Abstract The effect of initial fiber orientation and welding conditions on the mechanical properties and microstructure of 30 wt% glass-fiber-reinforced polyamide 66 was systematically evaluated. For all conditions studied no significant change in the polymer matrix was evidenced. However, fibers in the welded zone were reoriented toward the squeeze and vibration flows and this reorientation is related to the appearance of cavities, as evidenced by high-resolution synchrotron-based X-ray microtomography. It is shown that stress at break values of the welded samples increase with the thickness of the weld zone together with the minimum value of the fiber orientation tensor component in the tensile direction. A drop of strain at break is also related to an increase in the fibers’ concentration in the weld. The maximum void volume fraction being measured on samples which have the thickest welded zones, counterintuitively it does not induce lower stress at break.

中文翻译：

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振动焊接玻璃纤维增​​强聚酰胺 66 的显微结构-机械性能关系：高分辨率 X 射线显微断层扫描研究

摘要 系统地评估了初始纤维取向和焊接条件对 30 wt% 玻璃纤维增​​强聚酰胺 66 的机械性能和微观结构的影响。对于所研究的所有条件，没有证明聚合物基质发生显着变化。然而，焊接区中的纤维被重新定向为挤压和振动流，这种重新定向与空腔的出现有关，基于高分辨率同步加速器的 X 射线显微断层扫描证明了这一点。结果表明，焊接试样的断裂应力值随着焊接区厚度的增加以及拉伸方向上纤维取向张量分量的最小值而增加。断裂应变的下降也与焊缝中纤维浓度的增加有关。