Damping properties of Li5La3Ta2O12 particulates reinforced aluminum matrix composites

A novel concept to design metal matrix composites that exhibit high damping capacity as well as good mechanical performance at room temperature was suggested in this paper. The hard ceramic particulates with high damping capacity at room temperature were embedded as additives into metallic matrix to form the composite materials. Based on this model concept, the Li5La3Ta2O12/Al composites were prepared by powder metallurgy method. The damping capacity (internal friction), microhardness, and yield stress of the Li5La3Ta2O12/Al composites increase with increasing Li5La3Ta2O12 concentration in the range of 0–25 wt%. The maximum damping capacity as high as 0.018 was obtained in a Li5La3Ta2O12/Al-75 wt% composite at 325 K and 2 Hz. The yield strength and microhardness of the Li5La3Ta2O12/Al-80 wt% composites are about 40% and 30% higher than those of the pure Al, respectively. More importantly in the purpose of practical application, the damping capacity of Li5La3Ta2O12/Al-75 wt% composites at room temperature is greater than 0.01.