Effect of Zn/Ga Ratio on Damping and Thermal Behaviors of Fine-Grained Mg-Zn-Ga Sheets

The Mg-xZn-yGa (x + y = 1 at.%) alloys are prepared by high strain rate rolling at 300 °C with the rolling strain rate of 9.1 s−1. The effects of the Zn/Ga ratio on microstructure, mechanical, damping and thermal properties of the as-rolled alloys are investigated by x-ray diffraction, tensile testing, dynamic mechanical analyzer and laser-flash method. The as-rolled alloy exhibits the dynamic recrystallization (DRX) volume fraction above 90%. The DRX volume fraction and the grain size increase with the lower Zn/Ga ratio. With the lower Zn/Ga ratio, the elongation and the damping capacity increase gradually. The Mg-1at.%Ga alloy exhibits the highest elongation (31.1%) and the biggest damping capacity, with Q−1 of 0.019 at the strain amplitude of 0.1%. However, the room temperature thermal conductivity decreases with the lower Zn/Ga ratio, and the Mg-1at.%Zn alloy exhibits the highest value (143 W/(m K)). The Mg-0.75at.%Zn-0.25at.%Ga alloy has the best comprehensive performance.