Research On Friction And Wear And Cutting Performance Of Graphene /Al-Si Composites

In recent years,with the industrial development and technological advances,Aluminum matrix composites(AMCs)have been widely used in aerospace industry,automobile parts,electronic packaging,which has high strength,low density,high wear resistance,good dimensional stability and low thermal expansion coefficien.Graphene is a new material with excellent performance,which has high strength and elastic modulus.It is one of the material with highest conductivity,thermal conductivity in the world,known as the king of new material.If they are combined with other elements,such as Si,Cu and Mg,they will become a new type of metal matrix composites with high performance--graphene/aluminum silicon(Gr/Al-Si)composite materials.Due to the addition of graphene and Si,Cu,Mg and other elements,the material has many problems such as graphene dispersion,particle size distribution and morphology of silicon inter-metallic compound size,which is easy to cause vibration of the tool and decrease in surface quality in cutting.These problems influence the cutting performance of the composite material and limit the range of its applications in industry.In this paper,Gr/Al-18Si composites are prepared by powder metallurgy.The influence of graphene on the microstructure of Gr/Al-18Si composites was studied by means of optical microscope and X ray diffractometer.The results show that the addition of graphene can effectively refine the silicon particles,and the inter-metallic compounds Al2Cu and Mg2Si are more closely distributed along the grain boundaries.The mechanical properties and physical properties of Gr/Al-18Si composites were tested,and the influence of the amount of graphene addition on the macro mechanical properties was discussed.The friction and wear properties of Gr/Al-18Si composites with different graphene content were discussed by reciprocating friction and wear test.By changing the content of graphene,the friction coefficient curves with time of Gr/Al-18Si composites were obtained.The quality of composites before and after wear test was measured,and the wear loss was calculated.The effect of graphene content on the wear resistance of composites was studied.The SEM diagram of wear surface of Gr/Al-18Si composites was obtained by scanning electron microscopy,and the wear mechanism of Gr/Al-18Si composites with different graphene content was studied.By calculating the box-counting dimension of wear surface of Gr/Al-18Si composite material with different graphene content,In cutting characteristics of material,the three-dimensional finite element simulation model of Gr/Al-18Si composites with different graphene content was established,milling process of materials under different cutting parameters was simulated.The effects of different graphene content and cutting parameters on the main cutting force F_x and chip morphology were analyzed.The milling process of Gr/Al-18Si composites was tested and verified by comparing the experimental results with the simulation results.The empirical formula of Gr/Al-18Si cutting force was established by using multiple regression analysis method,and the significance of the model was tested.The cutting force under different parameters was predicted by using the formula,and the predicted results were compared with the measured results.At the same time,the BP neural network prediction model of cutting force of Gr/Al-18Si composites was established.The accuracy of the two prediction model of cutting force was compared,and the optimal model of cutting force prediction was determined.