Zn含量对Al-Mg-Si系合金组织与晶间腐蚀性能的影响

Effects of Zn Content on Microstructure and Intergranular Corrosion of Al-Mg-Si Alloy

摘要: 采用扫描电子显微镜（SEM）、透射电子显微镜（TEM）、维氏硬度计和电化学试验等分析技术研究了0.2wt% Zn的添加对于Al-Mg-Si系合金组织、时效硬化、晶间腐蚀(IGC)性能的影响。结果表明，0.2wt% Zn含量的合金峰值硬度为125.8 HV，相较于0.05wt% Zn含量合金的硬度增加了12.7 HV。0.2wt% Zn的加入，使得合金的PFZ变宽，晶界析出相尺寸也略有增加，这导致了Al-Mg-Si系合金的抗晶间腐蚀能力的降低，0.2wt% Zn含量的合金在峰时效状态下的腐蚀电流密度高于0.05wt% Zn含量合金的腐蚀电流密度。

Abstract: The effects of 0.2wt% Zn addition on microstructure, age hardening and IGC properties of Al-Mg-Si alloy were investigated by scanning electron microscope（SEM）, transmission electron microscope（TEM） hardness testing and electrochemistry testing. The results show that the peak hardness of the alloy with 0.2wt% Zn content is 125.8 HV. Compared with 0.05wt% Zn content alloy, the hardness increases by 12.7 HV. With the addition of 0.2wt% Zn, the PFZ of the alloy becomes wider and the grain boundary precipitation phase size increases slightly, which result in the decrease of the intergranular corrosion resistance of Al-Mg-Si alloys. The corrosion current density of the alloy with 0.2wt% Zn content in the peak aging state is higher than that of the alloy with 0.05wt% Zn content.