Studies on Structural and Mechanical Properties of Carbon Nanotube Dispersed Tungsten Carbide Cobalt Nano Micro Composites

Abstract

The present thesis describes the preparation of the WC-Co nano/micro composite, wherein VC is varied from 0, 2.5, 5, 7.5 and 10 wt.% in a systematic way. The optimized WC-Co-VC nano/micro composites have been selected to study the effects of CNTs on various properties. These samples are characterized by various techniques. The results obtained from various techniques are correlated and supported by the existing and available literature. The results and observations are correlated in terms of different crystalline phases formations, their volume factions, density and microstructural changes with addition of CNT and VC in base composition i.e. WC-Co. These microstructural changes are correlated with the mechanical like hardness, fracture toughness and wear properties. The thesis is divided into five chapters with a list of cited references at the end of thesis. WC-Co nanocomposites, process, properties and their applications are discussed in chapter 1. Alternate materials, which are being used now for some special purpose such as machining, are also discussed. Brief account about all advanced ceramics bear high initial cost apart from limitation of their usage only in specialized machining are also given. Advanced ceramic materials have few advantages over the conventional carbides, still the usage of WC as cutting tool and die materials is the highest among all the materials. Easy manufacturing, relatively lower cost and good reliability are among various factors, which favor the need of development in conventional carbides. The chapter ends with the basic structure, physical, mechanical, thermal and wear properties of WC-Co composites along with properties of its individual constituents. Reviews of the literature related to the various aspects of sintering WC-Co composites containing variable quantities of different grain growth inhibitor are summarized in second chapter. Various conventional and non-conventional methods of sintering WC composites by different researchers is correlated in terms of processing