(上海交通大学 国家轻合金精密成型工程中心， 上海 200030)
摘 要: 研究了不同稀土铈含量对AZ61合金显微组织和力学性能的影响。 实验发现： 加入稀土铈后， AZ61合金铸态组织的β相变少、 变细， 铸态晶粒细化； 大部分铈与铝结合生成高熔点、 高热稳定性的稀土相Al4Ce； 在热挤压和退火过程中， Al4Ce能够阻碍晶粒或亚晶粒的长大, 使晶粒细化。 适量的稀土铈提高了挤压态合金的强度、 延伸率和显微硬度； 而过量的稀土铈则会导致AZ61合金的性能下降； 含1.0％稀土铈的挤压态合金可得到最高的抗拉强度308.1MPa、 最高屈服强度180.1MPa、 最大的显微硬度HV80.5和最高的延伸率14.2％； 所有试验合金的断裂方式是解理断裂。
关键字: AZ61+Ce； 挤压； 显微组织； 力学性能
of AZ61 wrought magnesium
（National Engineering Research Center of Light Alloys Net Forming,School of Materials Science and Engineering, Shanghai Jiaotong University, Shanghai 200030, China）
Abstract: Effects of Ce addition on the microstructures and mechanical properties of the AZ61 alloy have been investigated. It is found that Ce makes refinement of Mg17Al12 and grains, and decreases the amount of Mg17Al12 phase. Most of Ce reacts with aluminum to form compounds of Al4Ce with high melting point and elevated temperature stability which retards grain growth during hot deformation. Certain amount of Ce increases tensile strength, yield strength, elongation and hardness. With more addition, Ce would combine more Al in matrix and decrease strengthening effect because Al4Ce phase would become coarsening. The mechanical tests indicate that AZ61 has the best properties when the content of Ce is 1.0％. Maximum tensile strength, maximum yield strength and maximum elongation are 308.1MPa, 180.1MPa and 16.2％, respectively. The fracture mechanism of AZ61+Ce alloys is cleavage.
Key words: AZ61+Ce; extrusion; microstructures; mechanical properties
