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I will talk about how alloys are made. Alloys are made by melting two or more different elements and mixing them. At least one of the elements that are used to make alloys is a metal. There are manykinds of alloys. The ones that I am going to talk are: bronze, steel, brass, electrum and pewter.

Bronze is made up of copper and tin. But we can also add to the bronze metals like silicon,phosphorus, aluminium and manganese. First bronze was made up of copper and arsenic, and they form arsenic bronze. In the 3rd millenium BC, the arsenic was changed into tin. Bronze with tin is stronger andless harmful than arsenic bronze. Bronze is normally made up of 88% of copper and 12% of tin. There are other types of Bronze like: Alpha bronze (4-5% of tin and 95-96% of copper), architecturalbronze (3% of lead, 57% of copper and 40% of zinc), bismuth bronze (30% of nickel, 5% of lead, 12% of zinc, 52% of copper and 1% of bismuth), etc.

Steel is made up of iron and carbon. We can also addto the steel metals like chromium, manganese, tungsten and vanadium. The first known production of steel was found in Anatolia, approximately 4000 years old. Now, to make steel we have to smelt theiron ore into a pig iron in a blast furnace. There are many kinds of steel like: carbon steel (iron and carbon), maraging steel (iron and nickel), stainless steel (iron and chromium), etc. There are twotypes of carbon steel: low-carbon steel (0,05-0,29% of carbon) and high-carbon steel (0,30-1,70% of carbon).

Brass is made up of copper and zinc. The brass has been used since the prehistory. Butthe first brass alloy known was from China in the 5th millenium BC. The brass in the early years had approximately 5-15% of zinc. Approximately in the Roman period, the people used a process calledcementation to make brass. But since the 16th Century, we use speltering to make brass. There are many types of brass like: beta brass (45-50% of zinc), high brass (65% of copper and 35% of zinc),...
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