Effects of flux purification on composition, microstructure and mechanical properties of Mg-9Li-3Al-1Zn alloy
(1. National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China;
2. Beijing Institute of Electronic System Engineering, Beijing 100854, China)
2. Beijing Institute of Electronic System Engineering, Beijing 100854, China)
Abstract: The influence of refining flux composition, refining time, refining temperature, and addition amount on the microstructure and mechanical properties of Mg-9Li-3Al-1Zn alloy was investigated with orthogonal experimental design. The flux purification process for Mg-Li alloys was optimized and the most effective ternary flux composition was identified. Results indicate that flux purification significantly mitigates Li loss during smelting by forming a protective surface layer that reduces Li oxidation and evaporation. The optimal flux composition is LiCl？LiF？CaF2 in a 3？1？2 mass ratio, with a flux addition of 3%, refining temperature of 720 °C, and holding time of 10 min. The elongation of alloy improves to 16.2% after refinement, while the enhancement in strength remains marginal.
Key words: Mg-Li alloys; flux purification; refining process; microstructure; mechanical properties