中文摘要：

采用电子束悬浮区熔装置（EBFZM）制备了Si-TaSi2共晶自生复合场发射材料,系统地研究了Si-TaSi＋2共晶的定向凝固组织特征.当凝固速率在0.3～9.0mm/min范围内变化时,均可获得Si-TaSi2共晶自生复合材料,具有高精确取向的TaSi2纤维在硅连续基体中均匀分布.随着凝固速率的增大,TaSi2纤维的直径和平均间距减小,面密度和体积分数增大.采用零功率法考察了不同凝固速率时的固-液界面形貌.当凝固速率由0.3mm/min变化到5.0mm/min时,固-液界面经历了平界面→浅胞状界面→胞状界面→平界面的演化过程.

英文摘要：

The directionally solidified Si-TaSi2 eutectic in situ composite for field emission was prepared with the electron beam floating zone melting （EBFZM） technique. The microstructure characteristic of Si-TaSi2 eutectic was systematically investigated. The Si-TaSi2 eutectic in situ composite, which has high-aligned and uniformly-distributed T aSi2 fibers in the Si matrix, can be obtained when the solidification rate changes from 0.3mm/min to 9.0mm/min. With the increase of the solidification rate, the diameter and the inter-rod spacing of the TaSi2 fibers are decreased, while the density and the volume fraction of the fibers are increased. The solid/liquid interface is studied by the zero power method as well. When the solidification rate varies from 0.3mm/min to 5.0 mm/min, the solid/liquid interface morphology has the following evolution processing： planar interface→shallow cell interface→cell interface→planar interface.