Acoustic emission spectra and statistics of dislocation movements in Fe40Mn40Co10Cr10 high entropy alloys

• Published in: Journal of applied physics Vol. 132; no. 8
• Main Authors: Chen, Yan, Tang, Ke, Gou, Boyuan, Jiang, Feng, Ding, Xiangdong, Salje, Ekhard K. H.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 28.08.2022
• Subjects: Acoustic emission testing; Applied physics; Austenitic stainless steels; Avalanches; Emission spectra; High entropy alloys; Inhomogeneity
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/5.0098813

The defining feature of high-entropy alloys (HEAs) is their unprecedented degree of compositional inhomogeneity which influences their dislocation movements. We demonstrate differences between a HEA (Fe40Mn40Co10Cr10) and a conventional solution alloy (316L stainless steel) using acoustic emission (AE) spectroscopy. AE measurements under tension show the coexistence of two avalanche processes in Fe40Mn40Co10Cr10 HEA, whereby one avalanche process relates to the movement of dislocations and the other to detwinning/twinning processes. These two avalanche processes exhibit two branches of the E ∼ A2 correlation. The dislocation movements in Fe40Mn40Co10Cr10 HEA show systematically longer durations compared with the equivalent dislocation movements in the 316L stainless steel and a bias toward faster waiting times for subsequent dislocation movements. The aftershock rate, as identified by the Omori law, is the same for the two materials.