Influence of Fine Al2O3 and Aluminium Nano-Particles on the 6061 Aluminium Alloy near the Grain Boundary of the Semi-Solid Cast Microstructure
23 Jun 2019-Transactions of The Indian Ceramic Society (Taylor & Francis)-Vol. 78, Iss: 2, pp 94-100
TL;DR: Dual mixed slurry for AA6061/Al2O3-Al powder was formed under argon gas protection and used to fabricate composite due to the effect of free vortex flow in semi-solid stage as discussed by the authors.
Abstract: Dual mixed slurry for AA6061/Al2O3-Al powder was formed under argon gas protection and used to fabricate composite due to the effect of free vortex flow in semi-solid stage. Initially, Al2O3 reinfo...
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TL;DR: In this article, the nano-Ni-Al2O3/A356 nanocomposites were prepared with nickel-plating, stir casting, and equal channel angle semi-solid extrusion (ECASE).
Abstract: The nano-Ni-Al2O3/A356 nanocomposites prepared with nickel-plating, stir casting, and equal channel angle semi-solid extrusion (ECASE). The microstructure, tensile property, and fracture morphology of the fabricated nanocomposites have been investigated. The microstructure observation showed the nickel-plating could stimulate nucleation and break nanoparticle aggregation, resulting the matrix grains in a smaller size (63 μm) and the nanoparticles more uniform located on the grain boundary. The ECASE could further refine the grains size (23 μm) and improve the nanoparticle dispersion. Although 5 passes refine the grains to 16 μm, it would cause the particles to re-agglomerate, due to the nanoparticles exist in the semi-solid liquid phase for a long time. The fabricated nanocomposites exhibited an enhancement in both strength and ductility, about 1.2–2.5 times higher than those of the corresponding aluminum matrix composites. Due to the Orowan strengthening and fine grain strengthening, i.e., increased the number of grain boundaries and improved the resistance of particles to cooperative grain deformation. Meanwhile, the ECASE eliminated the intergranular defects and improved the grain boundary bonding. The enhanced mechanical properties of the nanocomposites were attributed to the grain boundary control increased by the nickel-plating and ECASE. The grain boundary control, such as increasing the grain boundary number, improving the particle-matrix adhesion and particle dispersion, can be applied to the development of high mechanical properties aluminum matrix composites.
7 citations
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TL;DR: In this article, the effect of reinforcement incorporation has been investigated according to Reinforcement Incorporation Factor (RIF), Microstructure, Density and Micro-indentation hardness measurement.
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TL;DR: In this article, a semi-solid casting method is used to reduce the cavity formation during the solidification in the conventional casting process, which affects the cast properties and microstructure.
Abstract: Cavity formation during the solidification in the conventional casting process affects the cast properties and microstructure. This is generally reduced with help of semi-solid casting and several ...
3 citations
TL;DR: In this article, powder metallurgy route was employed to synthesize SiO2 (5, 10 and 15 vol%) coated aluminium borate whisker (ABOw) reinforced aluminium composites.
Abstract: In this investigation, powder metallurgy route was employed to synthesize SiO2 (5, 10 and 15 vol%) coated aluminium borate whisker (ABOw) reinforced aluminium composites. Commercial pure aluminium ...
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10 Mar 2014
TL;DR: In this paper, the most important manufacturing techniques used for the synthesis of bulk metal matrix nanocomposites are reviewed and the strengthening mechanisms responsible for the improvement of mechanical properties of nano-reinforced metal matrix composites have been reviewed.
Abstract: Metal matrix composites reinforced by nano-particles are very promising materials, suitable for a large number of applications. These composites consist of a metal matrix filled with nano-particles featuring physical and mechanical properties very different from those of the matrix. The nano-particles can improve the base material in terms of wear resistance, damping properties and mechanical strength. Different kinds of metals, predominantly Al, Mg and Cu, have been employed for the production of composites reinforced by nano-ceramic particles such as carbides, nitrides, oxides as well as carbon nanotubes. The main issue of concern for the synthesis of these materials consists in the low wettability of the reinforcement phase by the molten metal, which does not allow the synthesis by conventional casting methods. Several alternative routes have been presented in literature for the production of nano-composites. This work is aimed at reviewing the most important manufacturing techniques used for the synthesis of bulk metal matrix nanocomposites. Moreover, the strengthening mechanisms responsible for the improvement of mechanical properties of nano-reinforced metal matrix composites have been reviewed and the main potential applications of this new class of materials are envisaged.
740 citations
TL;DR: The hardness and tensile properties of aluminum matrix composites reinforced with nanometric Al2O3 particulate have been found to increase with the volume fraction of the reinforcement.
460 citations
15 Nov 2011-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a three-step mixing method was used to improve the wettability and distribution of reinforcement particles within the matrix, which included heat treatment of micro and nano Al2O3 particles, injection of heat-treated particles, and stirring the melt at different speeds.
Abstract: Aluminum matrix composites (AMCs) reinforced with micro and nano-sized Al2O3 particles are widely used for high performance applications such as automotive, military, aerospace and electricity industries because of their improved physical and mechanical properties. In this study, in order to improve the wettability and distribution of reinforcement particles within the matrix, a novel three step mixing method was used. The process included heat treatment of micro and nano Al2O3 particles, injection of heat-treated particles within the molten A356 aluminum alloy by inert argon gas and stirring the melt at different speeds. The influence of various processing parameters such as heat treatment of particles, injection process, stirring speed, reinforcement particle size and weight percentage of reinforcement particles on the microstructure and mechanical properties of composites was investigated. The matrix grain size, morphology and distribution of Al2O3 nanoparticles were recognized by scanning electron microscopy (SEM), optical microscope (OM) equipped with image analyzer, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Also, the hardness and compression strength of samples was investigated. The results showed the poor incorporation of nano particles in the aluminum melt prepared by the common condition. However, the use of heat-treated particles, injection of particles and the stirring system improved the wettability and distribution of the nano particles within the aluminum melt. In addition, it was revealed that the amount of hardness, compressive strength and porosity increased as weight percentage of nano Al2O3 particles increased.
404 citations
TL;DR: In this paper, the authors show that dislocation density increases with an increase in the volume fraction of SiC and decreases with the increase in particle size of the SiC, and that the subgrain size decreases with volume fraction and increases with particle size.
Abstract: The addition of discontinuous silicon carbide (SiC) to aluminum (Al) alloys can result in a five-fold increase in the yield stress. The magnitude of the increase is obviously a function of the volume fraction and the particle size of the SiC. Previously, it was proposed that the strength increase due to SiC addition to Al alloys was the result of change in the matrix strength, i.e. an increase in dislocation density and a reduction of subgrain size. The data obtained from a series of experiments indicate that dislocation density increases with an increase in volume fraction of SiC and decreases with an increase in particle size. The subgrain size decreases as the volume fraction increases and increases as the particle size increases. There is a good correlation between the microstructural changes in the matrix and the changes in the yield stress of the composites.
360 citations
TL;DR: In this paper, the authors investigated the tensile performance and fracture behavior of aluminum matrix composites reinforced with TiB2 nano and microparticles, and found that the porosity of the composites increased with increasing volume fraction and decreasing particle size.
317 citations