Effects of Annealing Treatment on Mechanical and Damping Properties of ZK60 Magnesium Alloy Sheets

Effects of annealing treatment on microstructure, mechanical and damping properties of as-rolled ZK60 magnesium alloy sheets were examined and analyzed. The as-rolled alloy annealed at 340 °C for 1 h undergoes static recrystallization and exhibits the best combination of mechanical properties, with UTS of 333 MPa, YS of 268 MPa and El of 19%. With the strain amplitude below 4 × 10–4, the damping mechanism of the as-studied alloys can be explained by the Granato–Lüker (G–L) theory. With the strain amplitude higher than 4 × 10–4, the occurrence of micro-yield phenomenon and dislocation multiplication make the damping behavior of the alloy no longer explainable by G–L theory. The growth in damping becomes faster for all the alloys when the strain amplitude exceeds 4 × 10–4, and the alloy annealed at 340 °C for 1 h exhibits the highest damping capacity with the strain amplitude higher than 5 × 10–4 as a result of the activation of more non-basal slip systems, which will consume more elastic vibration energy and thus improve the damping capacity of the alloy. This provides a theoretical basis for the development of high-strength and high-damping magnesium alloys.