No, but a very, very fine powder.
The reason why two freshly broken pieces of something don’t stick back together is actually unique to the kind of atmosphere we have on Earth. Our atmosphere bonds with the freshly exposed surface (oxidisation), and you need a tremendous amount of force on both pieces to “squeeze” the atmosphere back out of the crack, if at all.
If it wasn’t for air, everything would cold-weld together, whether you wanted it to or not.
Interestingly, this was a significant problem for some vehicles and satellites we sent up in space, where various metal components would fuse together.
So, back to your original question, why a powder? Because the particles would be oxidised. So what if we did it in a vacuum? Well.. it would just sort of stick back together into a solid clump like what you started with, but significantly weaker because of the seriously messed up lattice.
To turn it into a liquid, you need lots and lots of heat. (~3873K)
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