Magnesium alloy (AZ91D) composites reinforced with silicon carbide particle with different volume percentage were fabricated by two step stir casting process. The effect of changes in particle size and volume fraction of SiC particles on physical and mechanical properties of composites were evaluated under as cast and heat treated (T6) conditions. The experimental results were compared with the standard theoretical models. The results reveal that the mechanical properties of composites increased with increasing SiC particles and decrease with increasing particle size. Distribution of particles and fractured surface were studied through SEM and the presence of elements is revealed by EDS study.

This paper investigates the mechanical properties and corrosion behavior of Metal Matrix Composites prepared using Al7075 alloy as a matrix, Silicon Carbide and Titanium Carbide as reinforcement particles. Two step stir casting process was used to fabricate the composites by varying volume fractions of Silicon Carbide and Titanium Carbide (0 to 15 vol. %). Microstructural analysis, mechanical and corrosion behavior were used to evaluate the performance of the composites. Uniform distribution of reinforcement particle was observed through optical photomicrographs. Vickers micro hardness tests were performed and the hardness values were increased with an increase in reinforcement from 0 to 15 vol. %. The tensile strength of the 10 vol. % of aluminum hybrid matrix composite was better than that of the base alloy. In 3.5% NaCl solution, it was observed that the 15 vol. % of the aluminum hybrid matrix composite have higher corrosion resistance in comparison the base alloy.

Metal matrix composites are difficult to machine in traditional machining methods. Abrasive water jet machining is a state-of-the art technology which enables machining of practically all engineering materials. This article deals with the investigation on optimization of process parameters of abrasive water jet machining of hybrid aluminium 7075 metal matrix composites with 5%, 10% and 15% of TiC and B 4 C (equal amount of each) reinforcement. The kerf characteristics such as kerf top width, kerf angle and surface roughness were studied against the abrasive water jet machining process parameters, namely, water jet pressure, jet traverse speed and standoff distance. Contribution of these parameters on responses was determined by analysis of variance. Regression models were obtained for kerf characteristics. Contribution of traverse speed was found to be more than other parameters in affecting top kerf width. Water jet pressure influenced more in affecting kerf angle and surface finish. The microstructures of machined surfaces were also analysed by scanning electron microscopy. The scanning electron microscopy investigations exposed the plastic deformation cutting of hybrid 7075 aluminium metal matrix composite. X-ray diffraction analysis results proved the non-entrapment of abrasive particle on the machined surface.

Nowadays, research studies and industrial requirements are directed toward the goals of achieving environmental friendliness, energy savings, and reduced weight. Magnesium and magnesium alloys are well suited for structural and automotive applications owing to their lightweight. However, the reduced hardness and strength of these alloys do pose problems in exploiting their usage. These impediments of lightweight metal matrix can be alleviated by reinforcing hard-phase particles. Different volume percentages of Y2O3 particles (average grain size 5 µm) were added as reinforcements in pure magnesium and magnesium alloy (AZ91D) and the composites were processed through the two-step stir-casting technique. Mechanical and metallurgical characterization studies were carried out on the stir-cast composites under as-cast and heat-treated conditions. Uniform distribution of yttria particles in magnesium and magnesium alloy matrix was observed through scanning electron micrographs. Macro and microhardness tests revealed the increased hardness with the increased amount of yttria reinforcement.

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