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About this book

This book focuses on surface engineering of a wide range of modern materials such as smart alloys, light metals, polymers, and composites etc. for their improved manufacturability. It discusses the effect of surface engineering processes namely friction stir processing, forming, spark erosion, welding, laser heating, and coating etc. on various properties of modern materials. The book aims to facilitate researchers and engineers for manufacturing modern materials for numerous commercial, precision and scientific applications.

Table of Contents

Frontmatter

Friction Stir Processing: An Emerging Surface Engineering Technique

Abstract
Surface modification technologies impart improved surface properties without affecting the bulk properties of the material. The properties could be mechanical, electrical or thermal properties. Until recent past, thermal spray techniques, namely, plasma spraying, high-velocity oxy-fuel coatings and many others widely used for these applications. Friction stir processing (FSP) is a relatively newer technique that uses friction (between two surfaces) as a heat source to form a surface composite on the base alloy. This solid-state process not only refines the given structure but also disperses the reinforcements well within matrix alloy to enhance the surface properties. FSP was earlier employed to low melting point alloys such as aluminum and magnesium-base alloys, but now, with the recent development in tool geometry and tool materials, it can even be effectively used for high melting point alloys like steel and titanium-based alloys. Several process parameters seem to affect temperature and dispersion of reinforcements at the surface. They include rotational speed and traverse speed of the tool, number of passes, cooling medium and the tool geometry. Among these, rotation speed and traversing speed of tool seem to greatly affect the temperature distribution in the plasticized zone formed at the surface. This temperature, in turn, affects the grain refinement and dispersion of reinforcement particles. The present chapter summarizes the effect of these parameters. This chapter also reviews the latest developments in the tool material and its design. Further, their role in augmenting the base alloy properties is also discussed. High hardness, high fracture toughness, chemical inertness and high-temperature strength are few desirable properties of a tool to be used for FSP. In the end, the applicability of FSP as a surface modification technique has been assessed.
Padmakumar A. Bajakke, Sudhakar C. Jambagi, Vinayak R. Malik, Anand S. Deshpande

Development and Surface Engineering of TiNi Shape Memory Alloy

Abstract
Shape memory alloys are currently replacing many conventional materials due to their various useful properties. Besides shape recovery above austenitic temperature and pseudo-elasticity, high strength and good corrosion properties are one of the many mentionable properties of these alloys. Due to their intriguing properties, aerospace, biomedical and automotive industries are leading the research frontier for these smart materials. This chapter presents the results of an experimental investigation conducted on development of Ti rich shape memory alloy by arc melting and hot rolling, and its surface study when machined by wire-EDM. The developed and machined specimens of TiNi alloys were also tested. Tensile study of the specimens showed that material rigidity has decreased due to intensive rolling process. Scan electron microscopic analysis of the fractured surface confirmed that the mode of failure of the rolled specimen was ductile in nature. Characteristic properties like necking, dimple formation, cracks which are related to ductile failure of metallic materials are clearly visible in the SEM micrographs. Micro hardness test revealed that micro hardness of the rolled specimens are much higher than as cast TiNi alloy and less along the edge of the fracture surface compared to bulk rolled material.
Hargovind Soni, S. Narendranath, P. M. Mashninini, Abhinaba Roy, T. Sebin Binoy, K. Jyothi, J. Rojina, Abhilash Krishnan

