Enhanced mechanical properties of Al5083 alloy with graphene nanoplates prepared by ball milling and hot extrusion

Graphene is considered as an excellent reinforcement due to its excellent physical and mechanical properties. In this work, milling balls of small diameter were used to reduce the collision energy during the ball milling process, and graphene nanoplates (GNP) reinforced Al5083 alloy matrix composites were successfully fabricated by ball milling, hot pressing and hot extrusion. The microstructures of the ball-milled powders and GNP/Al5083 composites were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The results showed that the GNP could remain after ball milling. However, the Al₄C₃ phase was found in bulk GNP/Al5083 composites, suggesting that some of the GNP reacted with Al and formed Al₄C₃ during the consolidation process. Tensile tests revealed that both the yield strength and ultimate tensile strength of the 1.0 wt.%GNP/Al5083 composite were increased by 50% compared with pure Al5083 fabricated under the same procedure. The relevant strengthening mechanisms of the composites were discussed.