Preparation of aluminium 6063-graphite surface composites by an electrical resistance heat assisted pressing technique

Joseph

Journal of Composite Materials

et al. 2018

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Influence of particle size and shape of carbonaceous materials on the surface mechanical properties of Aluminium-1100 substrates is evaluated. The aluminium surface is impregnated with multiwalled carbon nanotubes (one dimensional), Graphene nanoplatelets (two dimensional) and graphite flakes (three dimensional) of various sizes. An electrical resistance heat assisted pressing technique was used for localised melting of the aluminium substrate followed by the mechanical impregnation of the carbonaceous materials. Surface mechanical properties of the so obtained surface composites were evaluated by microhardness and nanoindentation studies. A general observation is that the indentation hardness and Young’s modulus increase as the shape changes from three dimensional to one dimensional and also with the reduction in particle size. The maximum surface hardness achieved for each of these particles and the processing conditions at which the best properties are attained give insights into the prevailing hardening mechanisms. Raman spectroscopic analysis, which shows a variable shift and change in intensity ratios of the corresponding G, D and 2D bands, corroborates the experimental observations.

Section: Methodsmentioning

confidence: 99%

Particle size and shape effects on the surface mechanical properties of aluminium coated with carbonaceous materials

Joseph

Journal of Composite Materials

et al. 2018

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“…The Raman peak at 2700 cm −1 corresponds to the two-phonon scattering mode and is known as a 2D band. The 2D band signifies the degree of graphitization present in the structure [37,38].…”

Section: Raman Spectroscopymentioning

confidence: 99%

Study of Nano-Mechanical, Electrochemical and Raman Spectroscopic Behavior of Al6061-SiC-Graphite Hybrid Surface Composite Fabricated through Friction Stir Processing

et al. 2018

J. Compos. Sci.

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Aluminium-based hybrid metal grid composites (MMC) are extensively utilized in automobile applications (engine cylinders, pistons, etc.) as they exhibit a fantastic blend of properties. Here, a detailed study of nano-mechanical, electrochemical and Raman spectroscopic behavior of friction stir processed Al6061-SiC-graphite hybrid surface composite is presented. The effect of various tool rotational speeds was evaluated along with the monitoring of variation in axial force. Microstructural changes with various tool rotational speeds are studied by using a scanning electron microscope. Raman spectroscopy and X-Ray diffraction studies are used for the spectroscopic characterization of the fabricated hybrid and mono surface composites. Residual stresses and various crystal structure disorders of reinforcement result in the significant change in intensity and a considerable shift in Raman peak positions. The nano-mechanical behavior of the fabricated composite with various reinforcements and tool rotational speeds are analyzed by using nano-indentation. The nano-mechanical behavior of hybrid composite fabricated with an optimum set of processing parameters is superior to mono composites fabricated with the same processing parameters. Also, the electrochemical behavior of the fabricated composites is studied by linear potentiodynamic polarization test. The Al6061-SiC-graphite hybrid surface composite reveals excellent nano-mechanical and electrochemical behavior when fabricated with an optimum set of processing parameters. The tool rotational speed has a pronounced effect on the dispersion of agglomerates and grain refinement of the matrix material. The processing parameters extensively affect the Raman spectroscopic behavior of the hybrid composite. The hybrid surface composite shows better corrosion resistance than the mono composites when fabricated with an optimum set of processing parameters. Reduced intergranular as well as interfacial corrosion pits in hybrid composites increased its resistance to corrosion.

“…The shearing up of graphite into FLG is confirmed by Raman spectroscopy as shown in figure 4b. The high-intensity D band in the Algraphite composite corresponds to the defects in exfoliated graphene layers [21,22]. The intensity ratio I D /I G is increased from 0.15 in the as-received graphite to 0.74 in the composite.…”

Section: Methodsmentioning

confidence: 96%

Effect of exfoliated few-layered graphene on corrosion and mechanical behaviour of the graphitized Al–SiC surface composite fabricated by FSP

et al. 2019

Bull Mater Sci

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The influence of friction stir processing parameters and the subsequent evolution of microstructures and corrosion behaviour of Al-SiC surface composites fabricated in the presence of graphitic flakes are presented in this paper. The circumferential shear stress exerted by the rotating tool exfoliates the graphite flakes into few-layered graphene during processing. These graphene flakes preferentially occupy both the grain boundaries and the SiC-Al interface during recrystallization. The potentiodynamic polarization test, in 3.5 wt% sodium chloride (NaCl) solution, is conducted for samples processed at various tool rotational speeds and it is found that the presence of this thin graphitic layer at these locations reduces the intergranular and interfacial corrosion to a great extent. The tool rotational speed has a significant influence on processing, and samples fabricated at an optimum tool rotational speed of 2200 rpm shows better corrosion resistance and mechanical properties as compared to that at lower and higher speeds. Raman spectroscopic analysis, X-ray diffraction studies and microhardness tests corroborate the experimental results and the proposed mechanisms.