The role of interfacial states in governing the mechanical behavior of graphene-reinforced aluminum (Gr/Al) composites remains insufficiently understood due to the difficulty of precisely controlling these states and preserving structural integrity prior to testing. In this study, structurally well-defined Gr/Al composites, with uniform density, grain size, and Gr spatial distribution, were fabricated via heteroagglomeration and spark plasma sintering (SPS), enabling discrete evaluation of interfacial states. Transmission electron microscopy revealed that the surface Al oxide layer fractured at 863 K; at 883 K, the Al 4 C 3 phase nucleated and extended into Al grains, fully transforming into nanorods at 903 K. While tensile strength at room temperature was unaffected by sintering temperature, at 523 K it first increased and then decreased with rising SPS temperature. These findings resolve long-standing uncertainties in Gr–metal interactions and provided a pathway to overcoming weak bonding and high-temperature degradation in nanocarbon-reinforced metals.
Zhou et al. (Sun,) studied this question.