界面能各向异性对定向凝固枝晶生长的影响  

Effect of interface energy anisotropy on the dendritic growth in directional solidification

作　　者：张云鹏[1,2] 林鑫[1] 魏雷[1] 彭东剑[1] 王猛 黄卫东[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072 [2]北京航星机器制造有限公司,北京100013

出　　处：《物理学报》2013年第17期501-508,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:50971102;51271213);国家重点基础研究发展计划(973)(批准号:2011CB610402);高等学校学科创新引智计划(批准号:08040);高等学校博士学科点专项科研基金(批准号:20116102110016)资助的课题~~

摘　　要：采用元胞自动机(cellular automaton,CA)模型研究了界面能各向异性对二维定向凝固枝晶生长的影响.模拟结果显示当晶体的择优生长方向与热流方向一致时,随着界面能各向异性强度的增大,凝固组织形态由弱界面能各向异性时的海藻晶转变为强界面能各向异性时的树枝晶.同时,界面能各向异性强度会影响稳态枝晶尖端状态的选择,界面能各向异性越强,定向凝固稳态枝晶尖端半径越小,尖端界面前沿的液相浓度和过冷度越小.稳态枝晶生长的尖端状态选择参数与界面能各向异性强度也存在标度律的指数关系,而枝晶一次间距则受界面能各向异性强度影响较弱.当晶体的择优生长方向与热流方向呈40夹角时随着界面能各向异性强度的增大,凝固组织形态由海藻晶逐渐转变为退化枝晶,后又逐渐转变为倾斜枝晶.The dendritic growth patterns in directional solidification with different amplitudes of solid-liquid interface energy anisotropy were investigated using the two-dimensional cellular automata （CA） model. It is shown that when the preferred growth direction of the crystal was the same as the direction of thermal gradient, the solidification pattern would transform from seaweed to dendrite with the increase of amplitude of interface energy anisotropy. The amplitude of interface energy anisotropy could also influence the morphology of dendritic tips. As the amplitude of interface energy anisotropy increased, the dendritic tip radius, the liquid concentration ahead of the tip and the tip undercooling decreased. A power law relationship evisted between the stability parameter of dendritic tip and the amplitude of interface energy anisotropy in directional solidification. The primary arm spacing changed little with the increase of interface energy anisotropy. When the angle between the preferred growth direction of the crystals and the direction of thermal gradient was-40, and the amplitude of interface energy anisotropy increased, the solidification pattern would transform from seaweed to degenerated dendrite and finally to tilted dendrite.

关 键 词：元胞自动机 枝晶 界面能各向异性 

分 类 号：TG111.4[金属学及工艺—物理冶金]