Cu clusters evolvement in Fe-1.18%Cu binary alloy

Microstructure evolution of Fe-1.18%Cu binary alloy during solution and aging at 550°C was investigated under a high-resolution electron microscope (HREM). In addition, the aging strengthening mechanism was investigated based on the precipitation strengthening theory. Results show that there were lots of Cu atom clusters in the ferrite matrix during solid solution and initial aging stage, and Cu-rich metastable Fe-Cu particles precipitate subsequently at the aging hardness peak. It is found that there were high-density dislocations and stacking fault substructure in the Cu clusters that forms the obstacle of the dislocation motion, which should be the dominant reason of strengthening in the Fe-Cu alloy.