Micro-mechanism of Galvanic Corrosion Behavior and Its Effects on Materials' Performance

In order to study the effects of the stress and galvanic factors on the corrosion behavior of 2A12 alloy and 45 steel, a special loading device were applied to investigate the galvanic corrosion between 2A12 alloy and 45 steel under applied tensile stress in neutral 3.5% NaCl solution. The morphology changes on the surface of 2A12 alloy was investigated based on electron microscopy (SEM) and X-ray diffraction (XRD), and the effects of galvanic corrosion on the mechanical properties of 2A12 alloy were investigated using the methods of tensile test. The results show that the morphology of corrosion possess characteristics of uniform pitting corrosion macroscopically however that of localize corrosion microscopically without the effects of external stresses. The pitting corrosion develops into larger dimension and the localized corrosion penetrated into the matrix with the external stress increased. The microcosmic structure and corrosion morphology of 2A12 alloy are changed from the external stress, which may evidently accelerate the galvanic corrosion of anode materials 2A12, especially localized corrosion expanded from the surface into the entrails. Based on the characteristics of corrosion metrics and the weight loss ratio of 2A12 in different external stresses and corrosion time, the forecasting model was established to predict the performance and life.