Relations between stress drops and acoustic emission measured during mechanical loading
| Autor: | Noam Zreihan, Eilon Faran, Eduard Vives, Doron Shilo, Antoni Planes |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) 02 engineering and technology Acoustic wave 021001 nanoscience & nanotechnology 01 natural sciences Upper and lower bounds Stress (mechanics) Amplitude Acoustic emission 0103 physical sciences General Materials Science Atomic physics 010306 general physics 0210 nano-technology Crystal twinning Energy (signal processing) Mechanical energy |
| Zdroj: | Physical Review Materials. 3 |
| ISSN: | 2475-9953 |
| DOI: | 10.1103/physrevmaterials.3.043603 |
| Popis: | Avalanche events occur during mechanical loading of many material systems and are characterized by stress drops and acoustic emission (AE). Stress drops are directly related to the macroscopic response of the investigated material, but their detection capability is restricted to relatively large and slow events. AE measurements can detect events with smaller amplitude and shorter duration, but their energy and duration are not directly related to the change of the system. In this paper, we present simultaneous measurements of stress drops and AE during mechanically induced twin boundary motion in Ni-Mn-Ga. We found that the probability of finding an AE event during a stress drop is $\ensuremath{\sim}100$ times higher than between stress drops. Analysis of the relations between mechanical energy drops $\mathrm{\ensuremath{\Delta}}{U}_{m}$ and acoustic emitted energy ${E}_{\mathrm{AE}}$, on the level of individual events, reveals the existence of a lower bound for ${E}_{\mathrm{AE}}$, which is approximately proportional to $\mathrm{\ensuremath{\Delta}}{U}_{m}$. These results imply that the macroscopic stress changes generate acoustic waves, which contribute a well-defined amount of energy that is equal to the lower bound function. Furthermore, smaller scale events that are related to microscopic subprocesses by which the twin boundary moves generate additional AE energy. The latter contribution displays a power-law distribution, which implies that these processes are close to criticality. |
| Databáze: | OpenAIRE |
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