In its general, modern sense, metallurgy is the science that studies the chemical and physical properties of metals, including how they perform when used for culturally useful industrial purposes. The term often refers to the procedures used in extracting metals from ore, as well as to the processes related to metals purification and alloy production. It also refers to the craft of making culturally useful objects out of metal, or metalworking. The practice of metalworking has been carried out over thousands of centuries.
Evidence of this science and craft dates back roughly 6,500 years. Copper, tin, silver, and meteoric iron, which was used by the Egyptians to make weapons, all underwent some form of metalworking process in various ancient cultures. The first evidence of a standard metallurgy technology appeared during the Bronze Age, which started around 3,500 BC, when it was discovered that by heating and combining copper and tin, a bronze alloy could be created. The Iron Age began around 1,200 BC when the Hittites discovered how to extract iron from ore and work it to advance their cultural aims. Georg Agricola, considered to be the father of metallurgy, detailed ore mining and metal extraction procedures, as well as other aspects of the science, in his 16th century book, De re metallica.
Modern metallurgy is divided into two subtypes. Process metallurgy refers to the steps involved in producing metals, in most cases, from sulfides or oxides, and then refining them in their reduced form through electrolysis or selective oxidation of impurities. Physical metallurgy studies the structure of metals, based on their composition and treatment, and how this structure is related to their properties. It is also concerned with the scientific principles and engineering applications employed in metals fabrication and treatments, and how metal products hold up under their industrial usages.
Metallurgical engineers employ different forms of metals testing. In that way, they can make quantified assumptions about a metal's strength. These tests are meant to determine such properties as metal hardness, impact toughness, and tensile strength, to name of few.
In general, elemental metals, in their pure native form, are too soft for industrial uses. That is why the science of metallurgy tends to focus on the manufacture of alloys, in which metals are combined together or with non-metals. Steel and cast irons are examples of iron-carbon alloys. Aluminum, copper, iron, magnesium, and zinc are the metals that are used most, usually in their alloy forms.