Influence of I-phase and W-phase on microstructure and mechanical properties of Mg-8Li-3Zn alloy
(1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China;
3. Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo ON N2L 3G1, Canada)
2. National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044, China;
3. Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo ON N2L 3G1, Canada)
Abstract: Microstructures and mechanical properties of LZ83-xY alloys containing I-phase and W-phase were investigated by XRD, OM, SEM and EDS. The experimental results show that the content of I-phase and W-phase changes by varying Zn/Y mass ratio in the LZ83-xY alloys. The cohesion of I-phase/α-Mg eutectic pockets can enhance the strength in the as-cast LZ83-0.5Y and LZ83-1.0Y alloys, while the W-phase has no obvious strengthening effect on the LZ83-1.5Y alloy. In the extruded alloys, the I-phase and W-phase were extruded into the particles with nanoscale size in the β-Li matrix phase. The dispersion strengthening of W-phase was more obvious because of the higher volume fraction. The ultimate tensile strength of extruded LZ83-1.5Y alloy is up to 238 MPa while the elongation is up to 20%.
Key words: Mg-8Li-3Zn alloy; I-phase; W-phase; mechanical properties; as-cast microstructure