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采用光学显微镜、透射电子显微镜和X射线衍射仪研究Mg2B2O5晶须增强镁基复合材料的铸态组织及Mg2B2O5/AZ91D界面反应产物。结果表明:Mg2B2O5晶须具有孪晶结构,其孪生面和晶体生长方向分别为(202)和[010];部分Mg2B2O5晶须中存在MgB4O7颗粒相;在基体晶界与Mg2B2O5晶须之间存在等轴状Mg2Si相;Mg2B2O5/AZ91D界面处存在厚度不均匀的MgO和MgB2相界面层。尽管Mg2B2O5、MgO和MgB2之间没有确定的晶体学位相关系,但在特定Mg2B2O5晶须表面观察到(202)Mg2B2O5//(002)MgO,[010]Mg2B2O5//[110]MgO和(002)MgO//(0001)MgB2,[110]MgO//[2110]MgB2取向关系。最后,讨论Mg2B2O5晶须对复合材料组织结构和性能的影响。
The as-cast microstructure and Mg2B2O5 / AZ91D interfacial reaction products of Mg2B2O5 whisker reinforced magnesium matrix composites were studied by optical microscope, transmission electron microscopy and X-ray diffraction. The results show that the Mg2B2 O5 whiskers have twin structure with (202) and [010] growth directions of the twin planes and [010]; MgB4O7 phase exists in some Mg2B2O5 whiskers; and there exists between the matrix and Mg2B2O5 whiskers Axial Mg2Si phase; Mg2B2O5 / AZ91D interface exists uneven thickness of MgO and MgB2 phase interface layer. Although there is no definite crystallographic phase relationship between Mg2B2O5, MgO and MgB2, (202) Mg2B2O5 // (002) MgO, [010] Mg2B2O5 // [110] MgO and (002) MgO // (0001) MgB2, [110] MgO // [2110] MgB2 orientation relationship. Finally, the effects of Mg2B2O5 whiskers on the microstructure and properties of the composites were discussed.