Alloys Flashcards
What is the purpose of alloys?
They are made to improve the properties of metals for a specific application.
Why are alloys stronger than original metals?
In a pure metal structure, all the atoms are the same sized and packed closely together. (A regular arrangement of identical atoms). The layers of atoms can easily slide over each other making the metal soft.
However, alloys have different sized atoms due to there being more than one type of element. This prevents the layers of atoms from sliding over each other as easily which makes alloys harder and stronger.
Name three examples of alloys
Iron to steel/stainless steel (mixed with carbon and other metals)
Pure gold to alloy gold(mixed with zinc, copper and silver)
Shape memory alloys (nitinol)
Why is steel alloys more useful than iron?
They are stronger
Why is stainless steel more useful than iron?
It is corrosion (rust) resistant.
Why is gold alloys more useful than pure gold?
It is stronger
What is the purity of gold measured in?
Carats - 24 carats being the purest.
Fineness - 1000 parts per thousand being the purest.
What are smart materials?
A material with a property that changes with a change in conditions, eg temperature.
What is a shale memory alloy?
An alloy that returns to its original shape with a change in conditions, most often temperature.
Name an example of a shape memory alloy.
Nitinol - an alloy of nickel and titanium.
Name two uses of nitinol (shape memory alloys)
Repair collapsed arteries
Flexible spectacle frames
How can a shape memory alloy (nitinol) repair a collapsed artery?
A cool and squashed nitinol tube (stent) is slid into the damaged artery, and as it warms up in the body it returns to its original size, holding up the artery.
What are alloys?
A mixture of metals. They are often harder and stronger than original metals.
