Towards strength-ductility synergy with favorable strengthening effect through the formation of a quasi-continuous graphene nanosheets coated Ni structure in aluminum matrix composite

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 748; pp. 52 - 58
• Main Authors: Liu, Xinghai, Li, Jiajun, Liu, Enzuo, He, Chunnian, Shi, Chunsheng, Zhao, Naiqin
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 04.03.2019; Elsevier BV
• Subjects: Aluminum; Aluminum base alloys; Aluminum matrix composites; Coating effects; Continuous coating; Deformation effects; Deformation mechanisms; Dislocations; Ductility; Elongation; Grain refinement; Graphene; Graphene nanosheets; Interfacial bonding; Load transfer; Mechanical properties; Microstructure; Nanosheets; Nickel; Strengthening mechanism; Thermal expansion; Thermal mismatch; Wettability; Aluminum matrix composites; Mechanical properties; Graphene nanosheets; Microstructure; Strengthening mechanism
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2019.01.046

In this study, in situ synthesis of graphene nanosheets (GNS) coated nickel (Ni@GNS) as reinforcement for aluminum matrix composites (Ni@GNS/Al) was reported. Ni@GNS exhibits a quasi-continuous network-like structure. The addition of Ni could reduce the interfacial thermal expansion and improve the wettability between GNS and Al, resulting in a robust interfacial bonding among GNS, Ni and Al. Due to the unique structure, the composite exhibits a favorable strength-ductility synergy. The yield strength of the composite increases to 237 ± 2 MPa, ~ 80.9% improvement compared to that of the unreinforced Al, combined with an excellent elongation of 19.1 ± 2%. The main strengthening mechanisms are the interfacial thermal mismatch and Orowan dislocation strengthening, with some contributions of grain refinement, load transfer of GNS and precipitated-phase strengthening of Ni. Moreover, the interlocked effect between GNS and Ni could further prolong the deformation failure and improve the plasticity of the composites.