Effects of Graphene Nanoplates on the Mechanical Behavior and Strengthening Mechanism of 7075Al Alloy

Leng, Jinfeng; Ren, Binghui; Wang, Ran; Teng, Xinying

doi:10.3390/ma13245808

Cited by 10 publications

(4 citation statements)

References 48 publications

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“…Meanwhile, the microstructure α-Al phase in the thixoformed composite becomes more globular with increasing GNP contents. Furthermore, grain refinement improves the strength and plasticity as the grain size is in microns [ 15 ]. The backscattered electron microscopy images reveal the distribution of eutectic Si (light grey areas indicated with white arrows), α-Al matrix (a dark grey area) and EDS spectrum of the selected area in Figure 6 c,f.…”

Section: Resultsmentioning

confidence: 99%

“…The addition of reinforcement such as silicon carbide (SiC) [ 5 , 6 ], boron carbide (B 4 C) [ 7 ] alumina oxide (Al 2 O 3 ) [ 8 ] are common in AMC while graphene [ 9 , 10 ] and carbon nanotubes (CNTs) [ 11 , 12 , 13 , 14 ] which are made up of carbon-based nanomaterials, have attracted tremendous attention for AMC. Graphene nanoplatelets (GNPs) have become an excellent reinforcement because of their superior mechanical, thermal and electrical properties [ 15 , 16 , 17 ] as compared with CNTs. This material exhibits ultra-high tensile strength up to 130 GPa, an elastic modulus of 1 TPa, a low thermal expansion coefficient and high thermal conductivity [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Behaviour and Morphology of Thixoformed Aluminium Alloy Reinforced by Graphene

et al. 2022

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Thixoforming is a promising method that offers several advantages over both liquid and solid processing. This process utilizes semi-solid behaviour and reduces macrosegregation, porosity and forming forces during the shaping process. Microstructural and mechanical characterization of 0.3, 0.5 and 1.0 wt% graphene nanoplatelet (GNP) reinforced A356 aluminium alloy composite fabricated by thixoforming was investigated. Stir casting was employed to fabricate feedstocks before they were thixoformed at 50% liquid. The microstructure was characterized and evaluated by field emission scanning electron microscopy with an energy dispersive X-ray detector and X-ray diffraction. Mechanical testing, such as microhardness and tensile testing, was also performed to estimate the mechanical properties of the composites. The incorporation of 0.3 wt.% GNPs in Al alloy increased by about 27% in ultimate tensile strength and 29% in hardness. The enhancement in tensile strength is primarily attributed to load transfer strengthening due to the uniform dispersion of these GNPs within the Al matrix, which promotes effective load transfer during tensile deformation, and GNPs’ wrinkled surface structure. Simultaneously, the addition of GNPs enhances the grain refinement effect of the Al alloy matrix, resulting in a grain size strengthening mechanism of the GNPs/Al composites. The results reveal that thixoformed composite microstructure consists of uniformly distributed GNPs, α-Al globules and fine fibrous Si particles. The composites’ grains were refined and equiaxed, and the mechanical properties were improved significantly. This study creates a new method for incorporating GNPs into Al alloy for high-performance composites.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanical Behaviour and Morphology of Thixoformed Aluminium Alloy Reinforced by Graphene

et al. 2022

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“…Two maximum values are observed in the 75/25s and 300/1s samples with an increase in hardness value of~21% compared to the Alp sample and an average contribution to the hardening of~65 VH (see Table 4). Some strength increments for different strengthening mechanisms have been reported, where dislocation contribution to the strengthening was about 25%, and about 60% correspond to the particle dispersion contribution to the strengthening [34]. The addition of reinforcing particles leads to an increase in the number of dislocations, which restricts the free movement of dislocations, increasing the hardness of the compound [35].…”

Section: Strengthening Hardness Contributionsmentioning

confidence: 99%

Effect on Microstructure and Hardness of Reinforcement in Al–Cu with Al4C3 Nanocomposites

