AZ61镁合金挤压前预处理工艺研究
Research on Pretreatment Process for AZ61 Magnesium Alloy Before Extruding
彭 建1,2， 佘 欢1， 陈先华1， 潘复生1,2
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作者单位：（1. 重庆大学 材料科学与工程学院，重庆 400044；2. 重庆市科学技术研究院，重庆 401123）
中文关键字： AZ61镁合金； 均匀化退火； 挤压墩粗； 枝晶偏析； 力学性能
英文关键字：AZ61 magnesium alloy; homogenized annealing; upsetting; dendrite segregation; mechanical properties
中文摘要：对AZ61铸锭挤压前的两种均匀化预处理工艺进行对比研究：即390 ℃保温4 h的均匀化退火工艺和
390 ℃保温4 h挤压墩粗。通过光学显微镜观察和室温拉伸试验，比较两种不同的预处理方式对AZ61合金组织和力学性能的影响。结果表明：390 ℃保温4 h高温墩粗与390 ℃保温4 h均匀退火相比，没有明显提高AZ61合金铸态组织枝晶偏析消除程度；两种不同预处理后的合金经挤压后，显微组织差异不大，均由细小等轴的再结晶晶粒和大量的破裂第二相组成。经390 ℃保温4 h均匀退火后挤压的AZ61合金，室温抗拉强度、屈服强度和伸长率分别为329 MPa、244 MPa和12.1%；经390 ℃保温4 h墩粗后挤压的合金的室温拉伸抗拉强度、屈服强度和伸长率分别提高为340 MPa、268 MPa和14.5%。
英文摘要：AZ61 ingots were respectively extruded after homogenized annealing and upsetting at 390 ℃ for 4 h. The microstructures and mechanical properties were compared under the two different pretreatment methods by observing microstructures with optical microscope and testing tensile properties at room temperature. The results show that， compared with 390℃×4 h homogenized annealing, there is no significant improvement under 390 ℃× 4 h upsetting to eliminate the dendrite segregation in as-cast AZ61 alloys. The differences are not apparent in the microstructures of the extruded AZ61 alloys with two different pretreatment methods, both in which, the small equiaxed recrystallized grains occur and a large number of broken second-phase are distributed. While, the tensile strength, yield strength and elongation of AZ61 alloy with upsetting are respectively increased to 340 MPa, 268 MPa and 14.5%, compared with that of AZ61 alloy with homogenized annealing at 390 ℃ for 4 h, they are 329 MPa, 244 MPa and 12.1%, respectively.