Enhancing strength-ductility synergy of carbon nanotube/7055Al composite via a texture design by hot-rolling
04 Mar 2021-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing (Elsevier)-Vol. 806, pp 140830
TL;DR: In this paper, texture optimization through hot-rolling was employed to improve the strength-ductility of the CNT/7055Al composites, which is an urgent problem to be solved.
Abstract: The limited ductility of carbon nanotubes reinforced Al matrix (CNT/Al) composites hinders their engineering applications, which is an urgent problem to be solved. Herein, texture optimization through hot-rolling was employed to improve the strength-ductility of the CNT/7055Al composites. Microstructural examinations indicate that the composite subjected to extrusion (CNT/7055Al-E) had a bimodal structure with the coarse and ultrafine grains. The composite subjected to extrusion followed by hot-rolling (CNT/7055Al-ER) exhibited a uniform ultrafine grain structure. No further structure damage or aggregation was detected for the CNTs after hot-rolling. The texture analysis demonstrates that the CNT/7055Al-E had a fiber texture, while the CNT/7055Al-ER had a plate texture including {011} , {113} and {215} components with higher texture intensity. Compared with the CNT/7055Al-E, the CNT/7055Al-ER increased twofold in elongation with a slight decrease in strength, which was attributed to the favorable grain orientations, the increased proportion of low angle grain boundaries, as well as the fine and densely distributed precipitates. Further, the mechanical property anisotropy of the composite was weakened after hot-rolling due to the elimination of coarse grain bands.
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TL;DR: In this paper, the authors report the prominent strengthening efficiency in graphene nanosheet reinforced Al matrix composites fabricated via hybrid deformation combining hot extrusion and multi-pass hot rolling (MPHR).
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TL;DR: In this article, two heterogeneous CNT/2009Al composites with coarse grain (CG, 2μm) DZs or ultra-fine grain (UFG, ~500 nm)DZs were fabricated and achieved enhanced strength-ductility.
Abstract: Heterogeneous structure consisting of brittle-zones (BZs) rich of carbon nanotubes (CNTs) and ductile-zones (DZs) free of CNTs, was an effective way to improve the strength-ductility of CNT reinforced Al (CNT/Al) composites. Two heterogeneous CNT/2009Al composites with coarse grain (CG, ~2 μm) DZs or ultra-fine grain (UFG, ~500 nm) DZs were fabricated and achieved enhanced strength-ductility. However, the heterogeneous composite with CG DZs had a lower high-cycle fatigue strength as well as fatigue strength/tensile strength ratio than the uniform composite, while the heterogeneous composite with UFG DZs exhibited the increased fatigue strength and the same level of fatigue strength/tensile strength ratio compared to the uniform composite. It was found that the improved fatigue properties for the heterogeneous composite with the UFG DZs could attribute to two reasons. Firstly, the UFG for the DZs significantly increased the strength of DZs, which effectively reduced the strain localization in the DZs. Secondly, the dislocations piling up at the grain boundaries of the BZs, as well as the stress concentration at the boundaries between the DZs and BZs were relieved due to the coordinated micro-strain for the heterogeneous structure. This provided a simple strategy for the structural design of heterogeneous composites with high fatigue strength.
13 citations
TL;DR: In this paper, the tension-tension/tension-compression fatigue behaviors of bimodal structure CNT/7055Al composites consisting of ultra-fine grain (UFG) zones rich of CNTs and coarse grain (CG) bands free of carbon nanotube (CNTs) were investigated and the corresponding damage mechanisms were analyzed.
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TL;DR: In this article , the influence of hot rolling on the microstructure, mechanical properties, anisotropy and interfacial conditions of the B 4 C/Al composites were systematically investigated.
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TL;DR: In this paper , a review of the relevant literature concerning the simulation of graphene/metal composites and their mechanical properties is presented, showing that computer simulation is a possible and practical way to understand the effect of the morphology of graphene reinforcement and strengthening mechanisms.
Abstract: Although carbon materials, particularly graphene and carbon nanotubes, are widely used to reinforce metal matrix composites, understanding the fabrication process and connection between morphology and mechanical properties is still not understood well. This review discusses the relevant literature concerning the simulation of graphene/metal composites and their mechanical properties. This review demonstrates the promising role of simulation of composite fabrication and their properties. Further, results from the revised studies suggest that morphology and fabrication techniques play the most crucial roles in property improvements. The presented results can open up the way for developing new nanocomposites based on the combination of metal and graphene components. It is shown that computer simulation is a possible and practical way to understand the effect of the morphology of graphene reinforcement and strengthening mechanisms.
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