Analysis of transient mechanical loss due to thermal stresses in metal matrix composites

Mechanical spectroscopy has been used to study the thermal stress relaxation at the interfaces in magnesium matrix composites. The mechanical loss spectra measured as a function of temperature show an intrinsic component superimposed on transient damping. A model of thermal stress relaxation by dislocation motion controlled by a solid friction mechanism, where the transient damping depends non linearly on T ˙ / ω is developed. A systematic method is developed to identify the correct level of transient damping.