Corrosion Research and Fractal Characteristics of As-Cast and Semisolid AZ91D Magnesium Alloys

As-cast and semisolid AZ91D magnesium alloy samples were corroded in distilled water, 0.9% NaCl solution, and 3.5% NaCl solution for various times, 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 semisolid alloy with nearly spherical grain refinement was significantly reduced, resulting in more corrosion pits and a higher corrosion rate. According to the fractal analysis, the corrosion process of semisolid 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.