Fractional brownian motion of dislocations during creep deformation of metals
- The present work offers an explanation on how the long-range interaction of dislocations influences their movement, and therefore the strain, during creep of metals. It is proposed that collective motion of dislocations can be described as a fractional Brownian motion. This explains the noisy appearance of the creep strain signal as a function of time. Such signal is split into a deterministic and a stochastic part. These terms can be related to two kinds of dislocation motions: individual and collective, respectively. The description is consistent with the fractal nature of strain-induced dislocation structures predicated in previous works. Moreover, it encompasses the evolution of the strain rate during all stages of creep, including the tertiary one. Creep data from Al99.8% and Al3.85%Mg tested at different temperatures and stresses are used to validate the proposed ideas: it is found that different creep stages present different diffusion characters, and therefore different dislocation motion character.
Author details: | Ricardo FernandezORCiD, Giovanni BrunoORCiDGND, Gerardo GarcesORCiD, H. Nieto-Luis, Gaspar Gonzalez-DoncelORCiD |
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DOI: | https://doi.org/10.1016/j.msea.2020.140013 |
ISSN: | 0921-5093 |
ISSN: | 1873-4936 |
Title of parent work (English): | Materials science & engineering. A, Structural materials |
Publisher: | Elsevier |
Place of publishing: | Lausanne |
Publication type: | Article |
Language: | English |
Date of first publication: | 2020/08/05 |
Publication year: | 2020 |
Release date: | 2023/10/19 |
Tag: | Aluminum alloys; Creep; Diffusion; Dislocation motion; Fractal; structures |
Volume: | 796 |
Article number: | 140013 |
Number of pages: | 8 |
Funding institution: | MINECO, Spain [MAT2017-83825-C4-1-R]; Community of Madrid, CAM,; SpainComunidad de Madrid [Y2018/NMT-4668] |
Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
DDC classification: | 5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik |
Peer review: | Referiert |