中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 33 No. 5 May 2023 |
（1. School of Energy and Power Engineering, Changsha University of Science & Technology, Changsha 410114, China;
2. Key Laboratory of Energy Efficiency and Clean Utilization, the Education Department of Hunan Province, Changsha University of Science & Technology, Changsha 410114, China;
3. School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China;
4. Institute of Rare Earth Light Alloys, Hunan Rare Earth Metal Material Research Institute, Changsha 410126, China）
Abstract:The microstructures and corrosion behavior of the as-cast AZ91-xVN (x=0, 0.25, 0.5 and 1 in wt.%) alloys were investigated using optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The results showed that VN can significantly refine and modify the microstructures of AZ91-xVN alloys. The corrosion resistance of the AZ91 alloy was first improved and then deteriorated with the addition of VN particles. The superior corrosion resistance of the as-cast AZ91-0.25VN alloy with the lowest corrosion rate (PW=(1.47±0.06) mm/a) was attributed to the additional grain boundaries. With the further increase of VN content, the amount of the lamellar β-Mg17Al12 precipitation phase increased, and thus the galvanic corrosion between β phase and the α-Mg matrix was promoted, resulting in the deteriorated corrosion resistance of the alloys.
Key words: AZ91-xVN alloys; microstructure; grain refinement; corrosion resistance