Orozco

Beltrán

et al. 2021

Metals

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By superposition, the individual strengthening mechanisms via hardness analyses and the particle dispersion contribution to strengthening were estimated for Al–C and Al–C–Cu composites and pure Al. An evident contribution to hardening due to the density of dislocations was observed for all samples; the presence of relatively high-density values was the result of the difference in the coefficients of thermal expansion (CTE) between the matrix and the reinforced particles when the composites were subjected to the sintering process. However, for the Al–C–Cu composites, the dispersion of the particles had an important effect on the strengthening. For the Al–C–Cu composites, the maximum increase in microhardness was ~210% compared to the pure Al sample processed under the same conditions. The crystallite size and dislocation density contribution to strengthening were calculated using the Langford–Cohen and Taylor equations from the microstructural analysis, respectively. The estimated microhardness values had a good correlation with the experimental. According to the results, the Cu content is responsible for integrating and dispersing the Al4C3 phase. The proposed mathematical equation includes the combined effect of the content of C and Cu (in weight percent). The composites were fabricated following a powder metallurgical route complemented with the mechanical alloying (MA) process. Microstructural analyses were carried out through X-ray analyses coupled with a convolutional multiple whole profile (CMWP) fitting program to determine the crystallite size and dislocation density.

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“…Increment in tensile and hardness was observed up to 0.5wt% of CNTs. While Leng et al [9]fabricated GNPs/Al7075 via stir casting and evaluated graphene's strengthening mechanism. The grain size refinement and dislocation density increase contributes to the GNPs strengthening in AMC composite.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Mechanical Properties and Microstructure of Graphene-Aluminium Alloy Composite Fabricated by Stir Casting Process

Ali,

Omar,

Salleh

et al. 2023

MSF

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Mechanical properties of graphene nanoplatelets (GNPs) reinforced aluminum matrix composite fabricated by the semi-solid stir casting method were investigated. Aluminum alloy A356 is selected based on being widely used in automotive and aircraft industries. Recently, graphene has attracted wide attention from a scientific committee due to its outstanding properties. GNPs are an ideal reinforcement for nanocomposites' productions due to their excellent mechanical properties for strength enhancement. In this study, the effect of different weight fraction of GNPs content (0,0.3,0.5,1.0,and 1.5 wt.%) reinforced with A356 aluminum alloy was analysed. A 45-degree carbide impeller performed the stirring process of 500 rpm for 5 minutes. The samples were then characterised by microscopic examination, Vickers hardness, and tensile test Morphology of the fracture surface of the composite were observed using scanning electron microscopy..The microstructure revealed a homogenous distribution of nanoparticles in the matrix alloy. The composite exhibits improved mechanical properties, maximum tensile strength and hardness of 236MPa and 83 HV are obtained respectively. The composite has shown significant enhancement in the tensile and hardness which is 20% times higher than unreinforced A356 alloy. The hardness increased as the weight fractions of GNP in the A356 matrix has increased. However, when the content of GNPs used above 1.0 wt%, its tensile strength is reduced. Meanwhile, the fracture sample is ductile with a fine dimple structure. These findings may contribute to the process field of semi-solid stir casting, particularly on the GNPs addition to aluminium alloy as their primary material.

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Effects of Graphene Nanoplates on the Mechanical Behavior and Strengthening Mechanism of 7075Al Alloy

Cited by 10 publications

References 48 publications

Mechanical Behaviour and Morphology of Thixoformed Aluminium Alloy Reinforced by Graphene

Mechanical Behaviour and Morphology of Thixoformed Aluminium Alloy Reinforced by Graphene

Effect on Microstructure and Hardness of Reinforcement in Al–Cu with Al4C3 Nanocomposites

Investigation of the Mechanical Properties and Microstructure of Graphene-Aluminium Alloy Composite Fabricated by Stir Casting Process

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