There is ‘copperweld’ wire which is an iron core for more strength coated with copper for lower resistance than the iron. This is preferred for antennas for its strength. Purer copper wire will break more often, HOWEVER, I had a really pure (Oxygen free), bare copper wire up for about 5-6 years before it broke, and one with thick plastic insulation for 8-10 years, so it is hard to predict.
