I think Roman legionary blacksmiths and medieval English and Welsh bowyers have solved this issue during their respective times as well.
The Romans NEEDED a thrown spear to break, bend, or get stuck when they faced off against the ferocious Gauls and Germanic hordes infamous for human wave attacks against their shield walls. That way, the enemy could not throw the spears back at them, and they designed their pilums to function exactly this way. So advanced was the metallurgy and physics behind the pilum that after the western half of the empire fell, the technology was never replicated by anyone else, not even the eastern empire which continued to function...