Study On Thermal Deformation Behavior And Microstructure Of 0.5wt.%Graphene/Pure Aluminum

Ordinary aluminum alloys can no longer meet the needs of aerospace and other fields in terms of strength and thermal conductivity.The aluminum-based composite material has the advantages of high strength,high wear resistance,high thermal performance and good dimensional stability,which can better overcome these defects.Hot workability is one of the hot spots in the research of aluminum-based composite materials,and its research results can help to obtain aluminum-based composite materials with excellent performance.In this paper,0.5wt.%Graphene/Pure aluminum matrix(Gr/Al)composite material is taken as the research object,and the compression experiment is carried out using the Gleeble-3500 thermal simulation experimental machine,and the constitutive equation and heat Processing drawing.The microstructure characteristics under different thermal deformation parameters were studied;the appropriate extrusion parameters are selected to perform numerical simulation on the composite material,which provides theoretical support for the subsequent processing and production,and draws the following conclusions:(1)The true stress-strain curve of 0.5wt.%Gr/Al composite at a deformation temperature of 603K-723K and a strain rate of 0.01s-1-10s-1 shows that:when the deformation temperature is constant,As the strain rate increases,the flow stress of the composite will increase;when the strain rate is constant,as the deformation temperature increases,the flow stress of the composite will increase.(2)Three types of constitutive equations of 0.5wt.%Gr/Al composite material are obtained from the stress and strain data:The Modified JC model,The Modified ZA model,The Arrhenius constitutive model.(3)By constructing the hot working diagram of 0.5wt.%Gr/Al composite material,and characterizing the microstructure under different parameters of the hot working diagram.In the range of deformation temperature 603K-723K,strain rate 0.01s-1-10s-1,the best processing area of the composite material is analyzed:deformation temperature 703K-723K,strain rate 0.01s-1-0.1s-1.(4)The 0.5wt.%Gr/Al composite material was subjected to hot extrusion numerical simulation to analyze its stress distribution,load distribution,damage coefficient and temperature field.The analysis shows that the extrusion temperature of 470? and the extrusion speed of 1mm/min are the optimal extrusion parameters of the composite material.Combined with the microstructure of the extruded parts,it shows that under this parameter,the composite material undergoes dynamic recrystallization during hot extrusion.