Macroscopic frictional sliding emerges from atomic-scale interactions and processes at the contact interface, but bridging the gap between micro and macro scales still remains an unsolved challenge. Direct imaging of the contact surface and simultaneous measurement of stress fields during macroscopic frictional slip revealed the formation of crack precursors, questioning the traditional picture of frictional contacts described in terms of a single degree of freedom. Here we study the onset of frictional slip on the atomic scale by simulating the motion of an aluminum block pushed by a slider on a copper substrate. We show the formation of dynamic slip front propagation and precursory activity that resemble macroscopic observations. The analysis of stress patterns during slip, however, reveals subtle effects due to the lattice structures that hinder a direct application of linear elastic fracture mechanics. Our results illustrate that dynamic front propagation arises already on the atomic scales and shed light on the connections between atomic-scale and macroscopic friction.

Atomic-Scale Front Propagation at the Onset of Frictional Sliding / S. Bonfanti, A. Taloni, C. Negri, A.L. Sellerio, N. Manini, S. Zapperi. - In: THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS. - ISSN 1948-7185. - 8:21(2017 Nov 02), pp. 5438-5443. [10.1021/acs.jpclett.7b02414]

Atomic-Scale Front Propagation at the Onset of Frictional Sliding

S. Bonfanti
Primo
;
A. Taloni;C. Negri;A.L. Sellerio;N. Manini;S. Zapperi
Ultimo
2017

Abstract

Macroscopic frictional sliding emerges from atomic-scale interactions and processes at the contact interface, but bridging the gap between micro and macro scales still remains an unsolved challenge. Direct imaging of the contact surface and simultaneous measurement of stress fields during macroscopic frictional slip revealed the formation of crack precursors, questioning the traditional picture of frictional contacts described in terms of a single degree of freedom. Here we study the onset of frictional slip on the atomic scale by simulating the motion of an aluminum block pushed by a slider on a copper substrate. We show the formation of dynamic slip front propagation and precursory activity that resemble macroscopic observations. The analysis of stress patterns during slip, however, reveals subtle effects due to the lattice structures that hinder a direct application of linear elastic fracture mechanics. Our results illustrate that dynamic front propagation arises already on the atomic scales and shed light on the connections between atomic-scale and macroscopic friction.
Settore FIS/03 - Fisica della Materia
Size effects in fracture and plasticity
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/528728
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