Details

Autor(en) / Beteiligte

• Zhao, Lei
• Guo, Qiang
• Li, Zhiqiang
• Xiong, Ding-Bang
• Osovski, Shmuel
• Su, Yishi
• Zhang, Di

Titel

Strengthening and deformation mechanisms in nanolaminated graphene-Al composite micro-pillars affected by graphene in-plane sizes

Ist Teil von

• International journal of plasticity, 2019-05, Vol.116, p.265-279

Ort / Verlag

New York: Elsevier Ltd

Erscheinungsjahr

2019

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Graphene is considered to be an ideal reinforcement in metals, and its strengthening to the metal matrix is found to be the combined effect of load-sharing and the alteration of dislocation activity in the matrix. In this study, uniaxial compression tests were performed on graphene (reduced graphene oxide, RGO)-Al nanolaminated composite micro-pillars with different RGO in-plane sizes and laminate orientations. We elaborately controlled the processing parameters so that the composites with different RGO in-plane sizes shared the same RGO volume concentration and total RGO/Al interface area. It was found that the strength of RGO-Al composite pillars increased with decreasing RGO in-plane size, regardless of the laminate orientations relative to the loading direction (iso-strain or iso-stress). A clear transition in deformation mechanism existed in RGO-Al composite pillars having iso-strain configuration, from shear fracture in pillars with larger RGO in-plane size, to kink banding in pillars with smaller RGO nanosheets. These observations were interpreted by isotropic and kinematic hardening mechanisms, the superior constraining effect of smaller RGO nanosheets over dislocation transmission and motion, and the crack propagation in Al lamellae across the pillar interior. This work indicates that the mechanical behavior of graphene-reinforced metal matrix composites (MMCs) can be tailored by carefully tuning the geometry of the graphene nanosheets, without changing their type and concentration. [Display omitted] •Micro-compression tests were carried on graphene-Al pillars with various graphene in-plane sizes and laminate orientations.•The mechanical mechanisms of graphene-Al pillars were evaluated from loading-unloading cycles and microstructural analyses.•A 3 folds' reduction in the graphene size conferred an over 15% increase in the strength, and a different deformation mode.•The stronger isotropic and kinematic hardenings led to the higher strength of graphene-Al pillars.•The superior constraining effect of smaller graphene size led to the deformation kinking of graphene-Al pillars.