Molding And Properties Study On Tensile And Friction Of Carbon Fiber Forged Composites

Carbon fiber forging composite(CFFC)is a novel material,gradually applied by Boeing Company and Lamborghini Company.It has an advantages of excellent process compatibility,light weight,high overall performance and low cost,with broad prospects for application and popularization of the main load-bearing structural components to the aerospace,transportation and high-end equipment.However,the manufacture and application of carbon fiber forging composite materials is in lack of theoretical and technical support.In this paper,the rapid prototyping process of the epoxy resin-based forged composites is studied as the optimization goal.Three impotant perforrmances of CFFC-tensile strength,dry friction properties,water lubricated friction properties are researched to optimize process parameters.First,the influence of molding parameters and material structure parameters on CFFC was discussed.The random tension test is used to study the influence of different molding parameters and structural parameters on the mechanical properties of CFFC.Tensile strength is taken as the main evaluation criteria to evaluate the influence on the tensile properties of CFFC with molding pressure P,compression temperature Tp,curing temperature Tc and curing time t,as well as carbon fiber length L and fiber type M.The fracture morphology of CFFC is observed by scanning electron microscopy(SEM).The results show that the tensile strength of CFFC is mainly determined by the bonding quality of the carbon fiber/resin interface.Three different types of fracture occur depending on the bonding quality: fiber pull-out,resin fracture and cohesive failure.Cohesive failure is the ideal form of failure,at which composites have the highest tensile strength.Secondly,the friction performances of CFFC under two different service conditions(dry friction and water lubrication)are studied.The friction coefficient and wear rate are taken as the objective to analyze the influence of molding parameters and structure parameters on the friction performance of CFFC;the frictional properties of CFFC under different lubrication conditions,different frictional loads and relative velocities are studied;the main wear forms and mechanisms of CFFC are revealed by observing the microstructure of the wear surface.It id found that abrasive wear and adhesive wear are two main forms of wear modes;the transfer film and the water-lubricated film have a strong boundary lubrication effect,which is beneficial to reduce the friction coefficient of CFFC.Considering the optimal tensile and tribological properties,the optimal parameters are P=10 MPa,Tp=110 ?C,Tc=140 ?C,t=30 min,L=50 mm and M is Toray T700 SC.The normalized tensile strength,dry friction coefficient and water-lubricated friction coefficient of the optimized forged composite is 331 MPa,0.080 and 0.045 respectively.