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.