TY  - JOUR
A1  - Fernandez, Ricardo
A1  - Bruno, Giovanni
A1  - Garces, Gerardo
A1  - Nieto-Luis, H.
A1  - Gonzalez-Doncel, Gaspar
T1  - Fractional brownian motion of dislocations during creep deformation of metals
JF  - Materials science & engineering. A, Structural materials
N2  - 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.
KW  - Creep
KW  - Aluminum alloys
KW  - Dislocation motion
KW  - Diffusion
KW  - Fractal
KW  - structures
Y1  - 2020
U6  - https://doi.org/10.1016/j.msea.2020.140013
SN  - 0921-5093
SN  - 1873-4936
VL  - 796
PB  - Elsevier
CY  - Lausanne
ER  -