Understanding Plastic Deformation in Thermal Glasses from Single-Soft-Spot Dynamics

Schoenholz, Samuel S.; Liu, A. J.; Riggleman, Robert A.; Rottler, Jörg

doi:10.1103/physrevx.4.031014

Cited by 62 publications

(84 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This idea is consistent with the fact that FDR-like behavior is emerging at the highest driving rate, where correlations between plastic events and soft spots are reduced [25] and would deserve further attention in future work.…”

Section: Discussionsupporting

confidence: 83%

Plastic response and correlations in athermally sheared amorphous solids

2016

Self Cite

View full text Add to dashboard Cite

The onset of irreversible deformation in low-temperature amorphous solids is due to the accumulation of elementary events, consisting of spacially and temporally localized atomic rearrangements involving only a few tens of atoms. Recently, numerical and experimental work addressed the issue of spatio-temporal correlations between these plastic events. Here, we provide further insight into these correlations by investigating, via molecular dynamics (MD) simulations, the plastic response of a two-dimensional amorphous solid to artificially triggered local shear transformations. We show that while the plastic response is virtually absent in as-quenched configurations, it becomes apparent if a shear strain was previously imposed on the system. Plastic response has a four-fold symmetry which is characteristic of the shear stress redistribution following the local transformation. At high shear rate we report evidence for a fluctuation-dissipation relation, connecting plastic response and correlation, which seems to break down if lower shear rates are considered.

show abstract

Section: Discussionsupporting

confidence: 83%

Plastic response and correlations in athermally sheared amorphous solids

2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Structural inhomogeneity [5][6][7][8][9][10] usually leads to dynamic heterogeneity [11][12][13][14][15] which is closely correlated with the viscoelasticity and plasticity of MGs [16], both facts of engineering importance and scientific curiosity. Unraveling the atomic-scale structure-dynamic relationship is a paramount challenge [17][18][19][20][21][22] as well as a pressing necessity towards eventual applications of MGs [23].…”

Section: Introductionmentioning

confidence: 99%

Transition from stress-driven to thermally activated stress relaxation in metallic glasses

et al. 2016

View full text Add to dashboard Cite

The short-range ordered, but long-range disordered structure of metallic glasses yields strong structural and dynamic heterogeneities. Stress relaxation is a technique to trace the evolution of stress in response to a fixed strain, which reflects the dynamic features phenomenologically described by the Kohlrausch-Williams-Watts (KWW) equation. The KWW equation describes a broad distribution of relaxation times with a small number of empirical parameters, but it does not arise from a particular physically motivated mechanistic picture. Here we report an anomalous two-stage stress relaxation behavior in a Cu 46 Zr 46 Al 8 metallic glass over a wide temperature range and generalize the findings in other compositions. Thermodynamic analysis identifies two categories of processes: a fast stress-driven event with large activation volume and a slow thermally activated event with small activation volume, which synthetically dominates the stress relaxation dynamics. Discrete analyses rationalize the transition mechanism induced by stress and explain the anomalous variation of the KWW characteristic time with temperature. Atomistic simulations reveal that the stress-driven event involves virtually instantaneous short-range atomic rearrangement, while the thermally activated event is the percolation of the fast event accommodated by the long-range atomic diffusion. The insights may clarify the underlying physical mechanisms behind the phenomenological description and shed light on correlating the hierarchical dynamics and structural heterogeneity of amorphous solids.

show abstract

“…Later, Falk and Langer proposed a dynamical mean-field theory of low-temperature shear deformation in amorphous solids in terms of the shear transformation zones, which accounts for many of the features seen in simulations, including strain hardening and yield stress [6]. A number of studies considered various criteria in order to identify regions susceptible to plastic rearrangement by examining the local density [7], elastic moduli [8][9][10], short range order [11,12], and "soft spots" from the low-frequency vibrational modes [13][14][15]. Athermal quasistatic simulations have clearly shown that heterogeneous plastic flow of two-dimensional amorphous solids involves quadrupolar localized rearrangements and system spanning shear bands [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Plastic deformation of a model glass induced by a local shear transformation

Priezjev

2015

Phys. Rev. E

View full text Add to dashboard Cite

The effect of a local shear transformation on plastic deformation of a three-dimensional amorphous solid is studied using molecular dynamics simulations. We consider a spherical inclusion, which is gradually transformed into an ellipsoid of the same volume and then converted back into the sphere. It is shown that at sufficiently large strain amplitudes, the deformation of the material involves localized plastic events that are identified based on the relative displacement of atoms before and after the shear transformation. We find that the density profiles of cage jumps decay away from the inclusion, which correlates well with the radial dependence of the local deformation of the material. At the same strain amplitude, the plastic deformation becomes more pronounced in the cases of weakly damped dynamics or large time scales of the shear transformation. We show that the density profiles can be characterized by the universal function of the radial distance multiplied by a dimensionless factor that depends on the friction coefficient and the time scale of the shear event.

show abstract

Understanding Plastic Deformation in Thermal Glasses from Single-Soft-Spot Dynamics

Cited by 62 publications

References 24 publications

Plastic response and correlations in athermally sheared amorphous solids

Plastic response and correlations in athermally sheared amorphous solids

Transition from stress-driven to thermally activated stress relaxation in metallic glasses

Plastic deformation of a model glass induced by a local shear transformation

Contact Info

Product

Resources

About