Ultrasonics: A Technique of Material Characterization

The changes in microstructural features and physical properties of ceramic matrix composite bonding tools under ultrasonic service

“…The characteristics of ultrasonic energy strongly depends strongly on the medium where the wave is travelling through [5]. A presence of discontinuity, like cracks, pores and flaws, along the wave path can reflect and refract the wave motion, then the information of defect site, orientation, size and other microstructural features can be collected.…”

“…Assuming a particle and its neighbouring particles are in equilibrium and they are under interatomic force. The energy travels through most medium in the form of wave due to the displaced or deformed particles according to vibration under elastic service [4,5]. Ultrasonic action benefits the wire bonding in the term of its low temperature.…”

Phasor Wave-Field Simulation Providing Direct Access to Instantaneous Frequency: A Demonstration for a Damped Elastic Wave Simulation

“…At ultrasound frequencies, velocity proportional damping, which scales with the square of the frequency is frequently the dominating damping mechanism. Examples for this behavior are liquids (thermoelastic relaxation, shear, and bulk viscosity) and many solid materials (thermoelastic relaxation, phonon-phonon, and electron-phonon interaction) [10]. Therefore, the following expression is used in all following examples:…”

“…Elastodynamic wave propagation [1] is of crucial importance on a broad spectrum of length scales: starting in the kilometer range, from earth science including earthquake research and geophysical exploration [2][3][4], going down the scale to the millimeter and sub-millimeter range in medical diagnosis and therapy [5,6], sensors and actuators [7][8][9], material science [10][11][12], product and process monitoring [13][14][15], approaching the smallest scale, in non-destructive testing of microelectronic and nanoelectronic components [16,17] phononic crystals and hypersound propagation [18]. In many cases, damping of elastic waves is significant and desired; hence, it must be considered in the simulation of wave propagation phenomena [19][20][21].…”

Ultrasonic testing of grain distortion direction in cold formed aluminium profile

“…Ultrasonic velocity is an important acoustic parameter in material characterization. It is the parameter that correlates to structural inhomogenities, elastic parameter, precipitates, dislocations, phase transformations, porosity and cracks, concentration of different components of alloys, vacancies in lattice sites, size of the nanoparticles in nano-structured materials, electrical resistivity, specific heat, thermal conductivity and other thermoplastical properties of the materials depending upon the different physical conditions [1,2].…”