Morphological evolution of the solid-liquid interface near grain boundaries during directional solidification  

作　　者：XING Hui WANG CaiFang WANG JianYuan CHEN ChangLe 

机构地区：[1]Shanxi Key Laboratory for Condensed Matter Structure and Properties, Northwestern Polytechnical University, Xi＇an 710072, China [2]Department of Mathematics, Shanghai Maritime University, Shanghai 201306, China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2011年第12期2174-2180,共7页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos.61078057 and 51172183);NPU Foundation for Fundamental Research (Grant Nos.NPU-FFR-JC201048 and JC201155);the Science & Technology Program of Shanghai Maritime University (Grant No.20110054);the Project of the Excellent Youth of Shanghai (WANG CaiFang)

摘　　要：Morphological evolution of the solid-liquid interface near grain boundaries has been studied during directional solidification of succinonitrile-based transparent alloys (SCN-0.9wt%DCB). Experimental results show that the grain boundary provides the starting point of morphological instability of the solid-liquid interface. The initial perturbation near the grain boundary is significantly larger than other perturbations on the interface. The initial shape of the interface and the competition between the thermal direction and preferred crystalline orientations determine the subsequent growth pattern selections. The temporal variations of the curvature radius of cell/ridge tips near the grain boundary have also been studied when the instability occurs. This process is divided into three parts. As the pulling velocity increases, dendrites at the grain boundary grow in two different directions to form a bicrystal microstructure. Side branches on either side of the dendrite exhibit different growth patterns.Morphological evolution of the solid-liquid interface near grain boundaries has been studied during directional solidification of succinonitrile-based transparent alloys （SCN-0.9wt%DCB）. Experimental results show that the grain boundary provides the starting point of morphological instability of the solid-liquid interface. The initial perturbation near the grain boundary is significantly larger than other perturbations on the interface. The initial shape of the interface and the competition between the thermal direction and preferred crystalline orientations determine the subsequent growth pattern selections. The temporal variations of the curvature radius of cell/ridge tips near the grain boundary have also been studied when the instability occurs. This process is divided into three parts. As the pulling velocity increases, dendrites at the grain boundary grow in two different directions to form a bicrystal microstructure. Side branches on either side of the dendrite exhibit different growth patterns.

关 键 词：grain boundary solid-liquid interface directional solidification growth directions 

分 类 号：TQ174.758[化学工程—陶瓷工业] TN213[化学工程—硅酸盐工业]