A composite material is made by combining two or more materials that are mutually insoluble by mixing or bonding them in such a way that each maintains its integrity. Some composites, plastics modified by adding rubber particles, plastics reinforced by chopped glass fibers, cemented carbides, and concrete. These and many other composite materials consist of […]
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Ceramics and glasses are solids that are neither metallic nor organic (carbon-chain based) materials. Ceramics thus include clay products, such as porcelain, china, and brick, and also natural stone and concrete. Ceramics used in high-stress applications, called engineering ceramics, are often relatively simple compounds of metals, or the metalloids silicon or boron, with nonmetals such
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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
Properties of Nonferrous Metals Quenching and tempering to produce a martensitic structure is the most effective means of strengthening steels. In the common nonferrous metals, martensite may not occur; and where it does occur, the effect is not as large as in steels. Hence, the other methods of strengthening, which are generally less effective, must
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
Alloying of Metals Approximately 80% of the one-hundred-plus elements in the periodic table can be classed as metals. A number of these possess combinations of availability and properties that lead to their use as engineering metals where mechanical strength is needed. The most widely used engineering metal is iron, which is the main constituent of
Deformation of Solids There are three basic types of deformation: elastic, plastic, and creep deformation. Elastic deformation is discussed next, and this leads to some rough theoretical estimates of strength for solids. Elastic Deformation Elastic deformation is associated with stretching, but not breaking, the chemical bonds between the atoms in a solid. If an external
Metals and ceramics are composed of aggregations of small grains, each of which is an individual crystal. In contrast, glasses have an amorphous or non-crystalline structure. Polymers are composed of chainlike molecules, which are sometimes arranged in regular arrays in a crystalline manner. Basic Crystal Structure of Materials The arrangement of atoms (or ions) in
Types of Material Failure A deformation failure is a change in the physical dimensions or shape of a component that is sufficient for its function to be lost or impaired. Cracking to the extent that a component is separated into two or more pieces is termed fracture. Corrosion is the loss of material due to
Diffusion in Solids A flow process that governs the movement of atoms and molecules in solids is called diffusion. The atoms and molecules change their position under influence of thermal energy, stress gradient, electric and magnetic field gradients, and concentration gradient. The process of diffusion can be easily visualized in a liquid but is more