An alloy is a stable metallic substance consisting of two or more metals, although it may in some instances also contain non-metals. Manufacturers produce alloys by mixing molten base metals -- the elements that will make up the most significant portions of particular alloys -- with molten supplemental elements. The elements fuse, forming a substance that takes on properties of both. Manufacturers use the process of alloying to achieve certain characteristics in metals, both for industrial and other purposes.
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The first alloy came into use during the Bronze Age, the beginning of which occurred in 3500 BCE. Made of copper and tin, early humans used bronze for 2,000 years before developing more complex furnaces to produce iron tools and weapons. During the Bronze Age, it became the material of choice for weapons used by nobility, royalty and pharaohs.
Aluminum is not a very strong metal, but its conductive qualities make it useful for a variety of applications. For this reason, manufacturers mix aluminum with other metals to strengthen it, forming several different aluminum alloys.
Alloys using aluminum include alnico, which contains nickel, iron and cobalt; magnalium, which contains magnesium and duraluminium, also known as duralumin and duralium, which contains copper and, in some instances, magnesium and manganese. While manufacturers use alnico in the production of magnets, they use magnalium primarily in instruments. Duraluminium is often a component in car and aircraft engines.
The element copper is prone to oxidation, which makes it surface turn a dull, pale-greenish color. To prevent oxidation, and to increase its strength, manufacturers fuse copper with several different elements. One of the most common copper alloys is brass, which contains approximately 20 percent zinc.
Manufactures often use the alloy for decorative items such as jewelry, as well as for nuts and bolts. Another common copper alloy is bronze, which contains about 10 percent tin. Nowadays, people commonly use bronze for making coins, statues and, as with copper, decorative items.
The most well-known alloy of iron is steel, which can contain from 0.5 percent to 1.5 percent of carbon as its supplemental element. The carbon helps prevent the iron from rusting, and makes it stronger. People use the material widely in construction, such as for making screws, nails and beams for buildings and bridges.
A variation on the alloy is stainless steel, which also contains nickel and chromium in addition to carbon. These elements help keep the metal shiny and intensify its resistance to corrosion. Manufacturers use stainless steel in a variety of different applications, such as for building tools, eating utensils, furniture and appliances such as refrigerators and ranges.
As a soft metal, pure gold is easy to work. For this reason, jewelry makers often mix it with other elements to increase its strength. The most common gold alloys include yellow gold, which contains copper, silver -- and in some instances cobalt -- and white gold, which contains copper, zinc, nickel and, in some instances, palladium. All types of jewelry, such as rings, bracelets, necklaces and earrings consist of both these alloys.