丽文哈贝壳螺旋微结构研究

Research of Helicoidal Microstructure of Meretrix Lusoria Shell

对丽文哈贝壳的微结构进行了扫描电镜(SEM)观察,观察显示它是由无机霰石层和有机胶原蛋白组成的一种生物陶瓷复合材料,其中无机霰石层平行于贝壳表面整齐排列。观察也显示这些霰石层是由长而薄的霰石片所组成,不同霰石层中的霰石片具有不同的方向,构成螺旋等铺层形式。更仔细的观察显示每一霰石片又是由长而细的霰石纤维所组成,最细的霰石纤维具有纳米的尺度。根据在贝壳中观察到的螺旋结构,进行了螺旋结构和平行结构最大拔出力的比较实验研究,结果显示螺旋结构的最大拔出力大于平行结构的最大拔出力,它使贝壳具有高的强韧性。研究结果对高性能仿生陶瓷复合材料设计提供了有益指导。

The microstructure of a Meretrix lusoria shell was observed with a scanning electronic microscope （SEM）. It was showed that the shell was a bioceramic composite consisting of aragonite layers and collagen protein. The aragonite layers consisted of thin and long aragonite sheets which were upright to the layers placed the sheets. The observation also showed that the aragonite sheets in different layers possess different orientations and composed different structures. A kind of helicoidal structure was found, in which, the aragonite sheets in an arbitrary aragonite layer made a revolving angle against the sheets in their neighboring layers. The maximum pullout force of the fibers in a helicoidal structure was tested and compared with that of the fibers in a parallel structure. It was showed that the maximum pullout force of the fibers in the helicoidal structure was markedly larger than that of the fibers in the parallel structure. The more the fiber numbers, the bigger the maximum pullout force of the fibers in the helicoidal structure compared with that of the fibers in the parallel structure.