合金内核组成的壳/核型复合材料。The Pb-Al alloy,which undergoes liquid-solid(L-S)phase separation,can potentially serve as a high-performance and low-cost anode material for hydrometallurgy and a grid material for lead-acid batteries.For this purpose,a microstructure containing uniformly dispersed micro/nano Al-rich particles in the Pb matrix is desired.However,during cooling of the Pb-Al alloy melt,Al-rich particles nucleate from the matrix melt first,grow,and migrate in the melt until they are caught by the solidification interface.Consequently,Pb-Al alloys often exhibit a solidification microstructure with coarse Al-rich parti-cles or significant phase segregation.Recent studies have shown that the application of electric current pulses(ECPs)during solidification can effectively modify the microstructure evolution.This research aims to investigate the possibility of controlling the L-S phase separation process and microstructure of Pb-Al alloys.To achieve this,continuous solidification experiments were carried out on Pb-Al L-S phase separation alloy while subject to ECPs.A theoretical model describing the microstructure formation during the L-S phase separation process of the alloy under the effect of ECPs was proposed.The microstructure evolution was simulated according to the experimental conditions,and the effect of ECPs on the L-S phase separation process of the alloy was analyzed.It was demonstrated that ECPs can effectively reduce the energy barrier for the nucleation of Al-rich particles during the L-S phase separation process of Pb-Al alloy,enhance the particlesnucleation rate,and reduce the average radius,thereby promoting the formation of a composite containing in situ micro/nano Al-rich particles embedded in the Pb matrix.The peak current density(j_(max))has two critical values(j_(c1) and j_(c2)).When j_(max)≤j_(c1),ECPs have a negligible effect on the nucleation behavior of Al-rich particles.When j_(c1)<j_(max)<j_(c2),the nucleation rate and number density of the Al-rich particles increase rapidly with increasing j_(max).When j

关 键 词：脉冲电流 偏晶合金 液-固分相 形核 模拟 

分 类 号：TG111.4[金属学及工艺—物理冶金]