时效时间对ZA35-1.35Si-0.3Zr合金组织及电化学性能的影响

Effect of aging time on microstructure and electrochemical properties of ZA35-1.35Si-0.3Zr alloy

用金相显微镜、XRD、扫描电镜以及电化学工作站,研究不同时效时间对ZA35-1.35Si-0.3Zr合金组织和电化学性能的影响。结果表明:固溶时效处理可以有效减小ZA35-1.35Si-0.3Zr合金晶粒尺寸,提高其电化学性能;时效时间为6 h时,合金晶粒尺寸最小,第二相数量明显增多且颗粒细小、分布均匀;在6 h时效时间下合金的电化学性能最好,腐蚀电流密度比铸态ZA35-1.35Si-0.3Zr合金降低71.9%;时效处理ZA35-1.35Si-0.3Zr合金在质量分数为3.5%的NaCl溶液中电化学性能增强的主要原因是合金的容抗弧变大,极化电阻增加,腐蚀速率降低。

The effects of different aging time on the microstructure and electrochemical properties of ZA35-1.35 Si-0.3 Zr alloy were investigated by metallographic microscope, XRD, scanning electron microscopy and electrochemical workstation. The experimental results show that the solid solution and aging treatment can reduce the grain size of ZA35-1.35 Si-0.3 Zr alloy and improve its electrochemical performance effectively. When the aging time is 6 h,the grain size of the alloy is the smallest,the number of the second phase is increased obviously,and the particle size is distributed evenly. Further,the electrochemical performance is optimal under the condition of 6 h aging time,and the corrosion current density is 71.9% lower than that of the ascast ZA35-1.35 Si-0.3 Zr alloy. The main reason for the excellent electrochemical performance of ZA35-1.35 Si-0.3 Zr alloy by aging treatment in mass fraction 3.5% NaCl solution is the largest capacitive reactance arc,which leads to an increase in polarization resistance and a decrease in corrosion rate.