Corrosion research and fractal characteristics of as-cast and semi-solid AZ91D magnesium alloys

As-cast and semi-solid AZ91D magnesium alloys samples were corroded in distilled water, 0.9% NaCl solution and 3.5% NaCl solution for various time, respectively. With the increase of corrosion time and the concentration of corrosion solution, the corrosion degree of the alloys gradually deepened. The corrosion resistance of semi-solid alloy with nearly spherical grain refinement was significantly reduced, resulting in more corrosion pits and higher corrosion rate. According to the fractal analysis, the corrosion process of semi-solid alloy was more uniform under the same conditions. The fractal theory accurately described the corrosion process, further providing a better grasp of the corrosion behavior of AZ91D magnesium alloy.