The bonding strength of a Gr/Mg
2Si interface was calculated by first principles. Graphene can form a stable, completely coherent interface with Mg
2Si. When the (0001)
Gr/(001)
Mg2Si crystal plane is combined, the mismatch degree is 5.394%,
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The bonding strength of a Gr/Mg
2Si interface was calculated by first principles. Graphene can form a stable, completely coherent interface with Mg
2Si. When the (0001)
Gr/(001)
Mg2Si crystal plane is combined, the mismatch degree is 5.394%, which conforms to the two-dimensional lattice mismatch theory. At the interface between Gr/Mg
2Si, chemical bonds were not formed, there was only a strong van der Waals force; the interfaces composed of three low index surfaces (001), (011) and (111) of Mg
2Si and Gr (0001) have smaller interfacial adhesion work and larger interfacial energy, the interfacial energy of Gr/Mg
2Si is much larger than that of α-Al/Al melt and Gr/Al interfacial (0.15 J/m
2, 0.16 J/m
2), and the interface distance of a stable interface is larger than the bond length of a chemical bond. The interface charge density difference diagram and density of states curve show that there is only strong van der Waals force in a Gr/Mg
2Si interface. Therefore, when the Gr/AlSi10Mg composite is stressed and deformed, the Gr/Mg
2Si interface in the composite is easy to separate and become the crack propagation source. The Gr/Mg
2Si interface should be avoided in the preparation of Gr/AlSi10Mg composite.
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