Co-curing process combining resin film infusion with prepreg and co-cured interlaminar properties of carbon fiber composites

In this article, the carbon fiber/epoxy resin matrix composite laminates were fabricated using a co-curing process combining resin film infusion (RFI) process with prepreg-autoclave process, called co-resin film infusion. A kind of unidirectional prepreg and its corresponding resin film were adopted. The compaction and defects of laminates cured by different processing were studied. Mode I and mode II interlaminar fracture toughness were adopted to evaluate the co-cured interlaminar properties of the co-curing laminates and were compared with those of laminates processed by the prepreg-autoclave process and the resin film infusion process. Moreover, the effects of lay-up type of prepreg part and resin film infusion part, isothermal dwell and epoxy tackifier of fiber preform were also studied. The results show that these factors have important effects on the processing qualities of the laminates cured by co-curing process, including resin-rich regions and voids, resulting in different interlaminar fracture toughness at the co-cured interface. Affected by the prepreg part and the resin film infusion part in the co-resin film infusion laminates, the mode I and mode II initial interlaminar fracture toughness of co-cured laminate lie between those of the prepreg laminate and resin film infusion laminate, and G(IC) at crack propagation stage for co-resin film infusion laminate are higher due to fiber bridging and deflection of crack. These results have close relationships with the compacting structure of fibers in prepreg and resin film infusion parts and the interfacial bonding between the two kinds of fiber and the matrix.