▎ 摘　　要

In this paper, a successful attempt was demonstrated to prepare graphene reinforced aluminum matrix composites by in situ exfoliation of graphite flakes (GFs) using rotational friction extrusion (RFE) method. It is found that the GFs are broken on a large scale and uniformly dispersed into the aluminum matrix during PRE. EBSD analysis indicates that the grain is significantly refined, the fraction of high angle grain boundaries is increased. As revealed by HRTEM that a number of 5 similar to 12 layer graphene can be peeled off from the GFs owing to the severe plastic deformation of RFE, and there exists obvious transition at the graphene-aluminum interface due to the diffusion of carbon atom at the broken graphene edge, which provides an efficient load transfer for the composites. The yield strength and ultimate tensile strength of the prepared composites with GFs addition of 0.82wt% are 76.4 and 163.2 MPa, which are 91% and 71.4% higher than those of the RFEed base metal (1060 Al), respectively. Meanwhile, the elongation of the composites is 25.3%, and a good strength-ductility balance is obtained. Combined with theoretical calculations, it is found that the main strengthening contribution is most likely attributed to the load transfer and Hall-Petch mechanism.