通过熔融纺丝制备相同条件中间相沥青原丝,分别施加3.6,10.8 MPa张力进行预氧化处理,用XRD,SEM,HRTEM等手段对两组纤维的取向结构进行研究。结果表明:预氧化过程中施加张力有利于提高纤维取向度,张力越大,纤维取向度越高,微晶沿纤维轴向排列更加整齐有序,晶面间距较小,微晶尺寸较大;经2 800℃石墨化处理后,施加3.6 MPa和10.8 MPa张力纤维取向度分别达到94.76%和95.25%。 The mesophase pitch billets were prepared by melt spinning. Pretreated with 3.6, 10.8 MPa tensile force respectively, the orientation structure of the two fibers was studied by means of XRD, SEM and HRTEM. The results show that the tension is conducive to increase the degree of fiber orientation during pre - oxidation. The larger the tension and the higher the degree of fiber orientation, the more uniform and orderly arrangement of the crystallites along the fiber axis, the smaller interplanar spacing and the larger crystallite size. After graphitization at 2 800 ℃, the orientation degrees of tensile fibers of 3.6 MPa and 10.8 MPa were 94.76% and 95.25% respectively.