What Causes Variation in Ductility of Pure Metals?

[eeeeediot]

What makes some pure metals more ductile than other pure metals?

I know ductility is defined as the ability of a material to be drawn into a wire, and one measurement of it is the percentage elongation from a tensile stress test. But does anyone know what is going on at an atomic level when the metal is being plastically deformed that makes some metals more ductile than others?

Right now I think it might be the density of dislocations or other defects, but surely that can't account for such large variations in behaviours?

Any help would be appreciated.

EDIT: I removed the parentheses, but I'm sure I read somewhere that Aluminium is more...
and by pure metals I mean not alloys.

 

[Gokul43201]

What makes some pure metals (like Aluminium) more ductile than other pure metals (like Copper)?

This isn't even true! Copper is among the most ductile metals there is (55% strain at yield).

If you erase all the text inside parentheses and leave the question reading "what makes some pure metals more ductile than others?" it would be a lot more sensible.

Dislocation density is definitely important, but I think the question is referring to pure metals in the sense of both lack of impurities as well as lack of defects. What's the primary difference between pure Fe and pure Cu, from a metallurgical point of view?

 

[eeeeediot]

Anyone got any ideas or know any websites that have detailed information about this subject?