Bimodal grain sized 7075 alloys were prepared to test corrosion resistance.
Effects of coarse and fine grains content in alloy matrix on IGC were estimated.
IGC susceptibility of alloys decreased with increasing ratio of fine grains.
IGC preferentially propagate along grain/sub-grain boundaries in coarse grains.
GBP in coarse grains are bigger and more continuous, and contain more Fe and Cu.