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Journal of Manufacturing Science and Engineering-transactions of The Asme, 2008
Magnesium die-cast components are seeing a wider range of application in the automotive industry due to magnesium alloys' excellent castability and low density. With the increased application of magnesium high-pressure diecastings, especially for thin-wall automotive structural components, it is necessary to better understand the relationship between mechanical properties and microstructural features. In the present paper, coupon specimens with a range of characteristic microstructures were tested under tension and 4-point bending loads. The experiments described in this paper correlate the mechanical properties with microstructural and geometric features. These results provide a better understanding of how to predict the mechanical performance of die-cast components.
IJERT-Investigation of Damping Behavior of Aluminum Based Hybrid Nanocomposites
International Journal of Engineering Research and Technology (IJERT), 2014
https://www.ijert.org/investigation-of-damping-behavior-of-aluminum-based-hybrid-nanocomposites https://www.ijert.org/research/investigation-of-damping-behavior-of-aluminum-based-hybrid-nanocomposites-IJERTV3IS090416.pdf In aerospace, automotive and manufacturing industries Aluminum (Al) components have dynamic role. The objective of this paper is to investigate the damping characteristics of Al based hybrid nanocomposites. Commercial purity Aluminum as a matrix, Multi Walled Nano Carbon Tube (MWCNT) and Graphene (GR) as reinforcement with a weight percentage of 0.5%, 1%, 1.5%, 2% have been fabricated by Casting and Powder Metallurgy (P/M) techniques. According to ASTM E756-05 standards damping specimens were prepared and carried free vibration test to investigate damping ratio and natural frequencies of specimens. The results reveals that, Al/MWCNT/GR of 1.5 wt.% having significant improvement in damping ratio and Natural frequency. Beyond increasing weight percentage (1.5 wt. %) of MWCNT and GR deterioration in damping ratio (ζ) and natural frequency (Hz). In this work an attempt has been made to investigate damping characteristics by different fabrication techniques.
Influence of Nanostructuration on the Sound Velocity in Aluminum Al_99.50
IOP Conference Series: Materials Science and Engineering, 2018
The paper proposes is a multidisciplinary study on the influence of nanostructured material obtained by cyclic closed die forging process, in this case the aluminum with a purity of 99.50% (Al_99.50), on the sound velocity. The study of nanomaterials is a branch of material science on the basis of which nanotechnology can be approached. Severe plastic deformation (SPD) is a generic term describing a group of metal and alloy processing techniques involving very high stresses without including significant changes in the overall dimensions of the model or workpiece. The sample is of a regular quadrangular prism shape with the side square of a = 10 mm and the height of h = 16 mm, so with a dimensional factor h / a = 1.6. For each sample, a number of 7 determinations were performed to establish a mean value for the sound velocity. As a result of the microstructure analysis, it is observed that at the deformation cycle 4 the grains have an average size between 250 and 500 nm.
Effects of the morphology and structure on the elastic behavior of (Ti,Si,Al)N nanocomposites
Surface & Coatings Technology, 2003
d bstract (Ti,Si,Al)N nanocomposite coatings with different Ti, Si, Al contents, were deposited onto silicon and polished high-speed steel substrates, by r.f. andyor d.c. reactive magnetron sputtering. The stoichiometry of the films was investigated by electron probe microanalysis and Rutherford backscattering spectrometry (RBS). The density was derived by combination of RBS results and thickness measurements obtained by ball-cratering. For comparison purposes, the evaluation of the Young's modulus was performed by depth-sensing indentation technique and with the laser-acoustic technique based on surface acoustic waves (SAW). Results showed in some cases differences in Young's modulus measured by both techniques. The Young's modulus obtained by SAW correlates with the density values from RBS, however, this behavior is not visible for the results measured with the ultramicroindentation technique. Both techniques indicate a small increase of Young's modulus of (Ti,Al)N by incorporating Si into the matrix. However, this improvement only occurs for small Si content, whereas for high Si content the elastic parameter reduces until almost 300 GPa. The morphology of the coatings was investigated by scanning electron microscopy and correlated with the differences observed by both SAW and indentation techniques.
2016
Transmission electron microscopy (TEM) was used to study the particle size of the nanopowder. The metal matrix composites (MMCs) were manufactured by liquid metallurgy technique using vortex method. Aluminium-6061 (Al-6061) alloy was used as matrix which is reinforced with 2, 4 and 6 weight percentage of α-Al2O3 nanoceramic powder. Scanning electron microscopy (SEM) analysis was used to study the distribution and homogeneity of the α-Al2O3 particles in the Al-6061 matrix. Results show that addition of α-Al2O3 nanoceramic powder as reinforcement has a drastic effect on the mechanical properties like hardness, compression strength and ultimate tensile strength (UTS) of the MMCs when compared with that of Al-6061 matrix. Further, the increased % age of α- Al2O 3 nanoceramic powder contributed in increased hardness, compression strength and ultimate tensile strength the MMCs. In the current article solution combustion synthesis method was used to prepare α-Al2O3 nanoceramics. Powder x-ray diffraction (PXRD) studies were done to study the phase formation and calculate crystallite size of α-Al2O3 nanoceramics. In this study, machinability test was conducted on Al-Nanoclay metal matrix composites using lathe tool dynamometer. Composites were prepared with aluminium as the matrix and nanoclay particles with 2, 4, 6 percentage by weight as reinforcement. The effect of clay particles and machining parameters such as cutting speed, feed rate and depth of cut on tangential force and chip formation was studied. From the results it is observed that the tangential force applied by the tool on MMC, facilitate chip breaking and the generation of chips significantly depends on feed but almost independent of speed. These results reveal the roles of the nanoclay reinforcement particles on the machinability of MMCs and provide a useful guide for a better control of their machining processes.
