用失重法、金相显微镜和扫描电镜（SEM）研究了金属型铸造镁合金AZ91D和触变成型镁合金AZ91D在3.5% NaCl水溶液中的腐蚀行为与组织之间的关系。结果显示：触变成型镁合金的耐蚀性高于金属型铸造镁合金是因为微观组织的不同所致。在腐蚀初期，触变成型镁合金内层试样腐蚀速率高于表层试样，这是由于表层组织中的β相含量高于内层组织；随腐蚀进行，腐蚀速率基本一致.腐蚀主要发生在阳极（共晶α相和α相）区域，β相作为电偶腐蚀的阴极。电偶对的腐蚀电位、相对位置和面积比是影响触变成型镁合金腐蚀速率的主要因素。
The relationship between corrosion behaviors and microstructure of thixoformed （TH）AZ91D alloys and permanent mould cast （PMC） AZ91D alloys in 3.5% NaCl aqueous solution was studied by optical microscope，SEM and weight loss method. The result showed that the corrosion resistance of the TH alloy was higher than that of the PMC alloy because their microstructures were significantly different. For the TH alloy， due to the volume fraction of β phase in the substrate was lower than surface layer，the corrosion rate of the former was higher than the latter during the initial stage of corrosion test，but this difference decreased as the corrosion proceeded.The corrosion mainly occurred in the primary α particles and secondary α phase because these two structures were taken as the cathode and β phase as the cathode in galvanic corrosion.The Ecorr between the galvanic couples，the relative distribution of the α and β phases and the area ratio of the α phase to β phase exposured on the speci?鄄men surface were the main factors to determine the corrosion rate.
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