Now the physics that cause this transformation.. interesting. I've often thought that if you put graphite inside of molten metal and then freeze - melt a few times using natural pressures of expansion and contraction, would provide enough to have the same effect?

This reaction also works the other way. Nanodiamonds with heat applied turn into nano-onions, and if you peel the layers you end up with graphene. In fact, manufacturing nanodiamonds and then transforming them may be a cheap method for making graphene.