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- A random critical point separates brittle and ductile yielding transitions in amorphous materials doi link

Auteur(s): Ozawa M., Berthier L., Biroli Giulio, Rosso Alberto, Tarjus Gilles

(Article) Publié: Proceedings Of The National Academy Of Sciences Of The United States Of America, vol. p.6656 (2018)
Texte intégral en Openaccess : arxiv


Ref HAL: hal-01825140_v1
Ref Arxiv: 1803.11502
DOI: 10.1073/pnas.1806156115
WoS: 000436245000061
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Résumé:

We combine an analytically solvable mean-field elasto-plastic model with molecular dynamics simulations of a generic glass-former to demonstrate that, depending on their preparation protocol, amorphous materials can yield in two qualitatively distinct ways. We show that well-annealed systems yield in a discontinuous brittle way, as metallic and molecular glasses do. Yielding corresponds in this case to a first-order nonequilibrium phase transition. As the degree of annealing decreases, the first-order character becomes weaker and the transition terminates in a second-order critical point in the universality class of an Ising model in a random field. For even more poorly annealed systems, yielding becomes a smooth crossover, representative of the ductile rheological behavior generically observed in foams, emulsions, and colloidal glasses. Our results show that the variety of yielding behavior found in amorphous materials does not result from the diversity of particle interactions or microscopic dynamics {\it per se}, but is instead unified by carefully considering the role of the initial stability of the system.



Commentaires: 15 pages, 14 figures. V2: Accepted for publication in Proc. Natl. Acad. Sci. USA. Réf Journal: Proc. Natl. Acad. Sci. USA 115, 6656 (2018)