试样厚度对共晶组织形态的影响  

INFLUENCE OF SAMPLE THICKNESS ON THE MORPHOLOGY OF EUTECTIC SYSTEM

作　　者：孟广慧[1] 林鑫[1] 杜立成[1] 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

出　　处：《金属学报》2007年第5期459-464,共6页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目50201012和50471065资助

摘　　要：采用透明模型合金CBr4-11．7％C2Cl6(摩尔分数),对共晶合金定向凝固界面演化进行了实时观察,研究了初始非稳态凝固过程中试样厚度对于共晶合金界面能各向异性效应及层片间距调整机制的影响规律．结果表明,共晶界面能各向异性效应和层片调节机制与试样厚度显著相关．试样厚度大于48μm时,试样厚度对界面能各向异性的影响可以忽略;当试样厚度为48μm或更小时,界面能各向异性的效应开始显现,由于初始晶粒的取向不同,部分层片偏离温度梯度方向生长;当试样厚度为16μm时,层片间距的调整由初始的多层调节机制转变为准二维调节机制．In situ observation on eutectic morphological evolution was carried out during directional solidification of transparent organic alloy CBr4-11.7%C2Cl6 （mole fraction）. The influences of sample thickness on the anisotropy effect of interface energy and the adjustment mechanism of lamellar spacing in the initial transient of eutectic solidification were investigated. It is found that the anisotropy effect and the adjustment mechanism depend on the sample thickness remarkably. The anisotropy effect can be ignored when the thickness is larger than 48 μm. When the thickness is less than 48 μm, the anisotropy effect became distinct, which makes the growth direction of some eutectic lamellae deviated away from the direction of temperature gradient due to the orientation difference of prior grains. When the thickness reaches 16 μm, the adjustment mechanism changed from initial multi-lamella mechanism to quasi-two dimensional one.

关 键 词：共晶合金CBr4-11.7%C2Cl6 层片间距 界面能各向异性 试样厚度 

分 类 号：TG244[金属学及工艺—铸造]