Fabrication And Properties Investigation Of Carbon Fiber Reinforced Magnesium-Based Composite Laminates

GLARE laminates (glass fiber/epoxy resin reinforced aluminum laminates) have been used as covering material applied on large aircraft. However, epoxy resin adhesive laminates have low interfacial bonding strength, and are liable to peeling between layer interfaces. In addition, epoxy resin adhesive has poor humidity resistance and high temperature stability, generally its service temperature does not exceed150℃. Therefore, It has important theoretical and practical significance to seek and develop a new and more excellent composite laminate to replace GLARE laminate.This paper prepared monolayer carbon fiber cloth reinforced magnesium-based composite laminate by hot-pressing, preliminarily explored the preparation technology, and its structure and properties were studied.Carbon fibers reinforced magnesium matrix composite laminates were fabricated by using vibration assisting hot-pressing with choosing AZ31B magnesium alloy sheet as the base material, T-300carbon fiber woven cloth as reinforcing material, low melting point Mg69.7Zn28.9Al1.4ternary eutectic alloy powder (its melting point is339℃) as the solder between the matrix and reinforced phase.This study examined the influence of hot-pressing loads, holding time and vibration on the tensile mechanical property, interfacial bonding strength, and interfacial microstructure of composite laminates, and its mechanism was discussed. Interfacial bonding strength and room temperature tensile property of composite laminates prepared by different processes were tested by electronic universal testing machine. Scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS) and X ray diffraction (XRD) were utilized to investigate the interfacial microstructure and to analyze the interfacial fracture surface and identify phase components.The results are as follows.(1) Composite laminates with high interfacial bonding strength and room temperature tensile property can be prepared by vibration assisting hot-pressing with low melting point eutectic alloy powder as the solder.(2) The interfacial bonding strength was enhanced significantly with the increase of hot pressing loading, and increased slightly with the prolonged holding time, and vibration has a great important influence on interfacial bonding strength. The composite laminate exhibits the highest interfacial bonding strength up to8.7MPa under loading of90MPa, vibration of50Hz and holding time of120s.(3) The room temperature tensile strengths of composite laminates prepared by various loads(10MPa,30MPa,60MPa and90MPa) are raised with increasing loading, and obtain the highest value of311.1MPa at the load of60MPa. When further increasing the load to90MPa, however, the tensile strength drops drastically. Meanwhile, the room temperature longitudinal tensile strength of composite laminates increases slightly with the prolonging of holding time.(4) The bonding interface of the solder and the matrix is mainly determined by diffusion reaction, and its bonding strength is higher than the bonding strength between carbon fiber and solder.(5) The wettability between carbon fibers and the solder is closely related to the external loading.The interfacial tensile fractures indicate that the solder only wet the carbon fibers at load of90MPa.It is concluded that the external loading can supply sufficient drive force to overcome various resistances for solder to infiltrate and flow at the gaps of carbon fiber cloth, which makes the solder wet carbon fibers and thus forms strong interface bonding. Macroscopical mechanical property of carbon fiber reinforced magnesium matrix composite laminates is determined by interfacial bonding strength and the integrity of carbon fibers cloth. When carbon fiber cloth was damaged, the reinforcement effect would be reduced obviously. Optimal comprehensive mechanical property can’t be achieved when interface bonding strength is low. Therefore, Only forming a strong bonding interface, and ensuring the integrity of the carbon fiber composite laminates can get the best comprehensive mechanical properties.