1. An alloy is a homogeneous mixture of a metal with one or more other elements which are usually other metals. The purpose of alloying is to alter or improve the chemical and physical properties of a metal in order to use the alloy for a specific function. For example, alloys can be made to improve a metal's hardness, magnetism, tensile strength, and corrosion strength. The harder alloy can replace the use of another metal that does not have the required and ideal characteristics for a particular function.2.Iron alloy: mild steelCopper alloy: cupronickelComposition Mainly iron with < 0.2% carbon . 70% copper and 30% nickelUse for making car bodies Sea water pipesBecause the alloy of the metal makes it more suitable for use. By adding carbon, steel becomes harder, stronger, and is more resistant to corrosion than iron. Steel is malleable and therefore can be easily welded and shaped into the shapes needed to create car bodies. The cost of steel is low compared to metals such as aluminum, which can also be used for car bodies but is expensive. Steel is plentiful and cheap. These properties make steel a suitable material for car bodies. By alloying copper – with the addition of nickel, cupronickel alloys have improved strength and corrosion resistance. The alloy's high resistance to bio-fouling and corrosion, especially seawater, makes it a suitable material for making pipes for seawater systems.3. CHRONOLOGY OF METAL DISCOVERY4. Copper, gold and silver were some of the first metals that man discovered and used. The order of discovery is closely connected with their reactivity. The less reactive the metal, the easier it is to extract since it requires less energy, and in the middle of paper, people didn't have the resources or technology to mass produce it. Aluminum was very expensive due to the difficulty of obtaining it pure and was even more expensive than gold ($115 per pound = 454 grams). The softness of aluminum limited its extensive use. The softness of the metal limited it to applications such as jewelry and tableware. In 1906, a German metallurgist, Alfred Wilm, created an aluminum alloy and discovered a method to strengthen it. He combined a small amount of copper with aluminum, heated it to a high temperature, and cooled it rapidly. The aluminum alloy was softer than before, but became considerably stronger after a few days due to precipitation hardening. Lightweight, easily sculpted, and strong, aluminum was used extensively in the 20th century and became valuable in aviation, engineering, and other transportation.