December 22, 2009

Metals Class

بِسمٍ الله الرَحْمنِ اللرَحِيْم

Materials in this group are composed of one or more metallic elements (such as iron, aluminum, copper, titanium, gold, and nickel), and often also nonmetallic elements (for example, carbon, nitrogen, and oxygen) in relatively small amounts[1] that made one compound in nature.

Metals account for about two thirds of all the elements and about 24% of the mass of the planet. Metals have useful properties including strength, ductility(i.e., capable of large amounts of deformation without fracture), high melting points, thermal and electrical conductivity, stiffness and toughness which accounts for their widespread use in structural applications. From the periodic table, it can be seen that a large number of the elements are classified as being a metal. A few of the common metals and their typical uses are presented below.

Common Metallic Materials
  • Iron/Steel - Steel alloys are used for strength critical applications
  • Aluminum - Aluminum and its alloys are used because they are easy to form, readily available, inexpensive, and recyclable.
  • Copper - Copper and copper alloys have a number of properties that make them useful, including high electrical and thermal conductivity, high ductility, and good corrosion resistance.
  • Titanium - Titanium alloys are used for strength in higher temperature (~1000° F) application, when component weight is a concern, or when good corrosion resistance is required
  • Nickel - Nickel alloys are used for still higher temperatures (~1500-2000° F) applications or when good corrosion resistance is required.
  • Refractory materials are used for the highest temperature (> 2000° F) applications.

Metal have a good properties in their use because of their atomic structure. Atoms in metals and their alloys are arranged in a very orderly manner, and in comparison to the ceramics and polymers, are relatively dense.

The key feature that distinguishes metals from non-metals is their bonding. Metallic materials have free electrons that are free to move easily from one atom to the next (electrons are not bound to particular atoms). The existence of these free electrons has a number of profound consequences for the properties of metallic materials. For example, metallic materials tend to be good electrical conductors because the free electrons can move around within the metal so freely.

Furthermore, the structure of metals the types and applications of metals and their alloys are discussed in next post. Insya Allah.

  1. The term metal alloy is used in reference to a metallic substance that is composed of two or more elements.

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