NEXT BIG THING
When material in a molten phase is cooled very slowly, its atoms have time to organise themselves into a crystal phase. Each atom is in a position of mechanical stability with symmetrically arranged nearest-neighbours; the system attains a new rigidity as the material undergoes a phase transition to a solid.
But if you cool the melt down very quickly, the atoms don't have the opportunity to reach these equilibrium positions. The material still solidifies, but retains
