Study on low temperature creep properties of Al8030 composites added by directional distribution of graphene nanoplatelets

The Al8030 composites added by graphene nanoplatelets (GNPs) with the mass fraction of 0.5% were prepared by powder modification and semi-solid extrusion process, and the effects of GNPs on the microstructure and low temperature creep properties of aluminum matrix composites were investigated. The results show that, the GNPs are mainly distributed on the grain boundary of composites and show the directional distribution characteristics as parallel to the extrusion direction. The steady-state creep rate of the composite samples in the service conditions decreases by more than 50% compared to that of the matrix. In the experimental conditions of 90 ℃ and 50~90 MPa, the creep mechanism of the matrix is dominated by the dislocation climbing mechanism, while the creep of the composites is affected by the dislocation slip and dislocation climbing. In the experimental conditions of 120~150 ℃ and 50~90 MPa, the creep mechanism of the matrix and composites are controlled by the dislocation climbing and the second phase enhancement, but the addition of GNPs makes the control effect of the second phase enhancement on creep more obvious.