What happens to the crystal structure of metals when it is melted?
When anything melts, the crystal structure is destroyed.
The crystal structure is a regular repeating lattice, which can only occur in the solid state. Liquids have no regular structure, so they are not crystalline.
When liquids freeze again, a few things can happen, depending on the conditions in which they freeze. They can reform their original structure, they can form a different structure, or they can freeze in amorphous form (no crystalline structure).
