Enhanced mechanical properties of GNPs/6061Al composites by Si atoms repairing the graphene defects: The first-principle calculation and experiment

Abstract

The mechanical properties of graphene are significantly affected by its in-plane holes defects. Studies have found that Si element was expected to spontaneously dope into the hole defects of graphene during the material processing process to increase the strength of graphene containing hole defects. First-principle calculated that when 2% and 10% Si doped into graphene, the strength was increased by 7% and 13% compared with graphene containing hole defects. In this paper, the Si atoms decomposed from PDMS at high temperature were used to realize the preparation of Si modified graphene/Al composites. Raman and XPS found that under the condition of long-term heat preservation at 600 °C, the content of hole defects in graphene decreased, and a new Si-C bond was produced. Under the joint action of graphene defect regulation and other strengthening mechanisms, the tensile strength of the composites has increased 9.4% from 338 MPa to 370 MPa, and the yield strength increased by 10.7%, while the plasticity did not decrease significantly. The performance improvement of the composites was due to the Si modification, which caused the strength of graphene to be improved compared with graphene containing holes.