Al-ZrOCl_2体系原位生成Al_3Zr的孪晶生长

TWIN GROWTH OF IN-SITU FORMED Al_3Zr IN THE SYSTEM Al-ZrOCl_2

借助于ＸＲＤ和ＴＥＭ研究了Ａｌ－ＺｒＯＣｌ２体系熔体反应生成的原位复合材料，结果表明： 内生增强体为 Ａ１３Ｚｒ和 Ａ１２Ｏ３颗粒，Ａ１３Ｚｒ晶体形貌主要以多面体和长方体形状为主，其平均尺寸约 为１·２６μｍ，最大尺寸为４μｍ；纵横比在１．５～２．０之间．这两种形状的晶体表面均存在生长小面（ｆａｃｅｔ）， 首次发现 Ａｌ_３Ｚｒ晶体以孪晶方式生长，孪晶面为（１，１，４），孪生方向为［２，２，ｌ］．对Ａｌ_３Ｚｒ晶体的结构 分析发现，该晶体存在四个密排面，它们分别是（１，１，４），（１，１，４）；（１，１，４）和（１，１，４）．

The in situ composite synthesized by melt reaction in the system Al-ZrOCl2 has been investigated by XRD and TEM. The result showed that in situ reinforcements are composed of Al3Zr and Al2O3 particles. Al3Zr particulate is mainly in the shape of polyhedron and rectangle. The average size is about 1.26 μm. The maximum size is 4 μm. The length/width ratio of Al3Zr particulate is in the range of 1.5-2.0. There are facets on the surface of Al3Zr crystal. It is firstly found that Al3Zr crystal grows in the form of twins. The twin plane is (1,1¯,4¯). The twinning direction is [2,2¯,1]. Moreover, it has been found that there are four close packing planes in Al3Zr crystal, such as (1,1,4), (1¯,1¯,4), (1,1¯,4) and (1¯, 1, 4) according to the analysis of Al3Zr structure.