Crossover from Superdiffusive to Diffusive Mixing in Plastically Deformed Solids

Bellon, Pascal; Averback, Robert S; Odunuga, S.; Li, Y.; Krasnochtchekov, P.; Caro, A.

doi:10.1103/physrevlett.99.110602

Cited by 29 publications

(17 citation statements)

References 15 publications

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“…The understanding of the mechanism could help to explain and classify various athermal atomic transport processes known in the literature such as superdiffusion on solid surfaces 5,14,15,24 , quantum diffusion 4,5,23,32 , transient enhanced diffusion and intermixing 17,31 , transient cluster burrowing 22 , ultrafast adatom island nucleation 24 , coherent ballistic displacement of atoms 16 , the cooperative enhancement of surface roughening 66 , the facilitated intermixing near step edges 67 or the superdiffusive mixing in plastically deformed solids 69 .…”

Section: Discussionmentioning

confidence: 99%

Self-organized transient facilitated atomic transport in Pt∕Al(111)

Süle

2008

The Journal of Chemical Physics

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During the course of atomic transport in a host material, impurity atoms need to surmount an energy barrier driven by thermodynamic bias or at ultra-low temperatures by quantum tunneling. In the present article we demonstrate using atomistic simulations that at ultra-low temperature transient inter-layer atomic transport is also possible without tunneling when the Pt/Al(111) impurity/host system self-organizes itself spontaneously into an intermixed configuration. No such extremely fast athermal concerted process has been reported before at ultra low temperatures. The outlined novel transient atomic exchange mechanism could be of general validity. We find that the source of ultra-low temperature heavy particle barrier crossing is intrinsic and no external bias is necessary for atomic intermixing and surface alloying in Pt/Al although the dynamic barrier height is few eV. The mechanism is driven by the local thermalization of the Al(111) surface in a selforganized manner arranged spontaneously by the system without any external stimulus. The core of the short lived thermalized region reaches the local temperature of ∼ 1000 K (including few tens of Al atoms) while the average temperature of the simulation cell is ∼ 3 K. The transient facilitated intermixing process also takes place with repulsive impurity-host interaction potential leading to negative atomic mobility hence the atomic injection is largely independent of the strength of the impurity-surface interaction. We predict that similar exotic behaviour is possible in other materials as well.

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Section: Discussionmentioning

confidence: 99%

Self-organized transient facilitated atomic transport in Pt∕Al(111)

Süle

2008

The Journal of Chemical Physics

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“…[30][31][32][33][34][35][36] Despite the large number of studies, the underlying deformation-induced mixing processes and the critical factors defining the maximum solubility are still under debate. [33,[37][38][39] Several studies indicate a strong link between the heat of mixing and the degree of supersaturation. In systems with low positive heat of mixing, as for example, Cu-Ag, complete solid solutions are easily reached over the whole composition range during ball milling.…”

Section: Introductionmentioning

confidence: 99%

Deformation‐Induced Supersaturation in Immiscible Material Systems during High‐Pressure Torsion

2016

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The review focuses on the supersaturation process of immiscible elements induced by high-pressure torsion deformation. A variety of investigated material systems offers the systematic analysis of the controlling factors for mechanical intermixing, which are mainly determined by the level of the positive heat of mixing and the deformation behavior. The homogeneity of the deformation process strongly influences the degree of supersaturation. Our results show that the fundamental mixing mechanism during deformation is not necessarily the same in all systems, but depends also on the strength differences of the phases and accordingly the deformation behavior.

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“…This result agrees with a previous study on the dissolution of spherical precipitates using MD computer simulations, which had shown that shear mixing is superdiffusive, and that the strain required to dissolve small spherical precipitates of radius R p scales with 1 / R p , which again is distinct from the 1 / R p 2 scaling for Fickian diffusion. 32 For multilayered structures, for example ARB, the signature of superdiffusive mixing is far more subtle and it could lead to incorrect conclusions being drawn from experimental studies of the mixing process, as we briefly illustrate.…”

Section: B Model Of Shear Mixing: Monte Carlo Simulationsmentioning

confidence: 94%