Temperature-dependent damping mechanism in ferroelastic-reinforced composites

Phase field modeling and computer simulations were conducted to uncover the fundamental mechanism behind the peak in damping capacity observed in BaTiO₃-reinforced composites, considering both insulating and conductive cases. The damping capacity curve obtained from these simulations, which varies with temperature, reveals dual peaks near T_c for both cases. The first peak, labeled Peak I, occurs below T_c and is attributed to temperature-induced domain reorientation. The second peak, labeled Peak II, occurs above T_c and arises from stress-induced phase transitions between paraelastic and ferroelastic states. This transition results in a double-loop strain-stress hysteresis, akin to the polarization-field hysteresis observed in ferroelectric systems at and above T_c. Between Peak I and Peak II, there is a dip in damping capacity just below T_c, caused by the diminished ferroelasticity of BaTiO₃ particles near this critical temperature. In composite materials, the dual peaks merge into a single peak due to the heterogeneous nature of T_c, influenced by various factors that either raise or lower T_c. This convergence aligns with experimental observations.