ULTRASONIC ASSISTED CASTING OF ALUMINIUM ALLOY MATRIX COMPOSITES

Abstract

Engineering sectors demand materials which can offer such properties which are difficult to obtain through conventional alias. Aluminium metal matrix composites (AMMCs) are the most potential material to fulfil such demands of various engineering sector. ANIMCs have advantages over the conventional alloys. AMMCs can be made by difThrent processing techniques such as powder metallurgy and liquid metallurgy but liquid metallurgy processing techniques have an edge because fabrication is easy. Other processing techniques are also efficient as far as properties are concerned but liquid metallurgy technique is it cost effective for large size components. Factors that govern the selection of material and fabrication process are, ease of fabrication, size and shape of the component. cost, distribution and wettability between reinforced phase and matrix alloy. • A few components that are made tip of AIv1MCs are tennis racket, transfer bench. swash plate toot rest, automobile componenis like casings, head light combos, brake drum, mining equipments, and structural applications components. AMMCs replace either Al-alloy products or east iron products because it reduces weight provide strength, energy efficiency and stiffness. The aerospace industries, automobile and railway sectors are prime sectors fOr AMMCs. Over it half century ultrasonic processing of materials has been employed. It is environmentally favourable, cost effective, and can be combined with other processing technologies, it effectively disperses the particles in molten alloy. Due to ultrasonic processing. agglomeration of particles cannot takes place and it is capable to break big as well as small clusters of particles. in this study we have investigated the effect of ultrasonic stirring in aluminium matrix composite (e\359 + 20 vol % SiC ) willi the reinforcement of I mole % of carbon black. Melting experiments were performed by employing four different conditions. These were - carbon black inoculation along with mechanical stirring, carbon black inoculation along with ultrasonic stining, ultrasonic stirring but no carbon black inoculation and eonro1 specimen (unprocessed). I lardness comparisons between the samples casted at different condition were made. Sample which was ultrasonically treated and carbon inoculated had higher hardness than an unprocessed sample and the samples which was either ultrasonically treated or carbon inoculated. .Mierosrtiettire study revealed that a sample which was ultrasonically treated had tine and globular structure and more uniform distribution of SIC particles than the other IV samples. Porosity was observed with those samples which were not ultrasonically ireated. Al4SiC4 particles were observed but A14C3 particles weren't observed by XRD analysis and EDAX analysis. The 0.2 % proof stress, UTS and elongation of UST and C inoculated Is sample was higher than the unprocessed sample and sample which was C inoculated only. Rejection of carbon was reduced. The thesis includes five chapters in which Chapter 1 gives the brief iniroduction about metal matrix composite (MMCs), aluminium matrix composite (AMMCs), their processing techniques and ultrasonic processing. Chapter 2 gives theoretical background of ultrasonic processing of various composite and work of previous researchers related to this field. Chapter 3 discusses about the experimental methodology used for this dissertation work. Chapter 4 discusses the results which are obtained by conduction different experiments. ChapterS gives the conclusions of the overall work. References are given at the end of the thesis.