Wear of Rubbers and Its Control in Conveyer Belt System

Abstract
Rubbers are polymer materials characterized by the ability of reversible deformation under influence of external deformation forces, described as a material with elastic properties. Rubbers include natural rubber, naturally occurring substance and synthetic rubber, artificially derived from petrochemical product. Products made from rubber have flexible and stable 3-dimensional chemical structure and the ability to stretch repeatedly of about twice the original length and return to original length. These materials are enormously used in conveyer belt system. Today, rubber materials are altered with approximately 60% synthetic polymers to achieve desired properties of final product. This chapter investigates the wear of different types of rubbers against ceramic liners which is the most realistic case in mining industries, where conveyor belts are used for ore transportation pulleys in conveyer belt system are coated with sacrificial liners of ceramics and rubbers to prolong the life of the conveyor system. However, such pulley liners are exposed to wear and even chemical reactions particularly in mining industries that are involved in transporting ores. The investigation will provide information on surface in terms of wear mechanism of rubber against ceramics, wear rate and appearance of wear surfaces.
Dilip Thapa Masrangi, Hadinata Salim, F. Hakami, A. Pramanik, A. K. Basak

Surface Characteristics When Solid State Welding of Aluminium Alloys to Magnesium Alloys

Abstract
In the past two decades, there has been an ever-increasing demand for solid-state welding of dissimilar materials. This type of solid-state welding technique is gaining prominence in various disciplines but more importantly in naval, marine, aerospace and military applications. Most of the leading car manufactures today are exploring the possibilities of joining magnesium with aluminium, via solid-state welding process. In the present scenario these techniques are applicable for automotive applications like transmission cases and oil pans. In this work, the different types of solid-state welding techniques that were used for joining of aluminium alloys with magnesium alloys are reviewed from different perceptions. One of the important issues that is faced during joining of these dissimilar materials, is the formation of intermetallic compounds (IMCs) at the welded interface. The work also highlights the influence of various process parameters, structural morphology, intermetallic compound formation and variations in mechanical properties. Some of the important Solid-state welding processes that are elucidated here includes: friction welding, friction stir welding, friction stir spot welding, diffusion welding and third body welding. The above said techniques are carefully analysed for the formation of a satisfactory and quality sound aluminium-magnesium joints. In the overview, it can be summarized that friction-based joining processes have great potential to obtain sound Al–Mg joints. The amount of frictional heat generated at the surface of the contact helps to decide the type and volume fraction of IMCs that are subsequently affecting the mechanical properties of the joints. The joint properties can be enhanced by optimizing the process parameters.
P. Shenbaga Velu, N. J. Vignesh, N. Rajesh Jesudoss Hynes

Analytical Modelling for Laser Heating for Materials Processing and Surface Engineering

Abstract
Light amplification by stimulated emission of radiation (laser) is an organized monochromatic electromagnetic radiation beam which can proliferate linearly with negligible disparity and the source of energy is found in broad spectrum of wavelength. Laser has been witnessed as ample applications in thermal processing right from material processing to thermal therapy for cancer treatment. The laser processing of materials can be classified as: laser assisted machining, forming, joining and surface engineering. The emitted energy source from laser can be spotlighted into a small spot and it caters a large amount of intense energy which is quintessential for penetration in materials for surface treatment. In this book chapter, exact analytical solution of three-dimensional dual-phase-lag heat conduction model has been developed under the influence of non-Gaussian time and space dependent laser heat source. The corresponding mathematical solution is obtained with implementation of ‘Finite integral transform’ and ‘Duhamel’s theorem’. The consequence of lagging behaviour on laser heating has been studied. The laser heating process variables such as laser exposure, power density have been investigated with temperature variation. The development of surface thermal contours defines the heat flow in the substrate domain. The accuracy of present mathematical modelling has been justified based on the physical phenomena observed under laser heating.
Jaideep Dutta, Balaram Kundu, Hargovind Soni, Peter Madindwa Mashinini

Surface Roughness and Morphology Studies on Machining Hybrid Composite Material Using Abrasive Water Jet Cutting Process

