Having produced and formed a metal, it is necessary to ensure that it performs well during service. A major consideration in this is corrosion. This involves loss of material from the metal’s surface and can be divided into two processes: dry oxidation and wet corrosion. Oxidation and Corrosion of Metals Dry Oxidation The earth’s atmosphere …
Crystal Structure of Solids Many construction materials, particularly metals and some ceramics, consist of small crystals or grains within which the atoms are packed in regular, repeating, three-dimensional patterns giving a longrange order. The grains are ‘glued’ together at the grain boundaries; we will consider the importance of these later, but first we will discuss …
Properties of Polymers Polymers are materials consisting of long-chain molecules formed primarily by carbon-to-carbon bonds. Examples include all materials commonly referred to as plastics, most familiar natural and synthetic fibers, rubbers, and cellulose and lignin in wood. Polymers that are produced or modified by man for use as engineering materials can be classified into three …
Iron-based alloys, also called ferrous alloys, include cast irons and steels and are the most widely used structural metals. Steels consist primarily of iron and contain some carbon and manganese, and often additional alloying elements. They are distinguished from nearly pure iron, which is called ingot iron, and also from cast irons, which contain carbon …
Polymerization | Processing of Plastics Materials derived from carbon are termed as organic materials. Range of organic materials is in thousands owing to vast variety of hydrocarbons and their derivatives. Organic materials may be natural or synthetic. Petroleum rubber wood coal biological fibers food etc. cotton flax are examples of natural organic materials. And oil …
Creep in Materials The permanent deformation (strain) of a material under steady load as a function of time is called creep. A very common observation, in which length of our waist belt increases after some duration, is due to creep effect. It is thermally actuated process, and hence is influenced by temperature. It is, however, …
Types of Dislocation in Crystalline Solids Line imperfections are called dislocations. There are two primary types of dislocations. These are: Edge Dislocations To understand an edge dislocation, consider a perfect crystal shown in Figure 1(a). Atoms (not shown in diagram) are located on each cross-point in it. A perfect crystal is free from dislocations. Now …
Imperfections in Crystalline Solids A perfect (ideal) crystal is a perfectly ordered arrangement of atoms at the points of infinite space lattice. Any departure from this idealized arrangement makes the crystal imperfect. A perfect single crystal is rarely available. Crystalline materials have real crystals. They are of finite dimensions. They have broken bonds at the …
Crystal Structure Analysis by X Ray Diffraction Structures of solids can be determined by various techniques. Out of these techniques, X-rays and microscopic studies have helped immensely in studying crystallography of metals. Therefore these two techniques are very popular. Hence X-rays will be discussed in this article and microscopy is discussed in another one. X-RAYS …
Miller is the name of a material scientist. Indices is plural of index. Miller indices are the styles to designate the planes and directions in the unit cells and crystals. Such designations become essential for investigations of various properties in different elements. In the most general way, Miller indices are expressed by (hkl) and no …