Research On Calculation Of The Interface Structure And Mechanical Properties Of Graphene/Aluminum Composites

Graphene is the strongest material measured so far,and has many advantages as a reinforcement.However,the existence of graphene defects leads to a large gap between their actual performance and theoretical performance,and repairing graphene defects through certain means plays a vital role.This subject uses the first-principles method tcalculated the effects of graphene vacancies and Si atom repair graphene vacancies on the graphene/Al composite interface.Graphene/Al composites were prepared by pressure infiltration,and the effects of Si-based and C-based process control agents on the microstructure and mechanical properties of graphene/Al composites were investigated.The introduction of graphene vacancies leads to the formation of C-Al bonds at the graphene/Al composite interface.As the number of graphene vacancies increases,the theoretical value of the graphene/Al interface spacing decreases from 4.3 ? to 2.9 ?;the C-Al bond formed near the vacancy is stronger;the theoretical value of the interface adhesion work increases in sequence,and the interface bonding performance becomes better and better;the theoretical value of the interface energy decreases in sequence,and the interface becomes more and more stable.As the graphene vacancy tightness increases,the theoretical value of the graphene/Al interface spacing increases from 2.9 ? to 3.3 ?;the number of electrons acquired by C atoms near the vacancies at the interface and the number of electrons lost by Al atoms increase first and then decrease,and the C-Al bond formed near the vacancies first becomes stronger and then weaker;the theoretical value of the interface adhesion work decreases in turn,and the interface bonding performance becomes worse;the theoretical value of the interface energy increases,the interface Becomes unstable.After repairing graphene vacancies with Si atoms,Si atoms have a tendency to dissolve into the Al matrix,and Si atoms shift significantly in the direction of Al,forming Si-Al bonds at the interface.As the number of Si atoms repairing the vacancies of graphene increases,the theoretical value of the graphene/Al interface spacing decreases from 4.0 ? to 3.7 ?;the Si-Al bond formed at the interface becomes stronger;the theoretical value of the interface adhesion work increases,and the interface bonding performance becomes better and better;the theoretical value of the interface energy decreases first and then increases,and the interface becomes relatively stable first and then becomes unstable.As the vacancy tightness of Si atoms repairing graphene increases,the theoretical value of the graphene/Al interface spacing increases from 3.7 ? to 3.9 ? and then decreases to 3.7 ?;The number of lost electrons of Si atoms decreases first and then increases,The obtained electrons of Al atoms nearby Si atoms decrease,and there is no obvious tendency for the bonding strength between Si atoms and Al atoms.The theoretical value of the interface adhesion work increases first and then remains unchanged,and the interface bonding performance becomes better.When the tightness reaches a certain value,the interface bonding performance reaches a stable state;the interface energy theoretical value decreases first and then increases,and the interface changes relatively stable first.When the tightness of repaired Si atoms exceeds a certain value,the interface becomes unstable.With dimethyl silicone oil as the process control agent,the Al powder flakes obviously after ball milling.The effect of dimethyl silicone oil viscosity on the graphene defects in the mixed powder after ball milling has no obvious trend.After the modification of graphene by dimethyl silicone oil,the sp3/sp2 value in the graphene structure drops from 0.69 to 0.37,graphene defects were reduced.At the same time,C-Si appears in the graphene structure.The composite material after solution aging treatment,the composite material modified with 350 c St dimethyl silicone oil has the highest strength;the composite material modified with 10 c St dimethyl silicone oil has higher plasticity and has better comprehensive mechanical properties.After annealing treatment,the composite material modified with 100 c St silicone oil has the best plasticity,but the strength is lower;the composite material modified with 10 c St silicone oil has the highest strength,but the plasticity is poor.When organic matter is used as the material of the process control agent,the cold welding phenomenon occurs in the ball milled Al powder.The defects of graphene after modified by different C-based process control agents vary greatly.The hardness of the composites prepared with organics as a process control agent is significantly improved.