Interfaces in crystalline materials

By K. Aifantis. 2009

1,118 citations recorded by the source corpus.

Abstract As the scale of consideration in materials decreases to the micron and sub-micron scales, the effect of internal surfaces on the plastic flow becomes dominating. To explicitly account for interfaces and grain boundaries a gradient plasticity framework, enhanced with a separate interface energy term, has been developed. This interface energy depends on the plastic strain at the interface and defines an interface yield-like criterion which indicates the stress at which the interface begins to deform plastically. Experimentally this interfacial yielding is captured through nanoindentation experiments near the grain boundary of crystalline materials, namely Nb. Fitting the theoretical analytical expression to the experimental data allows the determination of the key material parameters; for Nb it gives the internal length to be approximately 1.4 μm, and in fact for pure (single phase) materials the dislocation source distance is approximated as 1.5 μm. In order to further render the interface-dislocation interactions, discrete dislocation dynamics simulations are performed for a micron-scale tri-crystal with rigid/non-deforming grain boundaries. The resulting strain distribution profile from the simulation coincides with the predicted plastic strain of the gradient plasticity framework, while the best fit results when the internal length in the analytical expression is chosen to be the same as the value of the dislocation source distance used in the simulation. Hence, the gradient plasticity model that considers an interface energy term has been validated using experimental and numerical investigations.

Subfields: Materials Chemistry, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/55e58a63962445d2374728bf14808b560d27d8df

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In Materials Chemistry

In Mechanics of Materials

Citations in the corpus

Segregation-driven grain boundary spinodal decomposition as a pathway for phase nucleation in a high-entropy alloy (2019, background): “They are the most ubiquitous type of planar imperfections in polycrystalline materials [10].”
Nanodisturbances in deformed Gum Metal (2006, background): “Intergrain sliding in highangle grain boundaries occurs through either local shear events [18–21] or movements of grain boundary dislocations [11,18,22,23].”
Mechanical behavior of Σ tilt grain boundaries in nanoscale Cu and Al: A quasicontinuum study (2005, background): “, a process in which a GB atom transfers directly from one grain to another without the creation of point defects [1,22].”
Stress-driven migration of symmetrical 〈1 0 0〉 tilt grain boundaries in Al bicrystals (2009, positive): “[8] have analyzed the Frank–Bilby equation [33] for the dislocation content of grain boundaries.”
Phase field modeling of defects and deformation (2010, methodology): “To avoid dealing with chemical and structural variations across an interface, which could be quite complex on the atomic scale [159], Gibbs formulated a simple phenomenological approach by introducing a hypothetical mathematical dividing surface [160,161].”
Phase stability and structural features of matrix-embedded hardening precipitates in Al-Mg-Si alloys in the early stages of evolution (2007, methodology): “This is analogous to the definition used by Sutton and Balluffi [21] for a commensurate interface.”