Not a metallurgist but — my understanding is that pure iron weapons are quite inferior to bronze. Pure iron is very soft and ductile. It would not hold an edge well and is easily bent - to the point that some sources say they would need to be repeatedly un-bent during battle.

Another advantage of bronze weapons is they could be cast in a mold instead of forged.

Iron was much more plentiful than copper and tin however (especially as they were mined out), which was the main reason bronze fell out of use.

Good steel was superior to both, but much harder to make.