静电悬浮深过冷熔融锆形核凝固测量  

Nucleation and solidification measurement of deep-undercooling molten zirconium under electrostatic levitation

作　　者：陆潇晓 张明辉[3] 刘晓珂 王艳秋 郑福 孙志斌 LU Xiao-xiao;ZHANG Ming-hui;LIU Xiao-ke;WANG Yan-Qiu;ZHENG Fu;SUN Zhi-bin(National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China;School of Computer Science and Technology,University of Chinese Academy of Sciences,Beijing 100049,China;Shanghai Institute of Ceramics,Chinese Academy of Sciences,Shanghai 200050,China)

机构地区：[1]中国科学院国家空间科学中心,北京100190 [2]中国科学院大学计算机科学与技术学院,北京100049 [3]中国科学院上海硅酸盐研究所,上海200050

出　　处：《中国有色金属学报》2023年第3期804-816,共13页The Chinese Journal of Nonferrous Metals

基　　金：中国科学院科研仪器设备研制项目(YJKYYQ20190008);中国科学院空间科学战略先导专项(XDA15013600);中国科学院青年创新促进会优秀会员项目(2013105,Y201728);国家自然科学基金资助项目(61474123,61274024)。

摘　　要：采用静电悬浮无容器实验技术,对纯度99.6%Zr样品的深过冷程度和形核凝固机制进行了系统研究。结果表明:样品的临界过冷度为363.9 K(0.17T_(m)),熔点时的液态比热容为42.42 J/(mol·K),凝固前降温速率与过冷度的变化规律为ΔT=-1.792R_(c)+664.15。通过超高速摄像方法,测得样品的枝晶生长速度与过冷度呈幂函数关系,在过冷度300 K处,枝晶生长速度达到34.6 m/s。通过对上述实验数据进行基于经典成核理论的统计分析,计算得到样品在最大概率过冷度300K处(0.14Tm)的成核活化能为52.19kBT,吉布斯自由能差为1.503×108J/m^(3),固液界面能为0.121 J/m^(2)。对比发现:随着锆含量的降低,样品的最大概率过冷度、成核活化能、吉布斯自由能差和固液界面能都明显减小。The undercooling degree and nucleation solidification mechanism of zirconium samples with 99.6%purity were systematically investigated by electrostatic levitation containerless method.The experimental results show that hypercooling limit of the sample is 363.9 K(0.17Tm),the liquid specific heat capacity value at melting point is 42.42 J/(mol·K),and the variation law of cooling rate before solidification and undercooling isΔT=−1.792R_(c)+664.15.Through the ultra-high speed camera method,the dendrite growth rate of the sample has a power function relationship with the undercooling.At the undercooling of 300 K(0.14Tm),the dendrite growth rate reaches 34.6 m/s.Through the statistical analysis of the above experimental data based on the classical nucleation theory,it is calculated that the activation energy of nucleation at the maximum probability undercooling of 300 K is 52.19kBT.The Gibbs free energy difference and the solid-liquid interface energy are determined to be 1.503×108 J/m^(3) and 0.121 J/m^(2),respectively.It is found that,with slight decrease of zirconium content,the maximum probability undercooling,nucleation activation energy,Gibbs free energy difference and solid-liquid interface energy become smaller significantly.

关 键 词：液态锆 静电悬浮 深过冷 枝晶生长 形核 

分 类 号：TG146.4[一般工业技术—材料科学与工程]