(中南大學 材料科學與工程學院，長沙 410083)
摘 要: 利用金相顯微鏡、X射線衍射、EBSD等檢測方法分析鑄態(tài)、均勻化退火態(tài)和擠壓態(tài)Mg-Hg-Ga合金的顯微組織，并采用析氫浸泡法、動電位極化掃描、恒電流放電、交流阻抗法、陽極效率測試，研究均勻化退火及擠壓對Mg-Hg-Ga陽極材料腐蝕電化學性能的影響。結果表明：均勻化退火使鑄態(tài)組織中第二相數(shù)量明顯減少，擠壓后合金發(fā)生動態(tài)再結晶，晶粒明顯細化，并形成{0001}基面織構。均勻化退火提高合金的耐腐蝕性能和陽極電流效率，降低合金的電化學活性。熱擠壓降低合金的耐腐蝕性能，提高合金的電化學活性和陽極電流效率。擠壓態(tài)合金表現(xiàn)出最負的平均放電電位-1.841 V(vs SCE)，最大的析氫速率4.13 mL/(cm2·h)和腐蝕電流密度1.010 mA/cm2。均勻化退火態(tài)合金的析氫速率和腐蝕電流密度下降到最小，分別為1.75 mL/(cm2·h)和0.241 mA/cm2，陽極電流效率由鑄態(tài)的53.68%上升到擠壓態(tài)的66.63%。
關鍵字: Mg-Hg-Ga合金；擠壓；均勻化退火；顯微組織；電化學性能
（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
