Influence of interfacial configuration on bonding properties and thermal conductivity of heterogeneous interface in Al/Graphite composite used for electronic packaging

Abstract

With the purpose of improving the service performance of aluminum(Al)/graphite(Gr) composites used for electronic packaging, the density functional theory (DFT) calculations were employed to investigate the influence of the interfacial configuration on the bonding properties and thermal conductivity of Al/Gr heterogeneous interface. The Al(111)/Gr(0001) interfaces with the low mismatch (0.569%) were first constructed by lattice transformation, and two different interfacial configurations of Top and Bridge were determined. The calculated results indicate that, the interfacial bonding properties of Al(111)/Gr(0001) interfaces are determined by interfacial Al–C bonding behavior. Although the covalent characteristics of Al–C bonds are similar for the two configurations, the ionic characteristics for Top configuration are significantly stronger than Bridge configuration. Therefore, the Top configuration has not only a greater bonding strength than Bridge configuration manifested as the larger interfacial work of adhesion for 0.323 J/m2 and ideal tensile strength of 1.47Gpa, but also the better plasticity with the sustainable maximum strain of 10.46%. Moreover, the thermal conductivity of Top configuration is higher than that of Bridge configuration and the maximum values of the two configurations are 4.90 and 3.75×10−2·W·m−1·k−1, respectively. The mechanism for the favorable thermal transport properties of Top configuration compared to Bridge configuration lies in the high electron density and the large degree of electron delocalization at the interface. Therefore, the Top configuration is the promising Al(111)/Gr(0001) interfacial configuration, which can significantly improve the bonding properties and thermal conductivity of the Al/Gr composite.