Synthesis and Characterization of Hybrid Metal Matrix Composites (MMCs) Reinforced With Silicon Carbide (SiC) and Aluminium Oxide (Al2O3)
Abstract
This work present Metal matrix composites (MMCs) constitute process which improved properties including high specific strength; specific modulus, damping capacity and good wear resistance compared to unreinforced alloys. When analyses were carried out, two reinforcements namely silicon carbide (SiC) and aluminium oxide (Al2O3) were used for production of hybrid metal matrix composites. The two reinforcements were ball milled in order produce as single entity of these reinforcements. The reinforcement was varied from 0%, 2%, 4%, and 6% to produce hybrid metal matrix composites. All the composites were produced by stir casting. The mechanical properties of the metal matrix composites were investigated. The microstructure and X ray diffraction study was carried out. Similarly, Vickers hardness test, Tensile strength test, Toughness test were also used to investigate the metal matrix composites. After analyses it was found that the Al2O3 and SiC particles were uniformly distributed throughout the metal matrix. The tensile strength and hardness of Al2O3 and SiC reinforcement aluminium composites improved with the increase in volume fraction of nanoparticles and toughness decreases with the increasing volume fraction of reinforcement.
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Introduction
Aluminium & its alloys offer a extensive range of properties that can be engineered accurately to the demands of specific applications, such as in aerospace, advanced nuclear reactors, surface coating and metal/air batteries, through the choice of alloy, temper condition and fabrication process. By utilizing various combinations of its advantageous properties like strength, lightness, corrosion resistance, recyclability and formability, aluminium is being employed in an ever- increasing number of applications. It is good strength to weight ratio, light weight, low density etc, so having such a wide application it attracts more to researchers, and secondly Aluminium shows excellent improvement in its properties on being reinforced with some material. In the given below literature review emphasis is given on the various Aluminium alloys and their work on the different parameters such as mechanical and metallurgical characterization.
Conclusion
The present investigation was aimed to enhance the metallurgical (microstructure), mechanical (hardness, tensile strength and toughness) properties of Al 6101 T6 aluminium base alloy with varying wt.% of SiC and Al2O3 from 0 wt.% to 6 wt.%. Four types of composite materials were produced by Stir Casting process by varying the wt% of SiC and Al2O3 from 0 wt% to 6 wt. % in Al 6101 T6 aluminium base alloy and the following conclusions are made.
The hardness of composite increases with the increasing amount of reinforcement. The addition of 0% to 6% reinforcement resulted in the increase of the hardness by 6.7%, 17.5% and 21.7 respectively in the 2, 4, and 6 wt. % of SiC and Al2O3.
And also it is found that the tensile strength of unreinforced aluminum matrix was lower than that of hybrid composite. Further, addition of SiC and Al2O3 reinforcement 2-6% to aluminium matrix increased the tensile strength by 1% to 11%.
It is found that elongation decreases with increase in particle percentage, which confirms that Silicon Carbide and Aluminium Oxide together increases brittleness.
It was examined that with the addition of SiC and Al2O3 reinforcement up to 4% increases toughness and beyond which toughness decreases. The highest increase in toughness is 114% for 4% reinforcement and the 22% decrease in toughness of sample containing 6% reinforcement can be attributed to lower ductility due to higher density of hard and brittle reinforcing particles and porosity.
The microscopic analysis of these specimens shows that the SiCp and Al2O3p reinforcements are uniformly distributed in the metal matrix. At lower weight % of reinforcement i.e. 2% and 4 % microstructure was more homogeneous than at 6% which was found disorganized due to increased porosity.
Also XRD results confirm the presence of SiC and Al2O3 within the Al matrix of hybrid composite.