Intergranular Corrosion Dynamics of Different Oriented 7050 Aluminum Alloy

For 7050aluminum alloy,the intergranular corrosion is apt to occur during use,and there are differences in the corrosion phenomena with varing its sampling directions.In this paper,the tissue distribution and the intergranular corrosion performance of different orientation 7050aluminum alloy samples with the thickness of 60mm were investigated using the optical microscope and the scanning electron microscope.Results show that the grains along the sheet rolling direction are flat and present the second phase chain distribution around the grain boundaries,and the intergranular corrosion starts from the second phase of the grain boundaries.The grain boundaries of the L-T side after corrosion are easy to exfoliate,and the maximum intergranular corrosion depth is the minimum,belonging to the third level intergranular corrosion.For the T-S and L-S sides,since there are more grain boundaries after corrosion,the corrosion reaction is prone to develop towards the depth direction,and the intergranular corrosion depth of the T-S side is the maximum,belonging to the fourth level intergranular corrosion.The corrosion weight loss of the T-S side sample is maximum, which indicates that there are more corrosion products exfoliated.For different orientation sampling specimens,the laws of the corrosion weight loss and the maximum corrosion depth varying with the time are obtained,and the intergranular corrosion kinetics equations are presented after fitting.