why alloy is harder, stronger, less ductile and less malleable than its pure metal?

Question

provide illustrations if available

Answer 1

Steel an alloy of Iron. There are many varieties of steel with Iron as the chief constituent and some other constituents like Chromium, mangenese, carbon etc.

Answer 2

Alloy is a mixture of 2 or more metals. A pure metal have an orderly arrangement of atoms, hence when a force is applied, the layers of atoms will be able to slide over each other easily. Therefore, pure metals are malleable and ductile. However, an alloy have a mixture of 2 or more metals which disrupts the orderly arrangement of the atoms, hence when a force is applied, the layers of atoms will not be able to slide over each other easily(This actually causes alloys to be brittle) That is why alloy are harder,stronger,less ductile and less malleable than its pure metals.

Answer 3

All of the properties you mentioned are a result of limiting dislocation movement. Dislocations are imperfections in the crystal lattice and have an associated stress field (see first reference). Dislocations in pure metals can move relatively easily (see second reference). An alloy introduces a foreign atom into the lattice, which will have a preference on which side of the dislocation to be at. This means that it also has to move along with the dislocation, which is more difficult.

Hopefully the reference will give you some visuals as to what's happening in a material. It's difficult to write about. If you can get a basic materials science book, that would probably be best. Let me know if you need recommendations.

Answer 4

becasue alloys are mixed
the pure magnesium strips are really weak, but when oxidized, mixed with otehr metals etc... theyre strong, so it really is because theyre mixed with so many other metals, that they increase hardness..

hope this helps

Answer 5

9 carat gold as opposed to it's purer relative 24 carat gold.

See links....
http://www.24carat.co.uk/hardnessofgoldalloysframe.html

http://en.wikipedia.org/wiki/Gold#Applications