(华南理工大学 机械与汽车工程学院 国家金属材料近净成形工程技术研究中心，广州 510640)
摘 要: 采用一种新型剧塑性变形工艺—T型通道挤压(TCP)对ZK60镁合金在673 K下以A和Bc两种路径进行1~4道次挤压变形，通过光学显微镜观察变形镁合金的显微组织，并对TCP变形镁合金的不同部位在应变速率4×10−3 s−1时进行室温拉伸性能测试。结果表明：塑性变形最大的部位是试样中间部位的最底部，其组织特征为细小晶粒包围着大晶粒，大晶粒呈拉长的流线状；4道次变形后，A路径的平均晶粒尺寸由退火态时的88.5 μm细化至2.4 μm，Bc路径的平均晶粒尺寸则细化至4.6 μm，但组织更均匀；同时，在相同道次TCP变形后，A路径变形合金的屈服强度都高于Bc路径变形合金的，但前者的抗拉强度和塑性却低于后者的；此外，试样最底部的抗拉强度和屈服强度均高于试样顶部的，经Bc路径2道次变形后试样底部与顶部的抗拉强度和屈服强度分别相差39.5和43.1 MPa，而经4道次变形后试样两个部位的抗拉强度和屈服强度分别只相差21.2和11.7 MPa。
关键字: 镁合金；T型通道挤压；剧塑性变形；显微组织；力学性能
ZK60 magnesium alloy processed by T-shape channel pressing
（National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials,
School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:ZK60 magnesium alloy was deformed by a new process of severe plastic deformation(SPD)—T-shape channel pressing (TCP) from 1 pass to 4 passes at 673 K using route, A and Bc. The microstructure of TCPed ZK60 was observed by optical microscopy, and the mechanical properties of different TCPed parts were tested with strain rate of 4×10−3 s−1 at room temperature. The results show that the biggest plastic deformation is located at the bottom of sample, and the microstructure character is coarse grains surrounded by fine grains, and the coarse grains are elongated to be streamline. After 4 passes, the average grain size is refined from 88.5 μm of the as-cast alloy to 2.4 μm for the alloy by route A, and to 4.6 μm for alloy by route Bc with more homogeneous microstructure. Meanwhile, at the same pass, the yield strength for alloy by route A is higher than that of the alloy by route Bc, but the tensile strength and ductility of the former alloy are lower than those of the latter. In addition, the tensile strength and yield strength at the bottom are higher than those at the top. The differences of tensile strength and yield strength between the bottom and top of the alloy deformed by route Bc are 39.5 MPa and 43.1 MPa for 2 passes, and only 21.2 MPa and 11.7 MPa for 4 passes, respectively.
Key words: magnesium alloy; T-shape channel pressing; severe plastic deformation; microstructure; mechanical property
