As an aside, iron also is strengthened by hammering on it. It’s called forging. Been done for hundreds of years.
Forging makes it more fragile, but stronger- when heated, it becomes easier to bend (less strong, or more maleable), but when hammered, it will become more solid, less malleable, but also more apt to break, or snap, instead of bending when stressed.
I used to work with gold, and would pour out melted gold, which was very bendy, and would work it through a roller of,vsriousmsizes and shapes, and after awhile, it became harder to squash to size, and eventually would crack if overworked.