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PROPERTIES OF MATERIALS - 1

V. Ryan © 2005 - 2009

 

When studying materials and especially when selecting materials for a project / design, it is important to understand key properties. The most important properties are outlined below.

 

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STRENGTH  

The ability of a material to stand up to forces being applied without it bending, breaking, shattering or deforming in any way.

Our technology technician (Ed) demonstrates the ‘strength’ of a material by performing a hand stand on a strong piece of timber (wood). It does not bend even under his weight. He has eaten pies and drunk a large amount of beer for twenty years and yet the strong material does not bend, flex or deform (change shape) in any way.

 

   
ELASTICITY  

The ability of a material to absorb force and flex in different directions, returning to its original position.

Our technology technician demonstrates the ‘elasticity’ of a material by springing up and down on a piece of steel rod. Do not try this at home as an accident may result. Ed our technician is an expert at demonstrating this property as it is his hobby.

 

PLASTICITY  

The ability of a material to be change in shape permanently.

Our technology technician and his twin brother demonstrate the ‘plasticity’ of a molten aluminium by pouring it into a mould. Once the aluminium has cooled down, it can be removed from the casting sand. It has a new shape.

Our technician is often seen scavenging in dust bins after aluminum drinks cans. He then melts them down to form blocks (ingots) of aluminium to sell to scrap metal dealers.

 

   

 

   
DUCTILITY  

The ability of a material to change shape (deform) usually by stretching along its length.

Our technician stretches the lead above his head. As it stretches if deforms (changes shape).

Ed thinks he is a strong man, little does he realise that lead is a very soft metal and stretches very easily. He performs these tricks in local pubs in an attempt to pass himself off as a ‘hard man’.

 

   
TENSILE STRENGTH  

The ability of a material to stretch without breaking or snapping.

Our technology technician demonstrates ‘tensile strength’ by stretching a piece of steel until it snaps. Ed thinks he is incredibly strong. However, his friends at work have substituted a sausage in place of the steel.

 

   
 
   

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