Study On Microstructure,Properties And Strengthening Mechanism Of GNPs/Cu Composites Prepared By Powder Metallurgy Method

In recent years,with the rapid growth of China's economy and the rapid development of the Internet of Things and cloud computing,we have ushered in a new trend of global informatization.Subsequently,in the application field of electronic packaging,the requirements for the power of the chip have gradually increased.Therefore,in order to meet the requirements of the use of electronic packaging,the thermal conductivity and mechanical performance standards of the packaging materials have also been improved.However,a single traditional metal material has been difficult to meet the packaging requirements of high-power chips.Therefore,researchers began to add some kind of reinforcement to make the obtained composite material,while retaining the excellent performance of copper metal,as much as possible.May improve the mechanical properties of the material.At present,some people improve its performance by adding diamond as a reinforcement.Although the electrical and thermal conductivity have been significantly improved,due to the large hardness of diamond,it cannot be machined,which limits its wide application.Therefore,in this paper,the two-dimensional carbon material graphene with high electrical conductivity,high thermal conductivity,and excellent mechanical properties is used as the reinforcement,and pure copper metal is used as the matrix.The ball milling process,the spark plasma sintering process,and the rolling optimization process are used to prepare the thermodynamics,Graphene/copper composite materials requiring electrical and mechanical properties.This article first studied the preparation process of the composite powder.First,perform flake ball milling treatment on the original copper powder,and finally determine that when the ball milling speed is 300r/min,the ball-to-battery ratio is 10:1,the grinding aid ratio is 2:1(anhydrous ethanol),and the ball milling time is 2h,the copper The powder ball mill has the best flake effect.The copper powder particle size range is increased from 1?3?m to 15?50?m,the average particle size is 35.31?m,and the thickness is 50?500nm;then the graphene is mixed with the obtained copper flakes In the ball milling treatment,when the ball milling speed is 200r/min,the ball milling time is 2h,and absolute ethanol is used as the grinding aid,the obtained composite powder has no oxidation phenomenon and the graphene dispersion is relatively uniform.Furthermore,the preparation process of composite materials was studied,and the influence of SPS sintering process parameters on the density,density,electrical conductivity,thermal conductivity,hardness and other properties of the prepared composite materials was explored.After research,when the sintering temperature is1020?,the sintering pressure is 40MPa,the sintering time is 10min,and the pulse current is 2/1/10,the prepared composite material has a smooth surface without obvious defects,a high density of 8.58g/cm~3,and compactness.It reaches 97.2%,the thermal conductivity is 379.8J/(m·?),the electrical conductivity is 83.7IACS%,and the Vickers hardness is 87.3HV.Subsequently,the evolution of graphene in the composite material during the rolling deformation process was systematically studied.Analyzing the experimental data,after research:1.As the rolling temperature increases,the graphene layer thinning effect gradually decreases,and the number of defects also decreases.When the rolling temperature is 20?,the graphene thins to About 1 layer,when the rolling temperature is 700?,the number of graphene layers is between 2 and 5 layers;2.As the rolling reduction increases,the graphene thinning effect increases.When the reduction amount is 3%,the number of graphene layers in the composite material is about 5 layers,when the rolling reduction amount is 10%,the number of graphene layers in the composite material is about 2 layers;3.With the increase of the total deformation,the number of graphene layers is also decreasing,from about 10 layers of the original composite material to between 2 and 5 layers.Finally,the thermal conductivity,electrical conductivity and mechanical properties of the optimized composite material are studied.Conclusions are obtained:1.As the rolling temperature increases,the hardness of the composite material increases less,but at the same time the conductivity of the composite material improves more.When the rolling temperature is 20?,the hardness of the composite material can reach the maximum 132.4HV,compared with the original composite material increased by 51.7%,the conductivity increased to 89.7IACS%,an increase of 7.2%;when the rolling temperature is 700?,the hardness of the composite material increased to 113.8HV,which is higher than the original composite material 30.4%,the electrical conductivity increased to 95.2IACS%,an increase of 13.7%;2.With the increase in the reduction of each pass,the maximum hardness of the composite material increased from 103.2HV to126.6HV;But when the reduction amount per pass is 5%,the conductivity of the composite material is relatively good,increasing to 95.2IACS%;3.When the rolling temperature is 700?,when the reduction amount is 80%,the performance is the best Well,the hardness and electrical conductivity have reached the maximum values??of 113.8HV and 95.2IACS%respectively.