Investigation on forward and backward transfer process during carbon fiber/epoxy composites dry-sliding against iron alloy

• Published in: Science China. Technological sciences 2022-11, Vol.65 (11), p.2564-2572
• Main Authors: Lu, LongSheng, Li, ZeHong, Fang, HeZhengZi, Xie, YingXi, Wang, WenTao
• Format: Article
• Language: English
• Subjects: Bearing capacity; Carbon fiber reinforced plastics; Carbon fibers; Coefficient of friction; Coefficient of variation; Composite materials; Engineering; Epoxy resins; Ferrous alloys; Fiber composites; Fiber reinforced polymers; Friction; Iron; Iron alloys; Metal surfaces; Polymer matrix composites; Tribology
• ISSN: 1674-7321; 1869-1900
• DOI: 10.1007/s11431-022-2137-8

Carbon fiber reinforced polymer (CFRP) composites with high load-bearing capacity are currently ideal materials in tribological load systems. One of the unique features during the friction process of CFRP/metal is the in-situ formation of an ultrathin and uniform transfer film on the metal surface, and the related initial/transfer mechanism is very important but still unclear. Recent studies mainly focus on the one-way transfer process of CFRP to the metal surface, that is, forward transfer; whereas another easily overlooked issue is that the metal material also transfers backward to the CFRP surface. Herein, we firstly prepared carbon fiber/epoxy resin composites (CF/EP) by the hot-pressing method and then carried out friction tests with iron alloy as the control material. The underlying mechanism of the forward/backward transfer process is revealed by controlling the morphological evolution and iron content of the transfer film on worn CF/EP. According to the variation law of friction coefficient with time, the interfacial friction is divided into three different stages, among which the behaviours of “micro-convex contact” and “epoxy exfoliation” occur throughout the whole procedure. We believe this work could provide a meaningful reference for studying the friction behaviour and mechanism, especially the forward and backward transfer between composites/metals, and further broaden its emerging applications in future energy, aerospace and rail transportation.