The Preparation And Performance Of Carbon Fiber Metal Laminate

Carbon fiber metal laminates have attracted wide attention due to their large deformation and high strength and stiffness.They are mainly used in skin structures of the fuselage and wings of aircraft.The interface structure is the main influencing factor of its comprehensive properties,so how to optimize the interface properties of this material has become an important research direction.In this study,a nanoporous structure was prepared on the surface of aluminum?Al?and titanium?Ti?by anodic oxidation method using phosphoric acid as an electrolyte firstly.Scanning electron microscopy was used to characterize the nanoporous structure.Secondly,nylon 6?PA6?was used as the matrix,while glass microbeads?GB?and nano CaCO3 used as matrix filling particles,carbon fiber?CF?and Al plate/Ti plate used as the reinforcement.Carbon fiber metal laminates filled with inorganic particles?IP?were prepared by hot pressing.The effects of anodic oxidation process parameters,carbon fiber pre-impregnation process and inorganic particles on the mechanical properties and micro-morphology of carbon fiber metal laminates were investigated.The toughening mechanism of Nano-CaCO3 and GB in fiber metal laminates under bending,shear and impact conditions was disgussed.The mechanical properties and micro morphology of inorganic particles?IP?and aluminum alloy reinforced carbon fiber metal laminate?Al/IP/CF/PA6?and titanium alloy reinforced carbon fiber metal laminate?Ti/IP/CF/PA6?were compared.The conclusions were listed as below:?1?Pre-impregnate CF with 4wt%PA6/ethanol solution can make CF enter the CF bundle without damaging the carbon fiber performance.CF pre-impregnation process can improve the bond strength between carbon fiber and the PA6 matrix.Besides,it enhance the mechanical properties of the PA6 composites.The bending strength and impact strength of Al/CF/PA6 after CF pre-impregnation are increased by22.2%and 19.7%,respectively.?2?As the increase of the oxidation voltage,electrolyte concentration,and oxidation time,the pore size and depth of anodized nanopores will increase,the nanopore spacing will decrease.When the oxidation voltage is at 120V,the oxidation time at 7 min and the concentration of the phosphoric acid electrolyte at 40 g/L,nanopores with an average pore diameter of 130 nm and round shape can be prepared.When the oxidation voltage is at 30V,the oxidation time at 25 minutes and the concentration of the phosphoric acid electrolyte at 130 g/L,nanopores with an average pore diameter of 80 nm can be prepared,but the shape of the pores is not round enough.?3?The shape and size of anodized nanopores have effect on the mechanical properties of carbon fiber metal laminates.Nanopores with larger pore diameters and better shapes can allow more nylon matrix to enter during the hot pressing process,increasing the bonding strength between the metal and the matrix,finally improving the mechanical properties of the composite laminate.Under the conditions of the voltage of 120V,oxidation time of 5min,and phosphoric acid electrolyte concentration of 40g/L,the comprehensive performance of the Al/CF/PA6 composite laminate reaches the maximum,with the bending strength of 303.6MPa,the shear strength of 41.8MPa,and the impact strength of 90.7 kJ/m².?4?The addition of nano-CaCO3 and GB both can improve the mechanical properties of carbon fiber metal laminates,and nano-CaCO3 has the better effect.Because nano-CaCO₃ can enter the nanopores of the metal.However,the effect of the mechanical properties of composite laminates is not significant enough.This is because the interlayer delamination and debonding are the most important failure modes of carbon fiber metal laminates.?5?Ti/IP/CF/PA6 has better mechanical properties than Al/IP/CF/PA6 composite,which is determined by the properties of Al and Ti.When 10wt%Nano-CaCO3 is added,the bending strengths of Al/IP/CF/PA6 and Ti/IP/CF/PA6 are 339.1 MPa and 403.1 MPa,shear strengths are 46.9 MPa and 91.5MPa;and impact strength is 94.4kJ/m²,156.4kJ/m².Compared with Al/IP/CF/PA6,the bending,shear and impact strength of Ti/IP/CF/PA6increased by 18.9%,95.1%,and 65.7%,respectively.