垂直Bridgman法生长CaF_2单晶传热过程的数值分析  

Numerical simulation of heat transfer by vertical Bridgman method of CaF_2 single crystals growth

作　　者：姚静[1,2] 周海[2] 卢一民[2] 万汉城[2] 

机构地区：[1]北京化工大学材料科学与工程学院,北京100029 [2]北京石油化工学院材料科学与工程学院,北京102617

出　　处：《材料科学与工艺》2015年第4期48-53,共6页Materials Science and Technology

摘　　要：采用有限元法对大尺寸氟化钙单晶的生长过程进行了传热分析,准稳态模型简化模拟计算过程.研究了梯度区不同的温度梯度对界面形状和晶体生长速度的影响,讨论了辐射传热对晶体生长过程传热的影响.研究表明:晶体生长过程中界面凸度发生变化;晶体生长速率与坩埚下降速率不一致;25 K/cm为合适的梯度区温度梯度;晶体内部辐射传热对单晶生长传热过程有重要影响.计算结果表明,3个时期的固相等温线的曲率小于液相的.根据数值模拟结果进行了晶体生长实验,生长出的晶体完整,透明,无宏观缺陷.Finite element method is used to simulate heat transfer during the growth process of large size calcium fluoride by the vertical Bridgman method,the calculation process was simplified by the quasi-steady state model. The effects of different temperature gradient in gradient zone on interface shape and crystal growth rate were investigated. The impact of radiation on heat transfer was discussed. Simulation results show that curvature of the solid isotherm is less than the curvature of the liquid isotherm at three different periods.Convexity of interface changed during crystal growth process. Rate of crystallization and descent velocity of crucible were inconsistent. 25 K / cm is suitable for temperature gradient of gradient zone. Radiation heat transfer inside the crystal has a major influence on the heat transfer of single crystal growth process. In light of simulation results,growth integrity,transparent crystals without macroscopic defects can be grown.

关 键 词：CAF2 有限元法 垂直Bridgman法 数值模拟 传热 温度场 

分 类 号：O78[理学—晶体学]