( 上海交通大學(xué) 材料科學(xué)與工程學(xué)院， 上海 200030)
摘 要: 研究了Ca對(duì)AZ91D鎂合金顯微組織、力學(xué)性能和腐蝕性能的影響。 當(dāng)AZ91D中加入的Ca含量大于1.0%時(shí)， β相(Mg17Al12)減少，并且在晶界上形成了網(wǎng)狀分布的Al2Ca相。 拉伸測(cè)試表明， 當(dāng)加入Ca含量小于1%時(shí)， 可以提高合金的常溫抗拉強(qiáng)度和延伸率， 繼續(xù)增大Ca含量時(shí)合金的力學(xué)性能明顯下降。 當(dāng)AZ91D中加入的Ca含量達(dá)到1.0%時(shí)， 常溫抗拉強(qiáng)度和延伸率較AZ91D分別提高了8.2%和29.3%，并且腐蝕速率下降為AZ91D的17.2%。 其原因主要是由于形成了網(wǎng)狀分布的Al2Ca相， 使鎂合金的自腐蝕電位升高， 腐蝕電流密度降低， 從而阻礙了鎂合金的腐蝕。
關(guān)鍵字: 鎂合金； 鈣； 顯微組織； 力學(xué)性能； 腐蝕； 極化曲線
（ 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
