Adding carbon to steel makes it harder and stronger. Is this true for all metals? Could you add carbon to titanium or vanadium to make them even harder and stronger?

 

On the contrary, why adding sulphur to metal to give a softer metal?

I could imagine there's no chemical reaction.

No there is no chemical reaction involved. The hardness is achieved due to the structure and packing of Fe itslef. I do not think you can make generic statements about carbon hardening metals though, as metals would have different types of structures and varied atomic sizes.

"I do not think you can make generic statements about carbon hardening metals though, as metals would have different types of structures and varied atomic sizes."

 

Yeah. Some metal's do usually get other rather interesting things added to them, though. A good example is aluminum or titanium.

Carbon and silicon in Iron will make them harder and more resistant to wear, Iron with carbon in is known as Steel at that point.

 

other metals such as Alu and Gold and Silver have traces of copper added for hardness.

Alu with copper is known as Duralumin it`s used in aircraft too, but it will "work harden" also making ragular check-ups for cracks necesary.

 

a topic like this can go on forever though. Heat treatment is also important as that affects the metalic crystal size and thus its properties

 

this seriously could go on forever!

Yep, take a chemical analysis of any nowadays steel and got your work cut out for you. Sure the term "stronger" is something got to be careful here ... add enough carbon and we're talking about cast irons, the other end resembling more glass than steel. Hardening mechanisms of metals might be an interesting topic itself.

yeah, "Harder" can be taken to mean a few things to the un-initiated, harder usualy mean Scratch resistant, but is also synonymous with "Brittle" in many instances.

Case hardening with cardon is again a different story, the outside is still "brittle" but since it`s all made of one peice the inner part is still regualr steel so hitting it with a hammer wont effect it, whereas cast iron will shatter as the marzites and crystal structure run throughout.

alloys of Chromium and Vanadium again make a different kind of steel (stainless) and there are gradients of stainless steel too...

bamboo is stronger than steel,

and spider webbing is strong than That! )

 

 

your point?

Is it possible to make an alloy ( mixed with carbon also called alloy?) harder than diamond?

if by "Harder" you mean it will out perform Diamond in a scratch test, then non that I`m aware of, no.

Some diamond like get to a same order but still not too close as far as I know (they may have better other properties, like tribological ones, but not harder). For example DLC coatings used widely commercially (diamond like carbon) can have a hardness of about 2k HV while diamond is typically closer to 10k.

and some metal Carbides and Nitrides are very hard too, but non as hard as diamond.

Yeah, I've somehow gotten the idea for diamond being the "ultimate" and whether you can even go past it being questionable ... with the fully covalent 3D bonding and resulting extreme stiffness of it.