Al-20%Cu多晶粒竞争生长的原位观测及汇聚型枝晶淘汰模型构建  

In situ observation of multi-grain competitive growth in Al−20wt.%Cu and establishment of converging-case dendrite elimination model

作　　者：李发国 周莲 谢玉 张佼[3] Mike DODGE 尹付成 孙宝德[3] Fa-guo LI;Lian ZHOU;Yu XIE;Jiao ZHANG;Mike DODGE;Fu-cheng YIN;Bao-de SUN(Key Laboratory of Materials Design and Preparation Technology of Hunan Province,School of Materials Science and Engineering,Xiangtan University,Xiangtan 411105,China;Central Research Institute,Baoshan Iron&Steel Co.,Ltd.,Shanghai 201900,China;School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;TWI Ltd,Granta Park,Great Abington,Cambridge CB216AL,UK)

机构地区：[1]湘潭大学材料科学与工程学院湖南省材料设计与制备技术重点实验室,湘潭411105 [2]宝山钢铁有限公司中央研究院,上海201900 [3]上海交通大学材料科学与工程学院,上海200240 [4]TWI Ltd,Granta Park,Great Abington,Cambridge CB216AL,UK

出　　处：《Transactions of Nonferrous Metals Society of China》2024年第7期2095-2107,共13页中国有色金属学报（英文版）

基　　金：supported by the Natural Science Foundation of Hunan Province,China(No.2021JJ30672);the Science and Technology Project of Education Department of Hunan Province,China(No.22A0100);the National Natural Science Foundation of China(No.51627802);Xiangtan University Scientific Research Start-up Fund。

摘　　要：采用同步辐射成像技术研究Al-20%Cu(质量分数)亚共晶合金的晶粒竞争生长动力学,并建立与实验结果相一致的数学模型。结果表明,对于发散型竞争生长,遵循“正常淘汰”规则。对于汇聚型竞争生长,成分过冷的作用加速非择优取向晶粒中一次枝晶臂的生长速度,导致非择优取向枝晶出现“异常淘汰”现象,淘汰择优取向枝晶。探讨汇聚型竞争生长的“正常淘汰”与“异常淘汰”之间的临界条件,建立枝晶生长速率、枝晶臂间距和枝晶倾斜角之间的数学关系,又称“二次枝晶臂阻挡模型”,可以快速预测晶界位相和淘汰类型。Synchrotron radiography was performed during the solidification of Al−20wt.%Cu hypoeutectic alloy to study the competitive grain growth dynamics and a mathematical model consistent with the experimental results was established.The experimental results showed that for the diverging competitive growth,the“normal elimination”rule played a role.For converging competitive growth,the growth rate of the primary dendrite arms in the non-preferentially oriented grains was accelerated due to constitutional supercooling,resulting in the phenomenon of“abnormal elimination”in which the non-preferentially oriented dendrites would eliminate the preferentially oriented dendrites.The critical conditions between“normal elimination”and“abnormal elimination”of converging competitive growth were explored using a mathematical model.The mathematical model named the“secondary dendrite arm blocking model”among dendrite growth rate,dendrite arm spacing and dendrite inclination angle was established,which could quickly predict the orientation of grain boundaries and the type of elimination.

关 键 词：竞争生长 同步辐射成像 定向凝固 数学模型 AL-CU合金 

分 类 号：TG146.21[一般工业技术—材料科学与工程]