Investigation on Damping Capacities of Spherical Mg₂Si Magnesium Matrix Composites Prepared by Super-Gravity Method

¹ Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 810008 Xining, China
² Qinghai Engineering and Technology Research Center of Comprehensive Utilization of Salt Lake Resources  
³ University of Chinese Academy of Sciences, 100049 Beijing, China
⁴ Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, 100190 Beijing, China

^* Corresponding author: douglass@ipe.ac.cn (D. P. Duan), yangxm71@ipe.ac.cn (X. M. Yang)

Abstract

Due to inherent high damping capacities of Mg, Mg-based alloys or composites can absorb enormous elastic energy, thus, can be used as damping materials playing important role in reducing vibration and noise. Spherical Mg₂Si magnesium matrix composites were prepared by super-gravity method with fly ash floating beads with particle sizes of 80, 125 and 500 μm. The microstructures and damping capacities of prepared samples were discussed. Spherical and fragment-shaped Mg₂Si phases were observed in the matrix by SEM micrograph. Increasing particle size of fly ash floating beads can lead to an obviously decreasing tendency of internal friction tan φ. The critical strain ε_cr=1.9×10⁻² of ε – tan φ curve and critical temperature T_cr=150 °C of T – tan φ curve for tan φ changing from slowly to greatly increasing. Damping peaks occur in the vicinity of strain ε=5.2×10⁻² in ε –tan φ curve whereas no damping peaks occur in T –tan φ curve.