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设计了一种新的低稀土含量的Mg-4Al-0.5RE(0.25 Y+ 0.25Ce)-0.8Ca合金,研究了挤压铸造AE42与Mg-4Al-0.5RE-0.8Ca合金的显微组织及在不同腐蚀环境下的腐蚀行为.结果表明,显微组织最大的不同为AE42中树枝状的Al-RE相变为新合金中针状的Al-RE相,且新合金中形成了Al2Ca相.腐蚀试验显示,温度的升高及NaCl浓度的提高均能加快合金的腐蚀速率.高温下合金的表面膜发生破坏,未出现钝化现象,而在高浓度的NaCl溶液中表现出钝化现象.新合金具有较好的耐蚀性,主要原因是析出相与α-Mg基体较低的电位差及均匀致密的腐蚀膜.“,”A new low-rare-earth Mg-4Al-0.5RE (0.25Y + 0.25Ce)-0.8Ca alloy was designed.The microstructures of squeeze-cast AE42 and Mg-4Al-0.5RE-0.8Ca alloys were investigated,and the effects of different corrosion environment on the corrosion behavior of Mg-4Al-0.5RE-0.8Ca alloy were analyzed.The results reveal that dendritic Al-RE in the AE42 is converted into acicular Al-RE in the Mg-4Al-0.5 RE-0.8Ca alloy,and the new Al2Ca phase can be generated due to the Ca addition.Corrosion tests reveal that the corrosion rate is increased with the increase in temperature and chloride ion concentration.The surface film is destroyed at high temperature and passivated phenomenon is absent,while the alloy at high NaCl concentration presents the passivated phenomenon.The new alloy exhibits good corrosion resistance,which is attributed to the lower potential difference between precipitation and α-Mg matrix as well as homogeneous dense corrosion film.