A crystal plasticity analysis of length-scale dependent internal stresses with image effects

Aghababaei, Ramin; Joshi, Shailendra P.

doi:10.1016/j.jmps.2012.07.005

Cited by 6 publications

(2 citation statements)

References 85 publications

(171 reference statements)

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“…Furthermore, the influence of surface roughness parameters, subsurface microstructure, and inhomogeneities such as precipitates or microcracks on the interaction length scale and surface cracking need to be yet investigated [35,61]. In summary, these results highlight a critical need for studying single-and multiasperity contact beyond the elastic limit [62][63][64][65][66][67].…”

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confidence: 97%

Asperity-Level Origins of Transition from Mild to Severe Wear

2018

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Wear is the inevitable damage process of surfaces during sliding contact. According to the well-known Archard's wear law, the wear volume scales with the real contact area and as a result is proportional to the load. Decades of wear experiments, however, show that this relation only holds up to a certain load limit, above which the linearity is broken and a transition from mild to severe wear occurs. We investigate the microscopic origins of this breakdown and the corresponding wear transition at the asperity level. Our atomistic simulations reveal that the interaction between subsurface stress fields of neighboring contact spots promotes the transition from mild to severe wear. The results show that this interaction triggers the deep propagation of subsurface cracks and the eventual formation of large debris particles, with a size corresponding to the apparent contact area of neighboring contact spots. This observation explains the breakdown of the linear relation between the wear volume and the normal load in the severe wear regime. This new understanding highlights the critical importance of studying contact beyond the elastic limit and single-asperity models.

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Asperity-Level Origins of Transition from Mild to Severe Wear

2018

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“…The elastic constants and the magnitude of the Burgers vectors of aluminum are adopted here, i.e., l = 26.3 Gpa, m = 0.33 and b = 0.25 nm. According to many previous works (Bittencourt et al, 2003;Fredriksson and Gudmundson, 2005;Aifantis et al, 2006;Liu et al, 2011;Aghababaei and Joshi, 2012;Mayeur and McDowell, 2013), the bulk material length scale R varies from tens of nanometers to several microns, thus we take an intermediate value here, i.e., R = 0.5 lm. By fitting the numerical simulation results to the experiments data, Hurtado and Ortiz (2012) obtained a value of 90.0 N/m for C 1 of nickel greatly in excess of the corresponding known surface free energy density, which is attributed to the considerable surface damage of the samples in experiments during the manufacturing process.…”

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confidence: 99%

Modeling dislocation absorption by surfaces within the framework of strain gradient crystal plasticity

Peng

Huang

2015

International Journal of Solids and Structures

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a b s t r a c tSurfaces play important roles in plastic deformation of crystals at submicron scale by emitting/absorbing dislocations and hence may contribute to the complicated size effect. To take into account the dislocation absorption on the continuum level, an energetic surface model has been proposed by considering the change of surface energy contributed by the formation of surface steps via dislocation absorption. In combination with the conventional higher-order strain gradient theory for grain interior, a new model for single crystal plasticity has been developed. Within the model, there exists a critical threshold for the onset of dislocation absorption by surfaces, alternatively, an independent yield criterion for surfaces and the microscopic boundary conditions can be obtained naturally. As an example of application, plastic behavior of a thin film under plane constrained shear has been studied. Results demonstrate that surface yield strength strongly depends on the film thickness and the orientation of the activated slip system. Comparison with the strain gradient plasticity models under the conventional microscopic boundary conditions, i.e., the microhard and microfree conditions has also been made. It has been found that the plastic behavior is sensitive to the surface boundary conditions.

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Effect of dislocation absorption by surfaces on strain hardening of single crystalline thin films

Peng

Huang

2017

Arch Appl Mech

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A crystal plasticity analysis of length-scale dependent internal stresses with image effects

Cited by 6 publications

References 85 publications

Asperity-Level Origins of Transition from Mild to Severe Wear

Asperity-Level Origins of Transition from Mild to Severe Wear

Modeling dislocation absorption by surfaces within the framework of strain gradient crystal plasticity

Effect of dislocation absorption by surfaces on strain hardening of single crystalline thin films

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