The enhance of Al-TCB seed alloy on the corrosion resistance of 7050 alloy by multi-level structures modification

Corrosion resistance is among the key elements determining the service life of alloys. The impact of as-cast grain refinement by Al-TCB seed alloy on the corrosion resistance of 7050 alloy under final state was studied. Thus, systematic analyses of immersion and electrochemical corrosion tests proves the pitting and intergranular corrosion resistance of 7050-T alloy are improved by 0.5 % Al-TCB addition compared with 7050 alloy, while the degree of exfoliation corrosion has little change in the strong corrosion environment. The enhancement of pitting and intergranular corrosion resistance is largely due to the modification of multi-level structures of 7050-T alloy by adding Al-TCB seed alloy. Such structures mainly include more discontinuous distributed micron-scale Al 7 Cu 2 Fe phase with smaller size, more fine and dispersed aging precipitates inside grains, less numerous and more discontinuous precipitates with reduced size at grain boundaries, smaller grain size and uniform GND, etc.