Metallurgy is a domain of materials science and engineering that studies the physical and chemical behaviour of metallic elements, their inter-metallic compounds, and their mixtures, which are called alloys. Metallurgy encompasses both the science and the technology of metals. Metallurgical Science is a discipline concerned with extracting metals from their ores, and the development, production and use of metallic materials. Metallurgical engineering is based on the principles of science and engineering. It may be divided into process metallurgy, which is concerned with extracting metals from their ores to make refined alloys, and physical metallurgy, which involves the shaping, alloying, heat treatment, joining, corrosion protection and testing of metals. Metallurgy concerning the extraction of metal from ore or metal compounds is a significant industry that supplies metallic material with extraordinary properties for applications in many fields.