Mg-Hg-Ga合金组织演变及热处理对材料电性能的影响

Microstructure evolution of Mg-Hg-Ga alloy and impact of heat treatment on electric properties

Mg-Hg-Ga合金是一种海水激活动力电池的阳极材料,为提高海水激活电池的各项电性能,采用金相显微组织观测、扫描电子显微镜法（SEM）、X射线衍射光谱法（XRD）、恒阻放电等方法重点研究了Mg-Hg-Ga合金在塑性变形过程中的组织演变过程及热处理对材料组织和电性能的影响。结果表明：塑性加工完全消除了铸态合金中合金元素在晶界的偏聚,使合金元素分布均匀;在200~300℃下退火组织研究发现,在低温下进行退火,合金的组织仍然保持加工状态,在260℃时合金组织发生了完全再结晶,平均晶粒尺寸为20~30μm,在300℃时材料晶粒发生了明显的长大。对不同温度退火材料的电性能研究得出,退火温度对合金的电性能有一定影响;对材料腐蚀机理的初步研究发现,镁合金负极材料的腐蚀实际是合金元素不断溶解、沉积、再溶解、再沉积的循环。

To improve the electric properties of battery, the microstructure evolution of Mg-Hg-Ga alloy during plastic deformation and the impact of heat treatment on the microstructure and electric properties of the alloy were investigated by metallurgical microscopy, SEM, XRD and constant resistance discharge method. The results show that the plastic deformation eliminates the alloy elements segregation of the as-cast Mg-Hg-Ga alloy, and the composition distribution is uniform. The annealing treatment at 200-300 ~C was carried out. The microstructure of alloy remains process state after heat treatment at low temperature. The entire recrystallization is produced at 260℃, and the average grain size is 20-30μm after the heat treatment. The grain size obviously grows at 300℃. The effect study of the temperature on the electrochemical properties of the alloy shows that it has some effect. The results demonstrate that pitting, slot corrosion and general corrosion co-exist in the Mg-Hg-Ga anode material.