Effects of hot extrusion on the microstructure and mechanical properties of 2024Al-GNPs composites

Abstract

Effects of hot extrusion on the microstructure and mechanical properties of 2024Al-0.8GNPs (graphene nanoplates) composites were evaluated. Results showed that the microstructure and mechanical properties of 2024Al-0.8GNPs composites gradually improved with increasing extrusion ratio in a given range of extrusion ratios. At an extrusion ratio of 16, the most noticeable improvement in the microstructure and mechanical properties of the composites were obtained. The tensile strength, yield strength, elongation, and microhardness reached 345.8 MPa, 246.7 MPa, 13.5 %, and 181.6 HV, respectively, which were 90.5 %, 91.7 %, 150.0 %, and 95.3 % higher compared to the as-cast matrix alloy. And the composites exhibited typical ductile fracture characteristics. The dual effects of high-energy ultrasound and hot extrusion improved the interface between GNPs and the Al matrix. The effect of good interfacial structure and good dispersion induced the GNPs in composites to effectively exert thermal residual gravitational strengthening, load transfer strengthening, Orowan strengthening, and fine grain strengthening. • The dual effects of high-energy ultrasound and hot extrusion improved the interface between GNPs and the Al matrix. • At an extrusion ratio of 16, the microstructure was effectively improved and there were obvious textures in the <001> and <111> crystal directions. • Under the optimum extrusion ratio, the tensile strength, yield strength, elongation of 2024Al-0.8GNPs composites reached 345.8 MPa, 246.7 MPa and 13.5%, respectively.