The creation and ultrastructure of kink-bands in flax fibres are key issues for developing more and more performing biobased composite materials. Nevertheless, despite many hypotheses and structural characterisation, the exact origin of kink-bands and the moment they appear remain unexplained. Here, by using cutting-edge techniques such as microtomography, a range of flax stems and fibres, from the green stem to stretched fibres, were morphologically explored. The study shows that all the extracted fibres, whether scutched, combed or stretched, contain significant amounts of kink-bands, which can be identified by the large pores they contain. On the other hand, at the scale of the green or retted stems, tomographic analysis does not reveal any kink-bands. These original observations suggest that the stress undergone by the plants during their growth is not sufficient, without major growth or lodging accidents, to generate these structural defects; the latter are only revealed after mechanical extraction of the fibres. Hypotheses regarding the kink-band appearance deformation levels are also given to complete the observations.

亚麻纤维中扭结带的产生和超微结构是开发越来越高性能的生物基复合材料的关键问题。然而，尽管有许多假设和结构特征，扭结带的确切起源和它们出现的时间仍然无法解释。在这里，通过使用诸如显微断层扫描等尖端技术，对从绿色茎到拉伸纤维的一系列亚麻茎和纤维进行了形态学探索。研究表明，所有提取的纤维，无论是刨花、精梳还是拉伸，都含有大量的扭结带，这些扭结带可以通过它们所含的大孔来识别。另一方面，在绿色或沤茎的尺度上，断层扫描分析没有显示任何扭结带。这些原始观察表明，植物在生长过程中所承受的压力不足以产生这些结构缺陷，如果没有重大的生长或倒伏事故；后者仅在纤维的机械提取后才显露出来。还给出了关于扭结带外观变形水平的假设以完成观察。