Abstract
The accelerated demands of engineered products with superior properties have inspired researchers to investigate the substitutes of the manmade fibre-based composites and explore the utilization of natural fibre based polymer matrix composites (PMC). Although manmade fibres have many benefits, but their decreasing usage in decade has been due to high primary cost, non-bio degradability, non-renewability, high energy ingestion in engineering process and unfavourable eco-friendly effects. Bio fibres still compensate for their deprived compatibility with the matrix, naturally high moisture absorption rate with their positive aspects like low cost, nonabrasive nature, low density, good thermal characterise, superior energy recovery and bio degradability. Hemp is an important fibre used for manufacture a variety of automobile parts, rope, yarn, household application etc. Therefore, researchers are investigating new zones for utilization of hemp fiber as in reinforcement polymer matrix composite (PMC). Kevlar fibre is used for hybridization purpose. NaOH treatment is used for improve the adhesion strength between the matrix and hemp fibre. The natural filler (palm and coconut shell powder 75–150 µ) materials are being added to increase the mechanical interlocking property and also the bonding strength between matrix and fibre. In this research, the hybrid natural fibre composite was developed by Hemp/Kevlar/filler. Four types of specimens were developed in various different combinations (i.e. 0, 5, 7.5, and 10%) of filler. The size of the filler material and fibre was measured using scanning electron microscope. The trimming (machining) of the composite is very challenging to attempt using conventional machining processes. Therefore, non-traditional machining process i.e. abrasive water jet cutting was attempted. For trimming (machining) of polymer composites, Abrasive Water Jet Machining (AWJM) is widely employed in manufacturing industries. In the current research, kerf tapper, surface roughness (Ra) and the material removal rate (MRR) were examined under the influence of input factors such as Jet Pressure, nozzle Speed and Stand of Distance (SOD). Taguchi L9 orthogonal array based experimental study conducted. From the analysis, the nozzle speed was found the most significant factor. But, the jet pressure was always influenced by kerf wall inclination. The SEM image has been shown fibre pull out, filler distribution in a matrix and helps to understand the surface morphology of the fractured surface during trimming (machining).
S. P. Jani, A. Senthil Kumar, M. Adam Khan, M. Uthayakumar

Surface Engineering of Tungsten Carbide Tool Material by Nano and Microcrystalline Diamond Coatings

Abstract
Diamond is generally accepted as a material with individual properties such as superlative hardness, low coefficient of friction and very high thermal conductivity. Synthetic diamond can be achieved in the form of thin and thick films using experimental chemical vapor deposition (CVD) methods. Cemented tungsten carbide (WC–Co) is the commonly used tool material with high hardness (~18 GPa) and high elastic modulus (~550 GPa) and, also compatible to the growth of synthetic diamond films. Presently, synthetic diamond coatings have been widely used on carbide cutting tools from long time to prevent the abrasive wear occurred on conventional tools. Based upon the size of the grains, synthetic diamond coatings are basically classified into nanocrystalline diamond (NCD) and microcrystalline diamond (MCD). In the work reported in the present chapter, smooth and adhesive thin NCD and MCD coatings were deposited on chemically treated tungsten carbide substrates using pre-determined process parameters in the hot filament chemical vapor deposition (HFCVD) method. Tungsten carbide with 6% Co is the mostly accepted grade of base material used for the successful growth of synthetic diamond films on its surface and, also to minimize the thermal residual stresses existing during the deposition and cooling down process between the interfaces of coating and substrate. Mostly, these thermal residual stresses are produced due to difference in thermal expansion coefficients between the coating and substrate. During deposition process, the process parameters such as methane concentration (%CH4/H2) and chamber pressure were controlled automatically using pre-programmed recipe for the growth of NCD and MCD films. The structural characteristics and quality of the synthetic diamond films were confirmed using X-ray diffraction and Raman spectroscopy techniques, respectively. The surface morphology was studied using a high resolution scanning electron microscope (HRSEM) and atomic force microscope (AFM). Moreover, the hardness measurement of coatings were done using a Berkovich nanoindenter. After that, a comparative evaluation between these two types of coatings was done.
Kaleem Ahmad Najar, Shah Aarif Ul Islam, N. A. Sheikh

Backmatter

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