Advanced Engineering Materials, 2020
A quantitative understanding of the role of ultrasonic treatment process variables on microstructure and mechanical properties is critical for the development of process maps for manufacturing metal matrix composites. This paper presents a novel mathematical framework to delineate the functional correlations between ultrasonication time, grain refinement, and hardening in SiC nanoparticle reinforced Al matrix composites. Ultrasonic treatment generates microbubbles and deagglomerates SiC to increase heterogeneous nucleation sites synergistically. The increase in volumetric nucleation density due to SiC addition exhibits slow exponential kinetics with varying ultrasonication time. An outstanding grain refinement efficiency of 62.8% is achieved upon ultrasonication for 90 s. The contributions to an increase in the hardness due to grain refinement and SiC dispersion are isolated to develop correlations between ultrasonication time and hardening. Hardening increases exponentially with treatment time due to the reduction of interparticle distance from sonication induced SiC dispersion. These fundamental mathematical correlations constitute a significant advancement towards the development of ultrasonic process maps and metal matrix composite manufacturing technology.
Nfluence of Nanostructuration on the Sound Velocity in Aluminum AL_99.50
European Journal of Materials Science and Engineering, 2017
The paper aims to determine the influence of nanostructure on sound velocity, to severe plastic deformation by cold multiaxial forging of aluminum. The deformation process is discontinuous and comprises deformation processes defining a severe plastic deformation cycle. Thus, a number of 7 determinations were performed for each sample, corresponding to the first 12 cycles of severe plastic deformation. As a result of the analysis of the results, it can be deduced that the area of passages 3, 4 and 5 represents, in fact, precisely the transition zone between micrometric granulation and mesoscopic (ultrafine) granulation, which is only
Applied Physics Letters, 2008
We determined the isotropic indentation modulus of precipitates in cubic materials by using the indentation modulus of the matrix as a reference. This eliminates major practical difficulty of repeatedly switching between a sample and a reference for measurement of indentation modulus using atomic force acoustic microscopy. The methodology has been demonstrated for mapping the elastic stiffness of ϳ500 nm sized M 23 C 6 precipitates in alloy 625 and ferritic steel with a spatial resolution of ϳ50 nm.
On the Elastic Field of Al/SiC Nanocomposite
2017
This study aims to analyze the linear elastic behavior of an aluminum matrix nanocomposite reinforced with SiC nanoparticles. Once, a representative volume element was considered for the nanocomposite with a cuboidal inclusion. The elastic moduli of the matrix and the inclusion were the same, but it contained eigenstrain. The stress and the strain fields were obtained for the inclusion and the aluminum by Galerkin vector method. The stress and the strain fields in the inclusion problem were in a good agreement with the results in the literature. A similar representative volume element was considered for the nanocomposite with a cuboidal inhomogeneity. The elastic moduli of the matrix and the inhomogeneity were different, but it did not have any eigenstrain. For the calculation of the Eshelby tensor and the elastic fields for the inhomogeneity problem, the equivalent inclusion method (EIM) was applied. In the EIM, the uniform and equivalent eigenstrain were considered. The stress and the strain fields within the inhomogeneity and the matrix were obtained. Results showed that the stress and the strain in the cuboidal inclusion were less than the cuboidal inhomogeneity due to the difference between the matrix and the reinforcement materials.
Journal of Manufacturing Processes, 2016
Metal matrix nanocomposites (MMNCs) can offer significant improvement of properties such as higher specific strength, specific modulus, controlled thermal expansion and higher corrosion resistance, compared to the base metallic materials. However, agglomeration or clustering of nanomaterials makes it very difficult to disperse them in the metal matrix. Non-linear effects of ultrasonic processing, such as acoustic cavitation and acoustic streaming, help in the dispersion and distribution of the nanomaterials. Non-linearity of the ultrasonic processing makes it very hard to measure or characterize the process experimentally. There is very limited knowledge about the interactions between the geometrical parameters of the ultrasonic processing and the extent of cavitation achieved. Numerical modeling offers powerful tools to overcome the experimental difficulties involved. In this study, a non-linear numerical model was developed to resolve the acoustic pressure field, and the cavitation zone size was quantified from the numerical modeling results. The model was then used to study the effect of geometry on the cavitation zone size. Analysis of variance (ANOVA) was used to identify the significant parameters. A parametric analysis involving these parameters was subsequently performed. A configuration of geometrical parameters offering the highest cavitation zone size was determined. It was found out that a probe immersion depth of 25.4 mm produced a maximum cavitation zone in the ultrasonic processing cell with a diameter of 35.9 mm for processing 57 ml of molten Al alloy. An experimental validation has been accomplished by ultrasonically processing an aluminum alloy with carbon nanofibers and silicon carbide microparticles. With selected parameters the area of micro pores in the MMNC was significantly decreased by 50% and a deviation of the hardness was also decreased by 46% due to further dispersion and distribution of the carbon nanofibers.