Effect Of Organizational Structure On Corrosion Resistance Of Aluminum Alloy

With the continuous development of technology and innovation, it shows higher requirements on the performance of aluminum, and corrosion of aluminum is a problem all the times. How to improve corrosion mechanism for aluminum-depth and research on corrosion protection measures all are current problems to be solved.Selected alloy is cast aluminum alloy A356, in this project, composite micro-alloying and T6 heat treatment are used to improve its organizational structure, electron backscatter diffraction (EBSD) experiment is conducted on the grain size, grain boundary type, grain boundaries characteristics. Electrochemical experiments is conducted to study the corrosion resistance, to explore the mechanism of grain boundaries which affect the corrosion resistance of aluminum alloy. The results show: With the change in the ratio of elements, grain size, grain boundary of special grain boundaries, as well as the proportion of misorientation angle grain boundaries have undergone significant changes. When the element ratio reached 0.15% La,0.3% Y, the most obvious grain refinement is found, the highest E3 proportion of grain boundaries is shown, the proportion of large-angle grain boundaries is significantly improved and corrosion resistance improved significantly as well.A356 aluminum alloy is put in the solution:KMnO4 solution 35g/L+K2HPO3 solution 130g/L of phosphoric acid; the speed is adjust to 500r/min, the temperature of the solution is 45 ?, the pH value was adjusted to 4, the conversion time is set in 20min; in the phosphate film on the basis of a mixed solution of sulfuric acid, copper, consisting of alcohol, keeping the temperature on 40?,40min after electrode position prepared super hydrophobic coatings. The surface morphology and cross section of the film morphology were observed and the corrosion was tested, and the NMT technology was used to detect the velocity and concentration of Cl" film surface from corrosion resistance outflow stream within the test sample ions. It was found that the ion outflow, the corrosion resistance of the alloy surface was enhanced.Aluminum alloy samples (Al-Si-Mg) of different proportions of Al were prepared. By the samples Mg2Si phase morphology observation and spectrum scans, the ratio of the sample and the actual element contents were detected. We found that the morphology of Mg2Si phase, the number and distribution of Mg2Si phase improved corrosion resistance.