Microstructural homogeneity, texture and corrosion properties of RE-doped 55Mg-35Pb-9.2Al-0.8B alloy fabricated via equal channel angular pressing (ECAP)

Abstract

A fine-grained 55Mg-35Pb-9.2Al-0.8B alloy was fabricated through equal channel angular pressing (ECAP) with the addition of rare earth (RE). The corrosion behavior of the alloy was investigated by electrochemical test, hydrogen evolution test and salt spray test. The results demonstrate the corrosion resistance ranking of the as-cast specimens with RE elements as follows: 0.5Sc > 0.5Y > 0.5Sm > 0.5Ce > 0.5Nd > as-cast. After the 1st ECAP process, the corrosion resistance of the alloy samples follows this order: 0.5Sc > 0.5Ce > 0.5Y > 0.5Sm > 0.5Nd > as-cast. The addition of 0.5Sc has the most significant effect on the improvement of corrosion resistance of the alloy. At the same time, the corrosion resistance of 0.5Ce alloy was improved after ECAP. The microstructure of 55Mg-35Pb-9.2Al-0.8B alloy was refined and the dispersion of the second phase was reduced by adding RE elements and ECAP. Grain refinement can stabilize the corrosion product layer and improve corrosion resistance. This study lays the foundation for comprehending and future applications of the ECAP process in fabricating high-performance Mg-Pb-Al-B-RE alloys.