铋生长方式的转变及其固-液界面能的确定  

Crystal-Growth Transition and the Solid-Liquid Interface Energy of Bismuth

作　　者：坚增运[1] 杨晓琴[1] 吕士勇[1] 李卫军[1] 常芳娥[1] 

机构地区：[1]西安工业大学材料与化工学院,西安710032

出　　处：《西安工业大学学报》2010年第3期253-257,共5页Journal of Xi’an Technological University

基　　金：国家自然科学基金项目(50571076;50671075);国家973项目(2006CB605202)

摘　　要：为了深入研究铋的凝固组织及固液界面能的变化规律,采用熔盐净化结合循环过热的方法,对铋的过冷度及凝固组织特征进行研究,试验结果表明：过冷度不仅影响铋凝固后晶粒的尺寸,而且也影响晶粒的形貌.根据铋凝固后的晶粒形貌,确定出了铋从小平面生长转变为中间方式生长的临界过冷度和中间方式生长转变为连续生长的临界过冷度分别为49 K和95 K.在此基础上,利用临界过冷度转变模型对铋的固-液界面能进行了预测,从两个临界过冷度所计算的固-液界面能值几乎相等.两者的误差在144~544 K范围只有1.44%~2.55%.其预测结果与形核过冷度法所报道的实验结果相吻和,其误差小于1.72%In Order to find the change regularity of the solidification structure and solid-liquid interface energy for bismuth, the undercooling and solidification structure of bismuth denucleated by cyclical superheating and the chloride flux （SnCl2） is studied in this paper. The results show that the undercooling influences not only the grain size, but also the grain morphology of bismuth. In terms of the grain morphology,it is determined that the critical undercoolings for bismuth from lateral growth to intermediary growth ΔT and that from intermediary growth to continuous growth ΔT are 49 K and 95 K, respectively. The solid-liquid interface energy of bismuth predicted from ΔT =49 K is almost equal to that from ΔT = 95 K. The percentage error between the solid-liquid interface energy predicted from ΔT = 49 K and that from ΔT = 95 K is as small as 1. 44% -2. 55% when the temperature is in the region from 144 to 544 K. The present results of the solid-liquid interface energy predicted from the critical growth transition undercoolings for bismuth are also in very good agreement with the reported results from the nucleation method. The percentage error between them is smaller than 1.72%.

关 键 词：铋 过冷度 组织 生长特性 固-液界面能 

分 类 号：TG111.4[金属学及工艺—物理冶金]