▎ 摘　　要

The lamellar and orientational characteristics of graphene nanoplatelets (GNPs) are crucial for reinforcing metal matrix composites, particularly in terms of their thermal properties. Two kinds of GNPs with plane sizes of 6 & mu;m and 80 & mu;m were respectively used as reinforcements in ZK60 alloy by powder metallurgy. The oriented distribution of GNPs in the matrix was obtained using a double-pass hot extrusion process, i.e., a stepped extrusion with two consecutive extrusion ratios (10:1 and 16:1). Reinforced with 0.05 wt% oriented GNPs (80 & mu;m), the composite exhibited a tensile yield strength of 257 MPa, ultimate tensile strength of 342 MPa, elongation of 24.7%, and notably enhanced thermal conductivity of 128.3 W (mK)(-1) even with refined grain size compared to the ZK60 alloy. The oriented GNPs in the matrix create a favorable path for efficient load and heat transfer, leading to the simultaneously enhancement of mechanical and thermal properties of the GNPs/ZK60 composites. This work is expected to broaden the application potential of GNPs as highly efficient reinforcements and provide a practical method for fabricating metal matrix composites.