TY - JOUR
T1 - Scaling of relaxation and excess entropy in plastically deformed amorphous solids
AU - Lawrence Galloway, K.
AU - Ma, Xiaoguang
AU - Keim, Nathan C.
AU - Jerolmack, Douglas J.
AU - Yodh, Arjun G.
AU - Arratia, Paulo E.
N1 - Funding Information:
ACKNOWLEDGMENTS. We thank Kevin Aptowicz, Piotr Habdas, Peter Collings, Remi Dreyfus, Chandan Kumar Mishra, Alexis de la Cotte, Analisa Hill, Sophie Ettinger, Wei-shao Wei, Andrea Liu, Doug Durian, Sèbastien Kosgodagan Acharige, and Xiaozhou He for helpful discussions. This work was primarily supported by the NSF through Penn Materials Research Science and Engineering Center Grant DMR-1720530, including its Optical Microscopy Shared Experimental Facility. Additionally, X.M. and A.G.Y. were supported by NSF Grant DMR16-07378 and NASA Grant 80NSSC19K0348. K.L.G., D.J.J., and P.E.A. were supported by Army Research Office Grant W911-NF-16-1-0290.
PY - 2020/6/2
Y1 - 2020/6/2
N2 - When stressed sufficiently, solid materials yield and deform plastically via reorganization of microscopic constituents. Indeed, it is possible to alter the microstructure of materials by judicious application of stress, an empirical process utilized in practice to enhance the mechanical properties of metals. Understanding the interdependence of plastic flow and microscopic structure in these nonequilibrium states, however, remains a major challenge. Here, we experimentally investigate this relationship, between the relaxation dynamics and microscopic structure of disordered colloidal solids during plastic deformation. We apply oscillatory shear to solid colloidal monolayers and study their particle trajectories as a function of shear rate in the plastic regime. Under these circumstances, the strain rate, the relaxation rate associated with plastic flow, and the sample microscopic structure oscillate together, but with different phases. Interestingly, the experiments reveal that the relaxation rate associated with plastic flow at time t is correlated with the strain rate and sample microscopic structure measured at earlier and later times, respectively. The relaxation rate, in this nonstationary condition, exhibits power-law, shear-thinning behavior and scales exponentially with sample excess entropy. Thus, measurement of sample static structure (excess entropy) provides insight about both strain rate and constituent rearrangement dynamics in the sample at earlier times.
AB - When stressed sufficiently, solid materials yield and deform plastically via reorganization of microscopic constituents. Indeed, it is possible to alter the microstructure of materials by judicious application of stress, an empirical process utilized in practice to enhance the mechanical properties of metals. Understanding the interdependence of plastic flow and microscopic structure in these nonequilibrium states, however, remains a major challenge. Here, we experimentally investigate this relationship, between the relaxation dynamics and microscopic structure of disordered colloidal solids during plastic deformation. We apply oscillatory shear to solid colloidal monolayers and study their particle trajectories as a function of shear rate in the plastic regime. Under these circumstances, the strain rate, the relaxation rate associated with plastic flow, and the sample microscopic structure oscillate together, but with different phases. Interestingly, the experiments reveal that the relaxation rate associated with plastic flow at time t is correlated with the strain rate and sample microscopic structure measured at earlier and later times, respectively. The relaxation rate, in this nonstationary condition, exhibits power-law, shear-thinning behavior and scales exponentially with sample excess entropy. Thus, measurement of sample static structure (excess entropy) provides insight about both strain rate and constituent rearrangement dynamics in the sample at earlier times.
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U2 - 10.1073/pnas.2000698117
DO - 10.1073/pnas.2000698117
M3 - Article
C2 - 32430317
AN - SCOPUS:85085904492
VL - 117
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 22
M1 - 2000698117
ER -