A review on strengthening mechanisms of carbon quantum dots-reinforced Cu-matrix nanocomposites

Combination of metal matrix materials with carbon quantum dots (CQDs) can not only optimize the property of metal matrix materials, but also produce novel material systems with ultra-high performance or superior comprehensive performance. The excellent electrical, mechanical, and thermal characteristics of CQDs can compensate for some intrinsic defects of the metal matrices to improve the composite properties. The various interfaces formed through the different degrees of CQDs dispersion in the metal matrices are essential in the mechanism of the composite performance improvement. In this review, the research progress and results of CQDs in metal matrix composites are discussed and summarized, including the recent preparation methods of CQDs and carbon nanostructure-reinforced metal matrix materials, as well as the influences of the preparation methods on the material structures and properties. In addition, by focusing on the interfaces between CQDs and metal matrices in composite materials, the performance improvement and reinforcement mechanisms of the CQD-modified metal matrix composites are described from mechanical, electrical, and thermal aspects. Further studies on CQDs in metal matrix composites are still required to provide theoretical guidance for the preparation of CQDs-reinforced metal matrix composites with intensity and ductility above the average.