Damping behavior and mechanical properties of Mg-Cu-Mn alloy processed by equal channel angular pressing

Equal channel angular pressing(ECAP) was conducted at 250 °C for 4 passes to the as-extruded Mg-3%Cu-1%Mn alloy with high strength and high damping capacity. After ECAP processing, the grain of as-extruded alloy is significantly refined to about 4 μm, both yield strength and tensile strength of the as-extruded Mg-Cu-Mn alloy are decreased, but the ductility is improved. After the ECAP processing, the damping capacity of Mg-Cu-Mn alloy is decreased at room temperature, while is substantially increased at elevated temperatures. After annealing at 300 °C for 1 h, both yield strength and tensile strength of the ECAPed alloy are further decreased, but the ductility is significantly improved. The damping capacity of the as-annealed alloy is increased at room temperature, while is decreased at elevated temperatures. The mechanisms for damping capacity of the alloy at ambient and elevated temperatures were discussed.