Acoustic processes in materials
- PDF / 2,605,062 Bytes
- 5 Pages / 585 x 783 pts Page_size
- 116 Downloads / 304 Views
Introduction The generation and probing of acoustic waves of different types, such as bulk longitudinal or transverse/shear waves and surface/Rayleigh waves, are used in many well-established applications, including nondestructive testing and material characterization,1 signal processing,2 dry laser cleaning,3 chemical sensing,4 and manipulation of fluid flow in microfluidics devices.5 New opportunities that could expand the range of acoustically enabled applications are emerging from exploratory studies that report the ability of acoustic energy to drive rearrangement of crystal defects,6,7 induce crystallization in amorphous materials and thin films,8,9 and affect atomic rearrangements10,11 and chemical reactions12–15 on surfaces. “Traditional” application areas, such as nondestructive detection/evaluation of material heterogeneities and defects, are also experiencing a revival due to the development of new techniques that enable in situ monitoring of subsurface microstructure evolution with high temporal and spatial resolutions, as well as advanced approaches that take advantage of nonlinear acoustic effects to achieve a dramatic boost in the structural sensitivity and spatial resolution of acoustic microscopy. Many of these new developments have the potential for making a strong impact on acoustically assisted material processing and in situ/in operando material characterization. The articles in this issue of MRS Bulletin are focused on some of the most promising and intriguing developments in
the area of acoustically enabled materials synthesis, processing, and characterization, which are likely to be of interest to a broad expanse within the materials R&D communities.
Advanced methods of acoustic materials characterization Recent improvements in the sensitivity and spatial resolution of acoustic nondestructive evaluation methods are largely achieved through utilization of nonlinear acoustic effects, as discussed in the article by Zaitsev16 in this issue. Starting from a brief overview of conventional linear acoustic diagnostic techniques (pulse-echo, resonance-based methods), the article proceeds with a broad overview of different types of nonlinear acoustic response and provides examples of the manifestation of nonlinear effects in acoustic probing of heterogeneous materials that exhibit a structure-induced “mesoscopic” acoustic nonlinearity. The applications of nonlinear acoustic probing range from characterization of nanoscale heterogeneities, such as dislocation structures, to identification of microcracks and granular materials, to macroscopic nondestructive testing of engineering structures, and to seismic studies performed at a scale of kilometers. Among the many methods for the generation of acoustic waves, photoacoustic techniques stand out for their noncontact nature and flexibility, enabling creative design of experimental setups tuned to practical application needs. An example of
Leonid V. Zhigilei, Department of Materials Science and Engineering, University of Virginia, USA; [email protected] Henr
Data Loading...
