橫晶与纤维界面的形态观察

在纤维表面的异相成核密度达到足够高的程度时,晶粒的生长由径向转变为沿垂直于纤维表面的方向生长,即横晶生长(transcrystalline growth)。在许多纤维增强的高聚物复合材料中都可以得到横晶结构。横晶的结构和球晶是完全相同的。横晶是球晶的一种特殊情况,即取向球晶。虽然横晶中片晶的生长方向是相同的,但是在横晶与纤维之间,即在纤维表面区域却是非取向的。利用刻蚀剂或离子对材料进行刻蚀处理,控制刻蚀程度,可以使纤维和取向的横晶之间的非取向区首先被刻蚀液或离子刻蚀破坏掉。而取向的横晶结构区域则被保留下来。用扫描电子显微镜就可以观察到这两种结构区。

INTERFACE MORPHOLOGY BETWEEN FIBERS AND TRANSCRYSTALLINE REGION IN THE FIBER REINFORCED COMPOSITES

In the fiber reinforced polymer composites, there is an interface region between the fibers and the oriented transcrystalline region. The interface region can be identified with SEM after the composite is etched by the permanganic etchant or ion beam. The interface region is about 3-4μm and the crystals in it are very small and have many defects because in the initial stage of the crystallization the rate of the nucleation and the density of the nucleus around the fibers are very high. In the oriented trancrystalline region the lamella very slowly grow at the high crystallization temperature and their crystalline strucure is perfect. Therefore, during the etching, the interface region and amorphous parts between the lamella in the transcrystalline region is first destroyed by etchant or ion beam but the lamella are mantained and exposed.