均匀化退火及挤压对Mg-Hg-Ga合金显微组织和耐腐蚀性能的影响

发布时间：2018-04-02 00:21

本文选题：Mg-Hg-Ga合金　切入点：挤压　出处：《中国有色金属学报》2017年01期

【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/(cm~2·h)和腐蚀电流密度1.010mA/cm~2。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/(cm~2·h)和0.241 mA/cm~2,阳极电流效率由铸态的53.68%上升到挤压态的66.63%。
[Abstract]:The microstructure of as-cast, homogenized annealed and extruded Mg-Hg-Ga alloys was analyzed by X-ray diffraction (EBSD) with metallographic microscope. The microstructures of as-cast, homogenized annealed and extruded Mg-Hg-Ga alloys were analyzed by means of hydrogen evolution immersion, potentiodynamic polarization scanning, constant current discharge, AC impedance method, etc.The effect of homogenization annealing and extrusion on the corrosion electrochemical properties of Mg-Hg-Ga anode materials was studied.The results show that the number of the second phase in the as-cast microstructure is obviously reduced after homogenization annealing, the dynamic recrystallization of the alloy occurs after extrusion, the grain size is obviously refined, and the {0001} basal texture is formed.Homogenization annealing improves the corrosion resistance and anode current efficiency of the alloy, and reduces the electrochemical activity of the alloy.Hot extrusion reduces the corrosion resistance of the alloy and improves its electrochemical activity and anode current efficiency.The extruded alloy exhibits the most negative average discharge potential of -1.841 V(vs, the maximum hydrogen evolution rate of 4.13 mL/(cm~2 / h) and the corrosion current density of 1.010 Ma / cm ~ (-2).The hydrogen evolution rate and corrosion current density of homogenized annealed alloy decreased to a minimum of 1.75 mL/(cm~2 路h) and 0.241 Ma / cm ~ (-2), respectively. The anodic current efficiency increased from 53.68% in as-cast state to 66.63% in extruded state.
【作者单位】：中南大学材料科学与工程学院;
【基金】：国家自然科学基金资助项目(51171101)~~
【分类号】：TG146.22;TG166.4;TG379

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