论文部分内容阅读
利用定向凝固技术制备了取向良好的 YBCO 棒材,其 a-b 晶面与提拉方向的夹角小于 5°。为研究 YBCO 生长的各向异性及其定向凝固机制,分别通过空淬及炉冷的方式获取了熔体生长的 YBCO 晶粒形貌及固液界面形貌。YBCO 晶粒呈现片层状结构,其长厚比约为 2~5。晶体生长的固液界面清晰反映出了外延生长的特征。基于上述结果,讨论了 YBCO 的定向凝固机制,认为 YBCO 的定向凝固是由择优生长及外延生长两阶段构成,这很好地解释了本文的试验结果。
YBCO rods with good orientation were prepared by directional solidification technology. The angle between the a-b crystal plane and the pulling direction was less than 5 °. In order to study the anisotropy of YBCO growth and its directional solidification mechanism, the YBCO grain morphology and solid-liquid interface morphology of melt growth were obtained by air quenching and furnace cooling respectively. YBCO grain lamellar structure, the aspect ratio of about 2 ~ 5. Solid-liquid interface crystal growth clearly reflects the characteristics of epitaxial growth. Based on the above results, the directional solidification mechanism of YBCO is discussed. It is considered that the directional solidification of YBCO is composed of two stages of preferential growth and epitaxial growth, which well explain the experimental results of this paper.