Enhanced mechanical properties of rGO/Al composites via in-situ reduction and multi-pass rolling

Graphene, due to its unique mechanical properties, thermal conductivity and electrical conductivity, is considered as a reinforcement for metal materials. However, there are still issues with graphene aggregation and weak bonding at the graphene/metal interface. In this study, in-situ reduction techniques by nascent hydrogen was used to reduce graphene oxide (GO), and reduced graphene oxide (rGO) coated the Al powder to prepare composite powder. The composite powder was pre-shaped into blocks by hot-press sintering and the interface bonding issue of rGO/Al was improved by multi-pass rolling processes. Raman spectroscopy and XPS were used to analyze the reduction of GO. SEM, HRTEM and EBSD were used to analyze the composition, structure, and morphology of composites. The mechanical properties of the composite materials were studied. The results showed that GO was reduced to that almost all oxygen-containing groups were removed and uniformly dispersed in the Al matrix. The microstructure of the composites was dense, with good metallurgical bonding, and no apparent defects or porosity. When the loading amount is below 0.20 wt%, the ultimate tensile strength ( UTS ), yield strength ( YS ), and Young's modulus ( E ) were increasing along with the increased rGO content. When the addition amount was 0.20 wt%, UTS (147.67 MPa), YS (126.83 MPa), and E (36506.37 MPa), of the rGO/Al composites increased by 51.89 %, 37.87 %, and 94.48 %, compared to pure Al produced using the same process.