Internal-friction mapping on solids by resonance ultrasound microscopy

An internal-friction microscopy is developed for quantitatively determining material damping on a local surface area by measuring vibrational attenuation of an isolated langasite oscillator point contacting the material. Noncontacting measurement of the resonance frequency and attenuation coefficient of the longitudinal vibration of the oscillator has been achieved with a line antenna, providing high sensitivity to the modulus and damping in the local contacting area. Formulation of the relationship between a material's local internal friction and attenuation of the resonator system is proposed using the generalized Hertzian-contact model. Results on a dual-phase stainless steel and a CuNbTi composite are shown. © 2006 American Institute of Physics.Ogi H., Niho H., Hirao M. "Internal-friction mapping on solids by resonance ultrasound microscopy", Applied Physics Letters, 88(14), 141110 (2006) https://doi.org/10.1063/1.2194479