The purpose of alloying is to change and improve material properties such as toughness, strength, hardness, etc. Pure metals are usually not suitable for practical use. Some properties of metals such as durability, hardness, etc. can be improved by adding one or more other metals to it and producing an alloy. In general, alloys are much more useful than their raw materials. For example, pure aluminum is a light metal with not very high resistance، But by adding copper and magnesium to it and producing a new alloy of these 3 materials, an alloy with far higher strength than each of the previous metals is created. Due to their low weight and high strength, aluminum alloys are widely used in aircraft, spacecraft and rocket industries, as well as vehicles. Brass is an alloy made from a mixture of molten copper and zinc, and bronze is an alloy made from a mixture of molten copper and tin.
Alloys are not always formed from the combination of two or more metals, but it is possible to create resistant alloys with high strength from the combination of one or more metals with one or more non-metals. Steel is one of the most famous alloys that is formed from the combination of iron, which is a metal, with carbon, which is a non-metallic substance. The term steel is used for iron alloys that have between 0.025 and about 2% carbon. Alloy steels are often combined with other metals. The properties of steel depend on the percentage of carbon in it, the heat treatment done on it and the alloying metals in it. Alloy steels become stainless steel by adding chromium metal to them. Due to the percentage of carbon used in them and their strength, alloy steels have many uses in many materials and industries, from making cutlery to making wires and pipes, as well as being used in construction, bridge building and …
According to the metal used in it, alloys are divided into ferrous alloys and non-ferrous alloys.
Ferrous alloys are alloys in which the base metal is iron, and steel is one of the most important and famous types of metal alloys.
Non-ferrous alloys are alloys in which the base metal is a metal other than iron, such as bronze, brass, etc. Today, most of the metals we use are in the form of alloys, and it is rare to use pure metals in consumables. Even precious metals such as gold and silver are made into alloys and used. Adding cheap metals to gold and silver not only does not reduce their value, but also adds better properties to them, including resistance to wear.
Brasses are alloys of copper and zinc, which are divided into yellow brass, red brass, lead brass, silicon brass, tin brass and nickel brasses based on the changes in appearance and color.
Brasses or alloys of copper and zinc have the following properties from the point of view of the network of solid solutions of copper and zinc:
If the amount of zinc metal is less than 50%, the alloy is in the beta region, and the amount of zinc metal must exceed 50% for the formation of the gamma network. For this reason, the amount of zinc metal in rice is always less than 47%, and the color of rice depends on the amount of zinc.
If the brass consists only of alpha solid solution, then the mechanical properties increase with the increase of zinc metal, then decrease again with an excess of zinc. If the brass is composed of alpha and beta networks, the percent deformation continues to decrease while the hardness continues to increase.
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