| With the rapid development of science and technology,polymer composites are receiving more and more attention in order to meet the needs of production and development,and they have replaced many traditional materials by virtue of their excellent properties.Epoxy resin is a thermosetting polymer with strong mechanical properties,good stability and high bonding capacity.Carbon Fiber Reinforced Plastics(CFRP)made from epoxy resin as a matrix and carbon fibers have the advantages of low mass,high specific modulus and high strength,which make them widely used in aerospace,automotive,construction and electronic packaging.However,the properties of cured epoxy resin and the bonding property of the interface between the resin matrix and carbon fibers are lower.In addition,epoxy resins and CFRP will be exposed to harsh aging environments when applied in some engineering fields,resulting in severe degradation of their properties.Carbon fiber metal laminates(FMLs),consisting of epoxy resin,carbon fiber and AZ31B magnesium alloy,are widely used in aerospace and military industries because of their high strength and light weight.However,FMLs also have some disadvantages,in addition to the problem of poor properties of the epoxy resin matrix and the carbon fiber layer,there are also poor bonding between AZ31B magnesium alloy and carbon fiber layer,which makes FMLs prone to delamination.Therefore,solving the problems faced above is of great importance for the development and application of composite materials.In this paper,epoxy resin composites and CFRP were prepared by adding halloysite nanotubes(HNT)and indocalamus fiber to epoxy resin respectively,different ageing environments where epoxy resin and CFRP are located were simulated artificially,and the effects of adding HNT and indocalamus fiber on the properties of epoxy resin and CFRP were analysed by testing the mechanical properties of epoxy resin before and after ageing,Infrared spectroscopy,glass transition temperature(T_g)and the mechanical properties of CFRP before and after ageing,and the fracture morphology of epoxy resin and CFRP were observed,and their strengthening and ageing mechanisms were analysed.For the FMLs,the AZ31B magnesium alloy comprising the FMLs was first surface treated(MAO-AZ31B)using micro-arc oxidation(MAO),and then the MAO-AZ31B was combined with the epoxy resin and carbon fiber mentioned above to make the FMLs,by testing the flexural properties of the FMLs and observing the interlayer bonding of the FMLs,the MAO treatment,HNT and indocalamus fiber were analysed fibres on the properties of the FMLs.The main findings of this paper are as follows:1.The addition of HNT has a significant effect on the properties of the epoxy resin and CFRP.With the increase of HNT content,the tensile and flexural properties of epoxy resin first increased and then decreased,when the HNT content was 2 wt.%,the tensile and flexural properties reached the highest,and HNT also improved the T_g of epoxy resin.The tensile and flexural properties of the 2 wt.%HNT reinforced CFRP are also improved compared to the neat CFRP,and the HNT enhances the properties of the epoxy resin and the bonding property of the interface between the resin matrix and the carbon fibers.2.The incorporation of indocalamus fiber had a significant effect on the performance of the epoxy resin and CFRP.With the increase of indocalamus fiber content,the tensile and flexural properties of the epoxy resin showed a trend of increasing and then decreasing,and the tensile and flexural properties of the epoxy resin reached the highest at 20 wt.%of indocalamus fiber content,and the T_g of the epoxy resin was also improved by the addition of indocalamus fiber.Compared to neat CFRP,the tensile and flexural properties of CFRP are significantly improved by adding 20 wt.%indocalamus fiber to the epoxy resin matrix.3.The magnitude of ageing of epoxy resin and CFRP in 20°C water,60°C water and 20°C HCl solution(5 wt.%):60°C water>20°C HCl solution(5 wt.%)>20°C water.Compared to the ageing of neat epoxy resin and neat CFRP,the ageing of HNT reinforced epoxy resin and HNT reinforced CFRP is less severe,indicating that HNT improves the resistance of epoxy resin and CFRP to immersion ageing.4.MAO,HNT and indocalamus fiber have a significant effect on the properties of FMLs.Compared to the neat FMLs,the flexural properties of MAO-AZ31B/FMLs,MAO-AZ31B/HNT/FMLs and MAO-AZ31B/indocalamus fiber/FMLs were all improved.By comparing the flexural properties of MAO-AZ31B/FMLs,the addition of HNT and indocalamus fiber in turn leads to a further improvement in the flexural properties of FMLs.The bonding ability between the AZ31B magnesium alloy and the carbon fiber layers is enhanced as can be seen by the interlayer bonding morphology. |
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