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Introduction
Alloys are materials made of two or more chemical elements, at least one of them a metal. Elements are added to an alloy to improve certain properties such as strength, hardenability and resistance to corrosion. Different elemental additions can result in very different properties between alloys. It is therefore important for alloy producers to understand the effects of each element when formulating an alloy for a specific purpose.
Common Alloying Elements
The most common alloying elements in steels are carbon, silicon, manganese, phosphorus and sulfur. Carbon is the most important element as it improves strength and hardenability of steel. It also makes it easier to heat treat steel. Silicon increases strength and is used to deoxidize steel. Manganese is an important deoxidizer and helps promote ductility in steel. Phosphorus helps improve strength and also increases wear and corrosion resistance. Sulfur increases machinability of steel.
Other alloying elements that are often used include nickel, chromium, molybdenum, copper, titanium and tungsten. Nickel is often used to add strength to steel and is found in many high strength alloys. Chromium increases oxidation and corrosion resistance and is found in stainless steels. Molybdenum increases strength and hardness and is used to form wear resistant alloys. Copper improves formability and strength in steels and is used in low alloy steels. Titanium strengthens metallic alloys and is often found in titanium alloys. Tungsten forms alloys with other metals and is used to increase hardness and wear resistance.
Effects of Elements on Properties
The addition of elements to an alloy can have profound effects on the mechanical, thermal and electrical properties. For example, adding nickel to steel can increase its strength, improve its formability and decrease its susceptibility to plastic deformation. Adding copper to steel can increase its electrical and thermal conductivity as well as its hardness. Adding chromium to steel can increase its resistance to corrosion and oxidation. Different elements have different effects on the properties which is why it is important for alloy producers to understand the effects of different elements when formulating an alloy for a specific purpose.
Conclusion
In conclusion, different elements are added to alloys for different reasons. Elements can have profound effects on the properties of an alloy which is why understanding the effects of each element is important for alloy producers formulating an alloy for a specific purpose. The most common alloying elements in steels are carbon, silicon, manganese, phosphorus and sulfur, while other elements such as nickel, chromium, molybdenum, copper, titanium and tungsten can also be added to enhance properties.
