Effect of extrusion parameters on microstructure, mechanical properties and damping capacities of Mg-Y-Zn-Zr alloy

In this work, different extrusion processes were carried out on a Mg-3.16Y-1.85Zn-0.37Zr (wt%) alloy containing long period stacking ordered (LPSO) phases. The effect of extrusion parameters on the micro-structure, mechanical properties and damping capacities of the alloy were investigated. The results show that the alloy extruded at 360 degrees C and a ratio of 9:1 shows good comprehensive properties with a tensile yield strength (TYS) of 280 MPa, ultimate tensile strength (UTS) of 330 MPa, elongation (EL) to failure of 21% and damping value Q-1 of 0.023 (strain amplitude epsilon = 10-3) at room temperature (RT). As the extrusion temperature or ratio increases, the strength decreases and EL increases, while the damping value of epsilon = 10-3 at RT is slightly down due to the decrease in the LPSO phase and dislocation density. All as-extruded alloys show a similar variation tendency for the relationship between Q-1 and test temperature T, with elevated temperature (ET) damping capacities Q-1 > 0.01 at a frequency of 1 Hz and T > 300 degrees C. Strengthening mechanisms for mechanical properties of the as-extruded alloys have also been analyzed, and the damping capacities are also discussed in terms of the Granato-Lucke (G-L) dislocation theory and grain boundary sliding. The results of the present work provide a new perspective for further developing high-performance Mg-Y-based alloys with both high damping and excellent comprehensive mechanical properties by careful tailoring of the extrusion process parameters. (c) 2022 Elsevier B.V. All rights reserved.