Enhanced interfacial bonding and mechanical properties of CeO2-coated graphene oxide reinforced 7075 composites

Abstract

Severe interfacial reactions and interfacial bonding between graphene and Al matrix have been the main challenges to achieve high performance graphene reinforced aluminum matrix composites (AMCs). In this study, a new interfacial structure design was proposed to address the above challenges by coating CeO2 nanoparticles on the surface of graphene oxide (GO). Then, CeO2-coated GO reinforced 7075 (GO/7075) composites were successfully fabricated via ultrasonic assisted casting. It was found that the coated CeO2 on GO could react with Al matrix to form Al11Ce3 and suppress the formation of interfacial product Al4C3. Additionally, the as-formed Al11Ce3 at the interface served as a bridge to tightly bind the GO and Al, thus resulting in forming a strong interfacial bonding, which was favour to the load transfer. Moreover, when adding 1.5 wt% CeO2-coated GO, the average grain size of the composites reduced from 100.8 μm to 38.5 μm. As a result, the composite reinforced with 1.5 wt% CeO2-coated GO demonstrated enhanced mechanical properties with a yield strength of 263.4 MPa and an ultimate tensile strength of 342.8 MPa, 100.8% and 69.4% higher than those of unreinforced 7075 alloy, respectively. Furthermore, the strengthening mechanisms of CeO2-coated GO/7075 composites were discussed in detail.