International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 13 Issue: 01 | Jan 2026
p-ISSN: 2395-0072
www.irjet.net
FABRICATION, MECHANICAL CHARACTERIZATION AND STATISTICAL OPTIMIZATION OF ALUMINIUM 7075 METAL MATRIX COMPOSITE REINFORCED WITH COPPER, SILICON CARBIDE AND FLY ASH Dr K. DHARMAREDDY¹, T. LAKSHMANNA² ¹Professor, Department of Mechanical Engineering, Sri Venkateshwara University College of Engineering, Tirupathi, India ²PG Student, Department of Mechanical Engineering, Sri Venkateshwara University College of Engineering, Tirupathi, India -------------------------------------------------------------------------***------------------------------------------------------------------------
Abstract - Aluminum 7075 alloy is widely applicable to the aerospace, automotive, and structural industries as it has a high ratio, but its wear resistance and hardness on the surface are not sufficient to withstand extreme service conditions. In the current study, a hybrid metal matrix composite through the stir casting method was made using Aluminum 7075 reinforced with Copper (Cu), Silicon Carbide (SiC) and Fly Ash. A Taguchi L9 orthogonal array was used to design three levels of reinforcement so as to make the experiments fewer in number but still statistically reliable. The artificial composites were machined as per the ASTM standards, and the strength and hardness of the composite were evaluated in terms of tensile strength. Signal-to-noise (S/N) ratio analysis and Analysis of Variance (ANOVA) were used to statistically optimize between all of these reinforces to assess their contribution to the mechanical performance. As the experimental findings indicate, the addition of SiC leads to great improvement in hardness and tensile strength owing to the high degree of stiffness and loadbearing capacity, which, on the other hand, Copper strengthens the interfacial bonding and ductility by solid solution strengthening effects. The fly ash also helps improve stiffness and reduce weight; therefore, it makes the composite economical and sustainable to the environment. The optimum composition, which is obtained through Taguchi and ANOVA analysis, has better mechanical performance than the base alloy. The research verifies that stir casting is a convenient and economical process in the manufacturing of high-performance Aluminum 7075 hybrid composites that are applicable in high engineering purposes. Keywords: Hybrid metal matrix composite, Silicon carbide, fly ash, Stir casting, Aluminum 7075, Taguchi method, ANOVA.
Introduction The aluminum alloys are important in present-day engineered applications because they are low-density, have high specific strength, possess good corrosion resistance, and are well machinable [1]. Aluminum 7075, among them, is one of the strongest heat-treatable aluminum alloys and has found wide application in aerospace structures, automotive parts and defense applications where the ratio of strength to weight is the most vital [2]. Even though Aluminum 7075 has superior strength and fatigue resistance, Aluminum 7075 has limited wear resistance and average hardness on the surface, limiting its use in components that require high friction and abrasive conditions [3]. Over the recent years, metal matrix composites (MMCs) have been receiving considerable attention due to the fact that they possess better mechanical and tribological characteristics than monolithic alloys [4]. The effectiveness of load transfer and suppression of plastic deformation has been known to help harden, stiffen and increase the wear resistance of aluminum matrices by incorporating hard ceramic reinforcements like Silicon Carbide (SiC) into them [5]. The added content of ceramic particles may, however, render it brittle and ductile in nature. To address this drawback, hybrid metal matrix composite, i.e., mixtures of metallic and ceramic reinforcements have also been suggested to provide a balanced strength, hardness and toughness [6]. Copper finds extensive application as a strengthening agent or an alloying element in aluminum alloys due to its ability to enhance strength by solid solution strengthening as well as precipitation strengthening mechanisms [7]. Recently, fly ash, a by-product of thermal power plants, because of its industrial waste, has also received attention as a low-cost and lightweight reinforcing material and has been shown to contribute to the stiffness increment and environmental friendliness [8]. Adding Copper, SiC and Fly Ash into Aluminum 7075 simultaneously is hence likely to make it a costeffective hybrid composite with higher mechanical performance.
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