Micro-bending tests: A comparison between three-dimensional discrete dislocation dynamics simulations and experiments

By C. Motz, D. Weygand, J. