Effect of Graphene on Interfacial Microstructure and Thermal Conductivity of Stainless Steel/Aluminum Composites

Graphene-enhanced stainless steel/aluminium/stainless steel composites were prepared by hot rolling technique,and the interfacial microstructures after annealing treatment were investigated and the thermal conductivity enhancement mechanism was revealed. The results show that the stainless steel/aluminium interface (without graphene addition) after annealing at 400 ℃achieves metallurgical bonding without obvious intermetallic compound diffusion layer;after annealing at 500 ℃for 2 h,the stainless steel/aluminium composite interface generates continuous intermetallic compounds,and its thickness increases with the increase of annealing time and temperature. When the graphene is added to the stainless steel/aluminium interface,discontinuous intermetallic compounds appear at the interface after annealing at 500 ℃for 4 h. With the increase of graphene concentration,the amount of intermetallic compounds formed at the stainless steel/aluminium interface decreases significantly. The thermal conductivity of the stainless steel/aluminium/stainless steel composites increases with the increase of the annealing time when annealed at 400 ℃,and it increases firstly then decreases with the increase of the annealing time when annealed at 500 ℃. Graphene hinders the formation of interfacial intermetallic compounds and provides a high-speed channel for heat transfer,and the thermal conductivity of the samples with graphene addition is always higher than that of the samples without graphene addition.