1.2 METALS GENERAL CHARACTERISTICS OF METALS General description of materials There are thousands of materials used in engineering applications and most of them belong to one of the three main classifications: Metallic Ceramic . Polymeric Additionally, different materials can be combined to create a . Materials are often organized into groups based on their chemical composition or certain physical or mechanical properties; composite materials are often grouped by the combination of materials or how they are together: composite material arranged DO What metals are used most in engineering? 1 MORE An alloy is a substance made by melting two or more elements together, and at least one of them is a metal. The components of alloys cannot be separated using a physical means. 1 MORE Examples of refractory metals are: molybdenum, tungsten, chromium, iridium, rhodium. 2 MORE Superalloys are high-strength, complex alloys that are resistant to high temperatures, severe mechanical stress and have high surface stability. They are used, for example, in the turbine section of jet engines. 3 Metals Metals represent about two-thirds of all the elements and about 24% of the mass of the planet. Metals have useful properties including strength, ductility, high melting points, thermal and electrical conductivity, and toughness. Some of the common metallic materials and their typical uses are: : Steel alloys are used for critical strength applications. Iron/Steel : They are used because they are easy to form, easily available, inexpensive, and recyclable. Aluminium and its alloys : They have properties like high electrical and thermal conductivity, high ductility, and good corrosion resistance. Copper and its alloys : Titanium alloys are used for strength in higher temperature (∼540°C) applications, when weight is a concern, or good corrosion resistance is required. Titanium : Nickel alloys are used for even higher temperature (~810-1100°C) applications or when good corrosion resistance is required. Nickel : They are used for the highest temperature (>1100°C) applications. Refractory metals
