Fundamentals of Materials Engineering- A Basic Guide

This book discusses the study of microstructures of various materials and their classifications. It also focuses on different types of chemical bonds and the arrangement of atoms in materials. It also explains how the defects or imperfections in materials control their properties and explains the different types of strengthening mechanisms used to improve the strength of materials. This book also discusses the characterization methods used to study the mechanical properties, stress-strain curves, basics of polymers, their types, properties, and applications. Basics of powder metallurgy, mechanism of sintering, advantages and dis-advantages of powder metallurgy were explained in detail. Basic principles of corrosion, types, mechanism, and corrosion control methods, fundamentals of composite materials, their types, properties and applications are discussed in this book.

Do you know all the materials are made up of atoms? And there are different types of atoms named as elements? Have you ever wondered why an atom consists of electrons, protons, and neutrons? Do you know the number of electrons in the outer shell depicts the number of atoms present? Can you tell me why metals are ductile compared to hard and brittle ceramics? Why ductile iron becomes harder when we add a small amount of carbon? Why some materials act as conductors of heat and electric current and some are insulators [1]? To understand all these concepts one should learn the atomic structure, chemical bonding, structure of amorphous and crystalline materials. The present chapter describes all these concepts in a very simple way.

Properties of most of the materials are tremendously influenced by some imperfections or defects. These imperfections greatly alter the mechanical, electrical, surface, chemical, and thermal properties of materials. Therefore, one should have complete knowledge of defects or imperfections. The mechanical properties of pure metals greatly change when they are alloyed; for example, steel (a combination of iron and 0.1% carbon) is much harder and stronger than pure iron. Bronze (20% tin and 80% copper by mass) produces a much harder and sharper weapon than pure tin or pure copper. Jewelry gold (pure gold and 5% copper by mass) is a much harder, lustrous, and durable gold than pure gold.

The mechanical properties of a material reverberate the correlation between its response and deformation to an applied load. Some of the very important mechanical properties are ductility, strength, stiffness, and hardness. These properties can be studied by using various instruments available in the metallurgy or mechanical engineering laboratories. The mechanical properties of materials mainly depend upon the factors like nature of the applied load, its duration, and environmental conditions. The applied load may be tensile, compressive, or shear in nature; and its magnitude may be constant or may fluctuate continuously with time. Another important factor is time or duration, and it may vary from a fraction of a second to many years. Some of the important tests used to study mechanical properties are, creep test, tensile test, compression test, fatigue test, hardness test, impact tests, etc.

In the present chapter, we have discussed the classification of polymers, structure, properties, fabrication process, and polymerization mechanism. Generally, polymers are made up of a series of molecules joining together and the average molecular weight of chains ranges from 10,000 to more than one million. The process of chemically joining the monomers together to create giant molecules is called polymerization. In polymers, atoms are joined together by a strong bond called covalent bonding. Many of the polymers are organic (carbon-based polymers) and inorganic (non-carbon based polymers like polysiloxanes, polyphosphazene, polysilanes, etc.).

In this chapter, we have discussed the basic principles of Powder Metallurgy, preparation of metal powders and alloy powders by different powder metallurgy techniques and also discussed the applications of powder metallurgy. This chapter enables the student to learn how powder metallurgy has emerged as one of the superior methods to prepare metals and alloys; and the advantages and disadvantages of powder metallurgy. The use of iron metal powders was started in way back 3000 BC by Egyptians to prepare their tools for various purposes. But, the modern era of powder metallurgy started when electric bulbs were discovered, and the tungsten lamp filaments were developed by Edison. Any components can be prepared from pure metals, alloys by powder metallurgy routes. Materials like nickel, aluminum, iron, copper, brass, titanium, bronze, steels, and refractory metals are prepared by the powder metallurgy method.

In this chapter, we have discussed the basic principles of corrosion, factors affecting corrosion, effect of corrosion, types of corrosion, mechanism of corrosion, how to control corrosion, anodic and cathodic coating. This chapter enables the student to learn the fundamentals of corrosion and its effects, disadvantages of corrosion. Corrosion is the process of deterioration of metals as well as alloys in the presence of an electrochemical or chemical environment. It is an irreversible chemical reaction that results in the dissolution of the material. It also deals with the small visual change to complete failure of giant technical systems and causes a big blow to the economy and even hazard to people.

In this chapter, we have discussed the basics of composite materials, types, properties, and applications. Students will learn the fundamentals of composite materials and their importance in many engineering fields. Composite materials can be defined as “the combination of a hard and a soft material” or “these are the materials composed of different parts with specific ratios”. This chapter comprises of the advantages and disadvantages of composites and also focuses on different fabrication methods of preparing composites. Fundamentals of nanocomposites and their recent improvements are also added in this chapter.