Increased electromagnetic interference shielding and load bearing with a three-dimensional pristine graphene@pyrocarbon skeleton in AZ91D

The development of electronic devices for communication systems, radar warning, and satellite detection requires lightweight materials that exhibit exceptional electromagnetic interference (EMI) shielding while maintaining mechanical robustness. However, designing three-dimensional (3D) structured pristine graphene (PG) that achieves both high EMI shielding and substantial load-bearing capacity remains a significant challenge. In this work, an innovative method of 3D skeleton preconstruction-infiltration filling is proposed. This approach demonstrates that molten AZ91D is infiltrated into the 3D structured PG@pyrocarbon (PG@PyC), and its 3D structure can be maintained in the AZ91D matrix via a liquid-solid infiltration extrusion method. By utilizing this strategy, PG@PyC reinforced AZ91D matrix (PG@PyC/AZ91D) composites display remarkable comprehensive performance, realizing an EMI shielding effectiveness of 76.70 dB (at 3 mm thickness), ultimate compressive strength of 276 MPa, and ultimate tensile strength of 231 MPa. The developed composites are promising lightweight materials for the integration of structural and functional applications in complex environments. This work proposes an innovative method of 3D skeleton preconstruction-infiltration filling to construct a 3D pristine graphene@pyrocarbon skeleton in AZ91D, improving electromagnetic interference shielding and load bearing of the composites.