In-situ architecturing of 3D graphene networks in metals via laser additive manufacturing for strength-toughness synergy.

Integrating two-dimensional nanomaterials into three-dimensional bulk metals to simultaneously achieve high strength and toughness remains challenging. Conventional fabrication methods for graphene-reinforced metal matrix composites (MMCs) often lead to graphene layers agglomeration and poor interfacial bonding. Here, we report a transformative manufacturing strategy that spontaneously architectures a three-dimensional graphene network within the metal matrix. Exploiting the rapid thermal cycles of laser powder bed fusion with a Ni/polymer precursor system, we drive in-situ conformal growth of high-quality graphene wrapping printed Ni scaffolds. Subsequent hot pressing densifies the pre-designed structure into a bulk composite, preserving the continuous, three-dimensional graphene network. This architectured composite exhibits a pronounced strength-ductility synergy, achieving a 72% enhancement in ultimate tensile strength (648 MPa) without sacrificing ductility (54% elongation). Our approach shifts additive manufacturing from a shaping technique to a potent platform for precise reinforcement architecture control, establishing a viable route to fabricate high-performance MMCs.