中文摘要：

顶部籽晶PMP法是一种熔融处理技术，对于制备高Jc的YBCO块材具有很好的效果，而定向凝固技术在制备具有良好取向的单晶时也经常用到。将这两种工艺结合起来（称作定向顶部籽晶PMP法（DTSPMP））可以制备具有良好单畴的YBCO块材。本文分析了籽晶传递作用和液相中溶质浓度的变化，研究了温度梯度对晶体取向和大晶粒持续生长的影响。使用扫描电镜分析了抽拉速率对微观组织的作用，结果表明在较低的抽拉速率下可以获得更大尺寸的单畴组织和细小弥散的211颗粒。

英文摘要：

Top-seeded power melting process （TSPMP） is an effective melting processing technique for the preparation of high Jc bulk YBCO. The directional solidification is also a quite common technique used to produce well-oriented cylinder grains. The two processes were combined （named Directional Top-seeded power melting process DTSPMP） to fabricate good YBCO bulk with well-oriented domains. The seed transferring effect and the change of the solute concentration in liquid were analyzed. The effects of temperature gradient （TG） on the orientation and continuous growth of large grains were also investigated. As a consequence of studying the microstructure dependence on pulling rate through canning electric microscopy（SEM）, it was found that the large domains can be obtained and the fine 211 particles were entrapped at a slower pulling rate.