Definition: The behavior of materials under fluctuating and reversing loads (or stresses) is known as fatigue. This behavior is different from that under the steady load. Fatigue is, however, not a dynamic effect. The rate of loading is usually not a factor in fatigue behavior. Fatigue behavior is experienced by all materials whether metals, plastics, […]

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

Classification of Solids Solids, on the basis of their structures, may be classified as: Examples of such solids are as under: Metallic solids: Na, Cu, Zn; compounds such as borides, hydrides, nitrides, carbides etc. formed by transition elements. Ionic solids: NaCl, Na2SO4, MgAl204, calcite (CaCO3), magnesia (Mg0), Zincblende (or sphalerite) ZnS having FCC structure, and

Crystal Structure of Solids The study of geometry and structure of solids is a science known as crystallography. X-rays and microscopes have substantially contributed to this area. The atoms and molecules are held together by chemical bonds in the solids. The orientation, periodicity, and symmetries of atoms and molecules vary widely. The arrangement of atoms