Metallurgy Topics or Metal Technology +

(terms about the science and technology of metals and metal processing)

metal, metals; metallic element, metallic elements
1. Any of a class of elements that generally are solid at ordinary temperatures, have a grayish color and a shiny surface, and will conduct heat and electricity.

In a pure electrolytic solution, a metal will form positive ions.

Metals constitute about three-fourths of the known elements and can form alloys with each other and with nonmetals.

Common metals include copper, gold, silver, tin, iron, lead, aluminum, and magnesium.

2. An alloy is a mixture composed of the previously listed-common metals.
metallic bond, metallic bonding
In chemistry, a force that holds atoms together in a metal, formed by the attraction between positively charged metal ions and mobile free electrons surrounding them. This accounts for many of the characteristic properties of metals and alloys.
1. A chemical element having both metallic and nonmetallic properties; such as, boron or silicon.
2. A nonmetallic element that can combine with a metal to produce an alloy.
metallurgical coal
A term for coking coal and pulverized coal used in making metals and alloys.
metallurgical coke
A low-sulfur coke, suitable for the smelting of iron ores.
metallurgical grade silicon
Silicon that is prepared by the heating of high-purity silica in an electric arc furnace at temperatures over 1900 degrees Centigrade using carbon electrodes, producing a material that is at least 99% pure.
metallurgical or materials engineers
1. Engineers who develop methods to process and convert metals and other materials into usable forms.
2. Technology is developed to produce ceramic substances, new compounds, and metal alloys for use in computers, spacecraft, and industrial equipment.

These engineers develop new materials for applications that require exceptionally high strength and heat resistance and they also determine how materials fail, using instruments; such as, microprobes, scanning electron microscopes, and X-ray diffraction and examine failed, broken, or contaminated materials.

1. The science and technology of producing metals, which includes extraction, alloying, and hardening.
2. The study and science of extracting and refining metals from their ores and shaping them into useful products.

Metallurgy is One of the World's Oldest Arts

  • Iron samples have been discovered dating back to 4000 B.C.
  • The art of iron making was well known to the ancient Egyptians by the time of Ramses II (1290-1223 B.C.).
  • Most of the advances before the fifteenth century in the field of metallurgy were introduced to Europeans by Arab craftsmen.
  • Once established in Europe, metallurgy, specifically iron production, suddenly expanded and iron became essential at the time of the Industrial Revolution.
  • The invention of the Bessemer process in 1856, by British engineer Henry Bessemer, made steel affordable and led to the nonstop production of steel-related products.
  • Products such as planes, trains, automobiles, and machines of every kind all require the use of an art and basic technology that started almost 6,000 years ago.
—Compiled from information in the
Encyclopedia of Science and Technology; Editor, James Trefil;
Routledge Publication; New York; 2001; page 313.
metal-organic chemical vapor deposition, MOCVD
A process of producing materials for semiconductors, including photovoltaic material, in which a surface layer is produced by the deposition on a substrate of a volatile organo-metallic compound; such as, methyl, which is transported to the surface through the gas phase at elevated temperatures.
physical metallurgy
1. The properties of metals and their applications.
2. The adaptation of metals for everyday use.
3. Concerned with the ways metals and alloys are worked mechanically, their heat treatment, and their testing.

Physical metallurgy begins with the dressing of ore, using physical methods; such as, crushing, grinding, and separation by gravity to separate the various minerals that are found in a specific ore.

The roasting, smelting, and other high-temperature chemical reactions.

Pyrometallurgy has the advantage of giving fast reactions and yielding a molten or gaseous product that can easily be separated from unwanted components.

The extracted metal may need further refining or purifying; electro-metallurgy can be used again at this stage. The molten metal that is produced may then be cast by pouring it into a mold or forming it into ingots.

titanium alloys
Titanium is particularly important for providing extreme durability (about the same as steel) and at very light (half the weight of steel), both considerations in the construction of high-performance aircraft.

However, the alloys used in jet and rocket engines; especially, in areas of intense heat and stress, are usually nickel-based or cobalt-based.

Alloys are often far less conductive of electricity and less reactive to living bodily tissue than pure metal, which makes them ideal for use in prosthetic devices, heart pacemakers, and in dentistry.

—Compiled from information located at the
Encyclopedia of Science and Technology; Editor, James Trefil;
Routledge Publication; New York; 2001; page 33.
A method of joining two metals by fusing them by one or another solid-state process.

Since most metal surfaces are covered by a layer of oxide or a similar material, the first step in welding is to remove that layer or to form a new surface by cutting or deforming the metal to be welded.

In gas welding, an oxyacetylene or oxyhydrogen torch is used to create the weld. Arc welding uses the heat that is generated by an electric arc to join the metals. Atomic-hydrogen arc welding combines gas welding and arc welding.

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