A viscoplastic micromechanical model for the yield strength of nanocrystalline materials

Dislocation nucleation from bicrystal interfaces and grain boundary ledges: Relationship to nanocrystalline deformation

“…Recently, Asaro and Suresh (2005) successfully modeled, via a continuum dislocation approach at the microscopic scale, the size effect in the strain rate sensitivity in terms of the decrease of activation volume for dislocation nucleation with grain size. This effect was also investigated via a micromechanical scheme based on fast Fourier transform (Lebensohn et al, 2007).…”

Correlation between Poisson ratio and Mohr–Coulomb coefficient in metallic glasses

“…Friction coefficients have been established for different granular materials, such as polymers [28,29] ( around 0.2), sand and gravel [30] ( from 0.2 up to 1.0) and bone [31]. The Mohr-Coulomb yield criterion has been also used to explain the results obtained for nanocrystalline materials [32] and = 0.04 has been assumed for grain boundary accommodation processes [33]. It has been suggested [3,22,27] that metallic glasses follow the Mohr-Coulomb criterion, so that the shear strength depends on a combination of tensile/compressive and shear stresses.…”

Role of grain boundary energetics on the maximum strength of nanocrystalline Nickel

“…These efforts have focussed on the ability to describe HallPetch or inverse Hall-Petch effects separately. On the other hand, a continuous approach to describe the transition from Hall-Petch to inverse Hall-Petch is presented by Lebensohn et al (2007) where the size dependency on the yield stress is introduced by a size dependent flow stress constitutive equation.…”