Improving bonding strength of Al/CFRTP hybrid joint through modifying friction spot joining tools
Improving bonding strength of Al/CFRTP hybrid joint through modifying friction spot joining tools
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DOI：
10.1016/j.compositesb.2023.110588
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发表时间：
2023-02
期刊：
影响因子：
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通讯作者：
Peihao Geng;Hong Ma;Weihao Li;K. Murakami;Qian Wang;N. Ma;Y. Aoki;H. Fujii;Chuantong Chen
中科院分区：
文献类型：
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作者：
Peihao Geng;Hong Ma;Weihao Li;K. Murakami;Qian Wang;N. Ma;Y. Aoki;H. Fujii;Chuantong Chen
无销摩擦点连接（FSpJ）已被证明是一种具有竞争力的基于摩擦的连接技术，用于制造金属/碳纤维增强热塑性塑料混合接头。本文研究了通过工具改进来提高硅烷涂层6061-T6铝合金与碳纤维增强聚酰胺-6（CF/PA 6）FSpJ接头性能的可行性。分析和比较了4种不同旋转速度的工具（OT、NT、CT和RT）的接头界面结构、结合强度和断口形貌。实验验证的三维有限元模型也被建立，以帮助理解FSpJ过程。尽管修改了工具形状，共价键合占主导地位的界面结合力，其中纳米级扩散层的形成被见证，没有新的类型的共价键产生。所得的断裂表面主要由内聚失效模式，表明再固化树脂和硅烷化Al表面之间的强化学键合。在NT的情况下，拉伸剪切力的降低是由于微观尺度的空隙和孔隙的广泛形成和合并。通过使用CT和RT工具缓解了这一问题，通过这些工具控制热输入，从而获得更均匀的热场。从热过程和力学性能的综合评价，CT工具被推荐用于铝和CF/PA 6的FSpJ，因为它提供了一个更均匀的温度分布和改善宏观机械联锁在界面处具有良好的润湿条件，充分的化学反应和有效的连接面积，和较低的拉伸残余应力，与其他工具相比，因此显示出最高的剪切力。
Pinless friction spot joining (FSpJ) has proven to be a competitive friction-based joining technique for fabricating metal/carbon fiber-reinforced thermoplastics hybrid joints. The present study investigated the feasibility of tool modification to improve the property of the silane-coated 6061-T6 Al alloy and carbon fiber-reinforced polyamide-6 (CF/PA6) FSpJ joint. The interfacial structure, bonding strength and fracture surface of the joints obtained by four tools, viz, old flat (OT), new flat (NT), concave-shaped (CT) and ring-shaped tools (RT) with different rotation speeds, were analyzed and compared. An experimentally validated three-dimensional finite element model was also built to help understand FSpJ process. Despite modifying the tool shape, covalent bonding predominated the interfacial bonding force where the formation of nanoscale diffusion layers was witnessed with no new type of covalent bonds generated. The resultant fracture surface was dominated by the cohesive failure mode, suggesting strong chemical bonding between the re-solidified resin and silanized Al surface. The decrease in tensile shear force in the case of NT was due to the extensive formation and coalescence of microscale voids and porosities. This was mitigated by using CT and RT tools, from which the heat input was controlled leading to a more homogenized heat field. From the combined evaluation of thermal process and mechanical characteristics, CT tool was recommended for the FSpJ of Al and CF/PA6 because it offered a more uniform temperature distribution and improved macro-mechanical interlocking at the interface with good wetting conditions, sufficient chemical reaction and effective joining area, and lower tensile residual stresses, in comparison with other tools, and hence showed the highest shear force.