Effect Of Hot Rolling Process On Interfacial Microstructure And Thermal Conductivity Of Graphene Reinforced Steel Aluminum Matrix Composites

In this study,graphene reinforced stainless steel/aluminum/stainless steel composites were prepared using the hot rolling process,and then subjected to annealing treatment to prepare composites with good interfacial adhesion and high thermal conductivity.The interfacial microstructure of the composite was systematically characterized using metallographic microscopy,scanning electron microscopy,and energy dispersive spectroscopy;The thermal conductivity and mechanical properties of graphene reinforced stainless steel/aluminum/stainless steel were studied using a thermal conductivity tester and a tensile machine.The relationship between the preparation process,interface structure,and performance was established,providing theoretical and practical guidance for the design of stainless steel/aluminum/stainless steel composites with excellent performance.The interface conditions of immortal steel/aluminum/stainless steel composites prepared under different rolling processes were investigated.The results showed that composites with excellent bonding interfaces were prepared at 450°C,a reduction ratio of 40%,and a rolling speed of 0.2 m/s;Based on this rolling process,graphene reinforced composites with interfaces of 0.006mg/mm~2 and 0.01mg/mm~2 were prepared;No obvious intermetallic compounds were found at the stainless steel/aluminum interface during heat treatment of the composite at a rolling temperature between 300°C and 450°C;When the heat treatment temperature reaches500°C,intermetallic compounds appear at the stainless steel/aluminum interface,mainly Fe2Al5,Fe Al3,and Al Fe O3,and the thickness increases with the increase of annealing time;Compared to pure stainless steel/aluminum/stainless steel composite materials,the intermetallic compounds at the interface of graphene reinforced stainless steel/aluminum/stainless steel composite materials are discontinuous,which is due to the fact that graphene hinders the mutual diffusion of atoms such as Fe and Al at the interface and hinders the formation of compounds.The test results of mechanical and thermal conductivity show that when the annealing temperature is lower than 500°C,the thermal conductivity of all composites increases with the increase of annealing temperature,which is caused by the diffusion of the interface and the realization of metallurgical bonding;When the heat treatment temperature is increased to500°C,the thermal conductivity of all stainless steel/aluminum/stainless steel composites decreases,but graphene reinforced stainless steel/aluminum/stainless steel composites are superior to pure stainless steel/aluminum/stainless steel composites.This is mainly due to:(1)graphene inhibits the occurrence of intermetallic compounds at the stainless steel/aluminum composite interface,and(2)graphene from the stainless steel/aluminum interface provides a high-speed transmission channel for heat conduction.The interfacial bonding strength of the composite increases with the increase of rolling temperature,and first increases and then decreases with the increase of annealing temperature.When the annealing temperature is 500°C for 2h,the interfacial bonding strength reaches the maximum value.After adding graphene,the interfacial bonding strength of the composite decreased,mainly due to the influence of graphene at the interface on the interfacial bonding strength.