Investigation of Mechanical and Tribological Properties of LM6-Fly Ash Metal Matrix Composite

Introduction

The auto industry is constantly revolutionizing fuel efficiency by restricting the weight of the vehicle without sacrificing its appearance, which leads to the use of materials with lightweight (Kulekci, 2008). Because of its easy accessibility, simple machinability, high stiffness and strength to weight ratio, simple casting process, sturdiness, flexibility and pliability, aluminum, one of the lightest fundamental materials, is widely used (Chawla et.al. 2004). Accordingly, aluminum and aluminum amalgams are step by step replacing ferrous parts, such as alternator covers, water siphons in cars, intake pipe, extra segments in low-load areas, oil compartment, valve covers etc. (Macke et. al. 2012). Accordingly, an approach has been made in this current study to fabricate and analyze Al-based composites. Further, Aluminum based Metal Matrix composites (MMC) have obtained enhanced attention in recent times as designing materials because of its improved high strength, hardness and resistance to wear over traditional Al alloys (Shanmughasundaram et.al. 2011). Metal matrix composites provide an opportunity for the automotive industry to reduce vehicle weight and improve execution (Macke et. al. 2012) (Chawla et.al. 2004). Aluminum is used in automobiles because of its appealing features (Suresh et. al. 2010), (Sulaiman et. al. 2008). Umesh et. al. (2016) investigated with LM6 grade of aluminum alloy as base lattice with silicon content at high amount and reported superior wear resistant and thermal properties. The reinforcement added to the aluminum composites are of two sorts. Manufactured ceramic support i.e Al₂O₃, TiC, SiC, SiO₂, B₄C, BN, MgO, ZrB₂, TiB₂ and so forth are costly and restricted accessibility and non-earthenware reinforcement i.e rock dust, fly ash particle, red mud, agro scatters and so on (Fatile et. al. 2014) (Loh et. al. 2013). The Manufacturing cost of aluminum alloy supported with ceramic support is very high. Because of significant expense of ceramic reinforcement analysts are zeroing in on substitute inexpensive reinforcements. Fly debris is such particulate found as industry squander at thermal power plants because of consuming of coal. Fly ash improves mechanical properties like damping, hardness and so forth of MMCs as support since it contains enormous rate per unit volume (Rajan et. al. 2007). Fly ash has a number of features that make it an excellent support, including high electrical resistance, low thermal conductivity, low density and the fact that it is a low-cost waste material. Among different dispersoids utilized, Fly ash is likely the most cost-effective and low-density support available in large quantities as a strong waste product of coal combustion in nuclear power plants. Precipitator and cenosphere are the two types of fly ash particles. Precipitator fly ash is made up of strong circular particles of fly debris, while cenosphere fly ash is made up of empty cylindrical particles of fly ash with a density less than 1.0 g/cm³. As a result, it is envisaged that the consolidation of fly ash particles in aluminum alloy will advance the exploitation of this minimal cost waste result while also having the ability to save energy escalated aluminum, lessening the expense of aluminum products (Rohatgi. 1994) (Rajan et. al. 2001) (Rohatgi et. al. 1997). The fly ash contains the main synthetic constituents like Al₂O₃, SiO₂, Fe₂O₃ and CaO. It comprises quartz, magnetite, hematite, mullite, spinel, alumina and ferrite. The inclusion of fly ash particles in the Al matrix improves wear resistance, damping characteristics, hardness, stiffness and density (Keshavaram et. al. 1984) ( Rohatgi et. al. 1998). Al alloy with particulates like SiC (Balasivanandha prabu et. al. 2008), Al₂O₃ (Muthusamy, 2012), B₄C (Rama Rao et. al. 2012), Si₃N₄ (Ramesh et. al. 2010), TiC (Senthilkumar et. al. 2011) reported improved outcomes under various factors and fabrication route. Precipitator fly ash is used as particles for reinforcement in AMMC in this study. The present study aims to combine Aluminum alloy – fly ash composites (2, 4, 6% fly ash by weight) with the stir casting process, with the goal of describing better mechanical properties in terms of tensile strength, density and hardness. Powder metallurgy (Rahimian et. al 2009), stir casting (Soundararajan et. al 2018), squeeze casting (Soundararajan et. al. 2015), mechanical alloying (Srinivasrao et. al. 2009), compo casting (Selvam et. al. 2013), and spray deposition (Srivastava et. al. 2005) are a portion of the exemplary strategies that have been utilized to make AMCs with different kinds of fortifications. The AMCs' characteristics are also influenced by the processing procedure. Fly ash, a filler material and support in metal matrix composites (MMCs) has been the subject of recent research. Simply adopting a basic fabrication procedure, a large volume of metal matrix composite can be created with less expensive reinforcement, lowering the composites cost (Madhu Kumar Y C et al, 2012). Of all the accessible methods of fabrication, stir casting or liquid metallurgy is the most efficient course for the assembling of metal grid composite (Surappa, 1997). Anilkumar et al. (2011) tested Al6061 with fly ash that had been stir cast. They inferred that the rigidity and hardness expanded with an expansion in the weight level of fly ash. Anyway there is decline in the elasticity of MMC with fly ash by 15%, due to the poor wettability of the reinforcement with the matrix. Researchers additionally found that the wear rate diminished with the rise in size of fly ash particles. Arun L.R. et al. (2013) uncovered that a rigidity has furthermore improved by 23.26% over base metal with the extension in fly ash weight rate. Sandeep kumar Ravesh et al. (2012) examined impact of SiC and fly ash on aluminum. It shows up in this examination as tensile Strength and hardness increment with expansion in weight level of SiC. The best consequence of elasticity has been obtained at 10% weight level of SiC and 5% of Fly Ash. Shanmughasundaram et.al (2011) uncovered that the fly ash particles essentially improve the compressive strength and elasticity of Al alloy. Anyway the two properties of the composites start to drop when the fly ash content expanded from 20% to 25 wt%. Researcher likewise uncovered that the diminishing propensity in wear rate of the Al-fly ash composites was seen when the sliding rate increases. Vivekanathan et.al (2011) revealed that the impact of expanded support on the wear conduct of the MMCs is to build the wear resistance and diminish the coefficient of friction. The MMCs showed better wear resistance because of its prevalent load bearing limit. It is also revealed that increment in hardness and UTS has taken place due to dispersion strengthening with particle reinforcement. Dr.Selvi.S et.al (2013) researched the mechanical properties of Al-MMCs and contemplated that the hardness and wear obstruction of the Al-MMC composites increases as the fly ash content rises. The goal of this study is to do further research on size (150–175 μm) of fly ash, which is mostly ignored in most research studies yet plays a critical role in improving MMC performance.