Scaling in the Local Strain-Rate Field during Jerky Flow in an Al-3%Mg Alloy

Autor: Mikhail Lebyodkin, Youcef Bougherira, Tatiana Lebedkina, Denis Entemeyer
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Metals, Vol 10, Iss 1, p 134 (2020)
Druh dokumentu: article
ISSN: 2075-4701
DOI: 10.3390/met10010134
Popis: Jerky flow in alloys, or the Portevin-Le Chatelier effect, presents an outstanding example of self-organization phenomena in plasticity. Recent acoustic emission investigations revealed that its microscopic dynamics is governed by scale invariance manifested as power-law statistics of intermittent events. As the macroscopic stress serrations show both scale invariance and characteristic scales, the micro-macro transition is an intricate question requiring an assessment of intermediate behaviors. The first attempt of such an investigation is undertaken in the present paper by virtue of a one-dimensional (1D) local extensometry technique and statistical analysis of time series. The data obtained complete the missing link and bear evidence to a coexistence of characteristic large events and power laws for smaller events. The scale separation is interpreted in terms of the phenomena of self-organized criticality and synchronization in complex systems. Furthermore, it is found that both the stress serrations and local strain-rate bursts agree with the so-called fluctuation scaling related to general mathematical laws and unifying various specific mechanisms proposed to explain scale invariance in diverse systems. Prospects of further investigations including the duality manifested by a wavy spatial organization of the local bursts of plastic deformation are discussed.
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