离子减薄技术在藤纤维力学性质测试上的应用

为构建棕榈藤材纤维细胞壁结构模型，探索棕榈藤强韧机理，选择高地钩叶藤为研究对象，将离析获得的藤皮纤维运用场发射双束扫描电镜产生的离子束经过离子腔加速，对纤维细胞两侧表面对称进行纳米级别的减薄，采用Instron微型力学试验机进行拉伸测试，并用激光共聚焦显微镜对纤维的断口面积进行测量，计算单纤维的拉伸强度和拉伸弹性模量。用超薄切片机对藤试样表面进行抛光，其中对纤维细胞壁要进行减薄的，则要先对该试样进行喷金处理，然后应用纳米压痕仪对高地钩叶藤纤维细胞壁进行纳米压痕试验，采用Oliver and Pharr理论计算纵向硬度和纵向弹性模量。研究结果表明，高地钩叶藤单纤维拉伸强度、拉伸弹性模量分别为475.21 MPa和7.42 GPa；纤维拉伸强度和断裂伸长率随藤材高度增加（即随藤龄减小）而逐渐减小。纤维拉伸强度、拉伸弹性模量及断裂伸长率，均表现为藤皮＞藤芯。减薄处理的藤皮纤维拉伸强度与离析的单纤维拉伸强度变化趋势相反，而单纤维拉伸弹性模量变化趋势与离析的纤维一致。高地钩叶藤藤皮纤维细胞壁纵向硬度和纵向弹性模量分别为0.25和7.01 GPa，藤皮纤维细胞壁纵向硬度和纵向弹性模量，随藤材高度增加（即随藤龄减小）而逐渐减小。中部和梢部藤皮纤维减薄后的微柱的纵向弹性模量分别为6.20和3.87 GPa，比对照纤维分别减小了24.2%和12.2%。中部和梢部藤皮纤维减薄后的细胞壁纵向硬度分别为0.24和0.19 GPa，均略小于未进行减薄处理的对应的纤维细胞壁的纵向硬度。减薄处理后，高地钩叶藤单纤维拉伸强度和拉伸弹性模量均有较大程度下降，纵向弹性模量和纵向硬度略有下降。表明纤维细胞壁的外层拉伸强度、拉伸弹性模量、纵向硬度和纵向弹性模量较内层大，而断裂伸长率却小于内层。

The application of ion-thinning technology in measurement of the mechanical properties of rattan fiber

In order to construct a model for fiber wall structure, and research on the mechanism of rattan tenacity, Plectocomia himalayana was chosen as the research material. After the cortex fiber being isolated, two sides of the fiber cell wall were thinned symmetrically at nanometer level using the ion beam generated by FIB-SEM. The fracture area of the fiber was measured by Confocal Laser Scanning Microscope after the tensile test by Instron Micro Tester, and then the tensile strength and tensile elastic modules of the single fiber were calculated. The surface of rattan sample was polished by Ultramicrotome, and the sample should be sprayed with gold first if the cell wall of fiber was to be thinned, and then nanoindentation test was carried out on the cell wall of rattan by Nanoindentation, and the longitudinal hardness and longitudinal elastic modulus of fiber cell wall were calculated in Oliver and Pharr theory. The results showed that the tensile strength and tensile elastic modules of single fiber were 475.21 MPa and 7.42 GPa, respectively. The tensile strength and elongation at break of fiber decreased with the increase of rattan height (i.e. with the decrease of rattan age), and the fiber tensile strength and elongation at break of cortex were bigger than those of core. After thinning treatment, the change trend of the tensile strength of cortex fiber was opposite to that of the isolated fiber, while the change trend of the tensile elastic modules was consistent with that of the isolated