铝液凝固过程中显微组织对溶质元素偏析的影响  

Effect of Microstructure on Solute Element Segregation during Solidification of Liquid Aluminum

作　　者：秦颐鸣 吴镇宇 黄科林 冯恩浪 陆泰榕 李永弟 QIN Yiming;WU Zhenyu;HUANG Kelin;FENG Enlang;LU Tairong;LI Yongdi(Institute of Functional Material Co.,Ltd.,Guangxi Institute of Industrial Technology,Nanning 530000,China;Guangxi Key Laboratory of Green Manufacturing for Ecological Aluminum Industry,Baise 533000,Guangxi,China;Geely Baikuang Group Co.,Ltd.,Baise 533000,Guangxi,China;Guangxi Xinya Material Co.,Ltd.,Nanning 530000,China)

机构地区：[1]广西产研院新型功能材料研究所有限公司,南宁530000 [2]广西生态铝绿色制造重点实验室,广西百色533000 [3]吉利百矿集团有限公司,广西百色533000 [4]广西新雅复合材料有限公司,南宁530000

出　　处：《有色金属（冶炼部分）》2023年第11期79-85,共7页Nonferrous Metals（Extractive Metallurgy)

基　　金：广西壮族自治区产业技术研究院资助项目(20221021);广西重点研发计划项目(桂科AB21220028)。

摘　　要：以溶质元素分配系数小于1的元素Fe、Si、Ga、Zn为研究对象,通过分析工业试验条件下铝液凝固过程中杂质元素含量变化,以及对应的显微组织(包括晶粒形貌、尺寸和金属间化合物),并与热力学计算软件Factsage计算的Scheil-Gulliver冷却条件下杂质元素含量和析出相进行了比较。研究发现,铝液凝固初期固相中杂质元素含量最低,且均大于理论计算值,随着凝固的进行,杂质元素含量逐渐增高且与理论值偏差越来越大,出现以上现象的原因包括:1)铝液实际凝固过程中存在边界层效应,即从固相中排出的杂质元素没有完全扩散到液相中;2)铝液实际凝固过程中存在微观偏析现象,即沿着晶界处有Al-Fe-Si中间相析出。另外,发现本研究试验条件下铝液凝固组织有粗大柱状晶、细小柱状晶、等轴晶,粗大的柱状晶更有利于提高部分杂质元素的偏析提纯效率,通过控制提高强制冷却可以促进粗大柱状晶的形成。Taking Fe,Si,Ga and Zn,whose solute element partition coefficient is less than 1,as the research object,the change of impurity element content during solidification of liquid aluminum under industrial test conditions and the corresponding microstructure(including grain morphology,size and intermetallic compounds)were analyzed.The contents of impurity elements and precipitated phase under Scheil-Gulliver cooling condition calculated by thermodynamic software Factsage were compared.It is found that the content of impurity elements in the solid phase of liquid aluminum is the lowest at the initial solidification stage,and all of them are greater than the theoretical calculated value.With the progress of solidification,the content of impurity elements gradually increases and the deviation from the theoretical value becomes larger and larger.The reasons for the above phenomena include:1)the boundary layer effect exists in the actual solidification process of liquid aluminum,that is,the impurity elements discharged from the solid phase are not fully diffused into the liquid phase;2)there is microscopic segregation in the actual solidification process of liquid aluminum,that is,Al-Fe-Si intermediate phase precipitates along the grain boundary.In addition,under the experimental conditions of this study,it is found that the solidification structure includes coarse columnar crystals,fine columnar crystals and equiaxed crystals.The coarse columnar crystals are more beneficial to promote the segregation and purification efficiency of some impurity elements,and the formation of coarse columnar crystals can be promoted by controlling and increasing the cooling intensity.

关 键 词：偏析 高纯铝 显微组织 杂质元素 凝固 

分 类 号：TG146.21[一般工业技术—材料科学与工程]