(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 利用金相显微镜、X射线衍射、EBSD等检测方法分析铸态、均匀化退火态和挤压态Mg-Hg-Ga合金的显微组织，并采用析氢浸泡法、动电位极化扫描、恒电流放电、交流阻抗法、阳极效率测试，研究均匀化退火及挤压对Mg-Hg-Ga阳极材料腐蚀电化学性能的影响。结果表明：均匀化退火使铸态组织中第二相数量明显减少，挤压后合金发生动态再结晶，晶粒明显细化，并形成{0001}基面织构。均匀化退火提高合金的耐腐蚀性能和阳极电流效率，降低合金的电化学活性。热挤压降低合金的耐腐蚀性能，提高合金的电化学活性和阳极电流效率。挤压态合金表现出最负的平均放电电位-1.841 V(vs SCE)，最大的析氢速率4.13 mL/(cm2·h)和腐蚀电流密度1.010 mA/cm2。均匀化退火态合金的析氢速率和腐蚀电流密度下降到最小，分别为1.75 mL/(cm2·h)和0.241 mA/cm2，阳极电流效率由铸态的53.68%上升到挤压态的66.63%。
关键字: Mg-Hg-Ga合金；挤压；均匀化退火；显微组织；电化学性能
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The microstructures of Mg-Hg-Ga alloy modified by homogenizing and hot extrusion were investigated by optical microscope, XRD and EBSD. The influence of homogenizing and hot extrusion on the corrosion behavior of Mg-Hg-Ga alloy was examined by hydrogen generation tests, potentiodynamic polarization, galvanostatic tests, impedance spectra (EIS) tests and current efficiency tests. The results show that the amount of second phase Mg2Hg significantly reduces after homogenizing. The hot extrusion promotes the dynamic recrystallization and refines the grains of Mg-Hg-Ga alloy, and the {0001} basal texture forms in the hot extruded alloy. The homogenizing promotes the corrosion resistance and anode efficiency of alloy and reduces the electrochemical activity of alloy. The hot extrusion improves the electrochemical activity, anode efficiency and reduces the corrosion resistance at the same time. The extruded alloy performs the most negative mean potential of -1.841 V(vs SCE), the largest hydrogen generation rate corrosion current density are 4.13 mL/(cm2·h) and 1.010 mA/cm2, respectively. The hydrogen generation rate and the corrosion current of the homogenized alloy are the smallest, which are 1.75 mL/(m2？h-1) and 0.241 mA/cm2, respectively. The anode efficiency increases from 53.68% of as-cast alloy to 66.63% of extrusion alloy.
Key words: Mg-Hg-Ga; extrusion; homogenizing; microstructure; electrochemical property
