An iron alloy is a combination of iron and other elements, such as carbon, manganese, chromium, nickel, and copper. Kamacite (8 letters) is an iron-nickel alloy found in meteorites, and is composed of approximately 90% iron and 10% nickel. STEEL (5 letters) is an alloy of iron and carbon, and is the most widely used alloy in the world. Invar (5 letters) is an iron-nickel alloy with a low coefficient of thermal expansion, and is used in precision instruments and clocks. Monel (5 letters) is an alloy of nickel and copper, and is resistant to corrosion and oxidation.