▎ 摘　　要

It has not been reported in the existed literatures that whether it is possible to prepare GNFs/Al composites by pressure infiltration method due to the poor wettability and severe reaction behavior between carbon and molten Al. In the present study, microstructure and mechanical behavior of graphene nanoflakes (GNFs) reinforced Al-20Si (GNFs/Al-20Si) composites prepared by the pressure infiltration method have been thoroughly investigated. The Al-20Si matrix was chosen to inhibit the formation of Al4C3. It has found that the GNFs and Al alloy matrix has been well bonded without formation of Al4C3, which authenticated the effectiveness of the alloying treatment. Moreover, the hardness and the elastic modulus of the composites were increased linearly with the increase in the GNFs content. After addition of 1.5 wt% GNFs, the ultimate tensile strength and bending strength attained the peak values, which increased 130% and 230% to that of Al matrix, respectively. To the best of our knowledge, it is the highest strengthening ratio in Al matrix composites reinforced with graphene reinforcements. Furthermore, based on the modified shear-lag model and combined with the literatures' data, the strengthening behavior of GNFs/Al composites has been extensively discussed. It is concluded that the pressure infiltration method is the most feasible and successful way to prepare GNFs/Al composites without formation of Al4C3 and with high strengthening ratio.