(1. 东南大学 材料科学与工程学院 江苏省先进金属材料高技术研究重点实验室，南京 211189；
2. 南京工程学院 材料工程学院，南京 211167)
摘 要: 采用交流钨极氩弧焊和热碾压装置对AZ31变形镁合金进行焊接试验和热碾压试验；利用光学显微镜、扫描电镜(SEM)、显微硬度计、电子拉伸试验等手段对焊接接头的显微组织、元素分布、断口形貌、接头硬度和强度等进行分析。结果表明：热碾压熔焊接头的抗拉强度可达225 MPa，为母材金属的90%以上，而焊态下熔焊接头的抗拉强度仅为母材金属的60%左右；热碾压焊接试样的伸长率(9%~11%)均高于焊态试样的(6%~8%)；热碾压接头断口呈现一定的准解理断裂特征，且可以观察到热碾压塑性变形流变线，而焊态断口呈现以解理断裂为主的断裂机制，同时伴随有极少量的韧窝断裂特征。
关键字: AZ31镁合金；热碾压；变形；力学性能
（1. School of Material Science and Engineering, Jiangsu Key Laboratory for Advanced Metallic Materials,
South East University, Nanjing 211189, China;
2. School of Material Engineering, Nanjing Institute of Technology, Nanjing 211167, China）
Abstract:The conventional welded joint and hot rolled tests were carried out for AZ31 magnesium alloy on TIG welding and hot rolling equipment, and the microstructure, the element distribution, the appearance of fracture, hardness and strength of the welded joint were studied by OM, SEM, micro-hardness tester, tensile testing machine. The results show that the tensile strength of the hot rolled welded joint is 225 MPa, which is over 90% of that of the base metal, and the tensile strength of the conventional welded joint is just about 60% of that of the base metal. The elongation of the hot rolled welded specimen (9%−11%) is higher than that of the conventional welded specimen (6%−8%). The hot rolled joint fracture shows some characteristics of the quasi-cleavage fracture, and the plastic deformation flow lines can be observed. The conventional welded joint shows the cleavage fracture mechanism, accompanied by a very small amount of dimple fracture.
Key words: AZ31 magnesium alloy; hot rolled; deformation; mechanical properties
