LaB_6-ZrB_2共晶复合材料的组织特征及控制

Characteristic and Controlling of LaB_6ZrB_2 Eutectic Composite Microstructure

用电弧炉和电子束悬浮区熔炉法制备了ＬａＢ６ＺｒＢ２共晶复合材料，并用ＳＥＭ和ＴＥＭ方法对其显微组织进行了研究。结果表明，ＬａＢ６ＺｒＢ２形成纤维状共晶组织，控制凝固条件可得到定向排列的组织，ＬａＢ６基体上均匀分布着直径为０２～１２μｍ的ＺｒＢ２纤维，纤维长度可达１００μｍ以上。对于固液界面为平面生长的试样，其结晶学取向关系为［００１］ＬａＢ６∥［００１］ＺｒＢ２，（１１０）ＬａＢ６∥（０１０）ＺｒＢ２。

LaB_6ZrB_2 eutectic composites were fabricated by using electric arc furnace and EBZM(electron beam zone melting) method and yields orientated ZrB_2 fibers in a LaB_6 matrix. The average diameter of ZrB_2 fibers is about 02～12 μm and the length can be more than 100 μm. For the samples with planar growth, orientatin relationship between the two phases is: LaB_6∥ZrB_2, (110)LaB_6∥(010)ZrB_2.