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ALLOYS

V. Ryan 2010

 

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DEFINITION: An alloy is a metal (parent metal) combined with other substances (alloying agents), resulting in superior properties such as; strength, hardness, durability, ductility, tensile strength and toughness. The parent metal is the majority of the alloy. For example, mild steel is 0.1 - 0.3% Carbon and 99.9 - 99.7% Iron.

Alloys are sometimes described as a mixture of two or more metals. However, this is misleading, as often alloys are composed of just one metal, as well as other non-metal elements. Cast iron is an example, as it is a combination of iron (metal) and carbon (non-metal).

Metal alloys have specific enhanced properties compared to their ‘parent’ metals.
For example, steel. Steel is itself an alloy of iron and carbon. Iron is a very brittle metal, likely to break or snap if it receives a sudden blow/shock. Adding the alloying agent carbon, gives the new alloy the property of toughness and tensile strength. Steel can be used in the construction industry for bridges and large buildings. A bridge manufactured only from the parent metal, iron, would eventually collapse due to its inability to absorb shocks/blows. The table below gives three alloying elements that can be added to the alloy steel, to further improve its physical properties.

 
 
 
 
BRIDGE MANUFACTURED FROM THE ALLOY, STEEL
 
The steel bridge possess the property of toughness and tensile strength, alloying it to absorb the vibrations caused by cars and lorries. The bridge will last a hundred years or more, if maintained properly.

BRIDGE MANUFACTURED FROM THE METAL IRON
 
The iron bridge below, shattered due to the vibration caused by traffic crossing from one side to the other. Iron does not possess the property of toughness or tensile strength to the required standard. Therefore, it will not absorb vibration.
 
 
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