( 上海交通大学 材料科学与工程学院， 上海 200030)
摘 要: 研究了Ca对AZ91D镁合金显微组织、力学性能和腐蚀性能的影响。 当AZ91D中加入的Ca含量大于1.0%时， β相(Mg17Al12)减少，并且在晶界上形成了网状分布的Al2Ca相。 拉伸测试表明， 当加入Ca含量小于1%时， 可以提高合金的常温抗拉强度和延伸率， 继续增大Ca含量时合金的力学性能明显下降。 当AZ91D中加入的Ca含量达到1.0%时， 常温抗拉强度和延伸率较AZ91D分别提高了8.2%和29.3%，并且腐蚀速率下降为AZ91D的17.2%。 其原因主要是由于形成了网状分布的Al2Ca相， 使镁合金的自腐蚀电位升高， 腐蚀电流密度降低， 从而阻碍了镁合金的腐蚀。
关键字: 镁合金； 钙； 显微组织； 力学性能； 腐蚀； 极化曲线
（ School of Materials Science and Engineering,
Shanghai Jiaotong University, Shanghai 200030, China）
Abstract: The effect of calcium on microstructure, mechanical properties and corrosion resistance of magnesium alloy was studied. When the addition of Ca is more than 1%, the β phase decreases and some reticular Al2Ca phases form on grain boundaries. The tensile tests indicate that when the Ca addition is less than 1%, the ultimate strength and elongation of AZ91D alloy increase, but when the Ca addition is more than 1%, the strength and elongation of AZ91D alloy decrease. The ultimate strength and elongation of AZ91D alloy with the addition of 1% Ca respectively increase by 8.2% and 29.3%, and the corrosion rate decreases to 17.2%. This is mainly caused by the formation of reticular Al2Ca phase, which acts as an effective barrier against corrosion and makes the corrosion potential increasing and the corrosion current density decreasing.
Key words: magnesium alloy; calcium; microstructure; mechanical properties; corrosion; polarization curves
