Simultaneously improved mechanical properties and corrosion resistance of Mg-10.02Li-5.69Al-0.08Er alloy by solutionizing treatments

This study explores the impact of varying solutionizing treatment temperatures on the mechanical properties and corrosion resistance of Mg-10.02Li-5.69Al-0.08Er (LA106) alloy. Results revealed that the alloy treated at 400 °C exhibits a good combination of comprehensive mechanical properties and corrosion resistance. After solutionizing treatment at 400 ℃, solution strengthening and the rod-like α phase shrinks along the width direction and transforms into a needle-like structure, which helps to hinder the dislocation movement and consequently enhancing the strength of the alloy. Additionally, the fine particles and needle-like α phase coordinate deformation with the β phase matrix, maintaining acceptable ductility. The alloy treated at 400 °C demonstrates superior corrosion resistance, primarily attributed to the needle-like α phase effectively impeding corrosion propagation. Furthermore, fine particles with relatively negative Volta potential, distributed within the α phase and β phase, effectively mitigate microgalvanic corrosion between the α phase and β phase. Nevertheless, it is noteworthy that the corrosion resistance of the LA106 alloy at 250 ℃ and 300 ℃ is lower than that observed at 400 ℃. This can be ascribed to the abundance of precipitates distribute along the grain boundaries, leading to galvanic corrosion and subsequently reducing the corrosion resistance. •The mechanical and corrosion resistance properties of the Mg-10Li-6Al alloy enhanced after the heat treatment.•Heat treatment can improve the mechanical properties due to the α phase with a slender acicular structure.•Heat treatment can enhance the corrosion resistance due to the second phase particles within the grain.