Abstract

This study developed a kind of non-woven carbon tissue reinforced adhesive film (NWCTRAF) with high bonding strength and reliability by interleaving the NWCT into the adhesive film. The manufacturing process, bonding strength, Weibull distribution, metallography of cross-section, and fracture surface morphology of NWCTRAF specimens were investigated. The results showed that the average bonding strength and Weibull characteristic strength (WCS) of single lap joint (SLJ) were 27.4a and 28.2 MPa, which increased by 17.6% and 15.1%, respectively compared with the blank specimen, and the Weibull modulus risen from 9.51 to 18.72, which indicated that NWCTRAF specimens had higher bonding reliability. The mechanism of micro-crack formation was obtained by analyzing the cross-section of loading 95% WCS without visible damage. The metallographic section showed that the microcracks of the blank specimen originated from the interface between carbon fiber-reinforced polymer (CFRP) and adhesive layer, while the microcracks of the NWCTRAF specimen originated from the resin-rich regions between the carbon fiber fabric layers in CFRP. Typical failure modes were gained from optical microscope and SEM. Failure modes of blank specimen included more interface failure of CFRP-adhesive and Al-adhesive, while NWCTRAF specimen had more carbon fiber tearing and delamination of CFRP. The fracture morphology of adhesively cohesive failure included the pull-out of short carbon fibers and the appearance of rough and multi-stage resin in the NWCTRAF specimen, which improved the toughness of the adhesive layer. The bridging effect of short carbon fibers in the NWCTRAF disperse and transfer stress to CFRP and fail at resin-rich regions of CFRP, decrease the bonding interface's direct failure, and improve the bonding strength and reliability.

摘要

本研究通过将NWCT交错到胶膜中，开发了一种具有高粘合强度和可靠性的无纺碳组织增强胶膜（NWCTRAF）。研究了NWCTRAF试样的制造工艺、结合强度、威布尔分布、断面金相和断口形貌。结果表明，单搭接接头（SLJ）的平均结合强度和威布尔特征强度（WCS）分别为27.4a和28.2 MPa，与空白试件相比分别提高了17.6%和15.1%，威布尔模量提高了。从 9.51 到 18.72，表明 NWCTRAF 试件具有更高的粘合可靠性。通过分析加载 95% WCS 且无可见损伤的横截面，获得了微裂纹的形成机制。金相切片显示，空白试样的微裂纹起源于碳纤维增强聚合物（CFRP）与粘合层之间的界面，而NWCTRAF试样的微裂纹起源于CFRP中碳纤维织物层之间的富树脂区域。 . 从光学显微镜和扫描电镜获得了典型的失效模式。空白试件的破坏模式包括更多的CFRP-adhesive和Al-adhesive的界面破坏，而NWCTRAF试件的碳纤维撕裂和CFRP分层较多。NWCTRAF试件中黏聚破坏的断裂形态包括短碳纤维的拉出和粗糙的多级树脂的出现，从而提高了粘合层的韧性。