Damping and stiffness of particulate SiC-InSn composite

摘要

Metal matrix composites of silicon carbide particles inindium-tin alloy were fabricated with the aim of achieving a high value of the product of stiffness and viscoelastic damping tan delta,without excess density.Stiffness and viscoelastic damping were measured over a wide range of frequency.For monodisperse 40% by volume SiC,and for hierarchical 60% by volume Sic the composite damping increased compared with thematrix at frequencies above 100Hz.Composite shear modulus was almost a factor two greater than matrix for 40% and a factor of four greater than that of matrix for 60%.The product of stiffness and damping exceeds that of well-known materials including polymer damping layers.Hashin-Shtrikman analysis modelled the observedstiffness increaese.The damping increase at higher frequency cannot be accounted for by a purely mechanical composite model;it is attributed to thermoelastic coupling and an increase in matrix dislocations during fabrication.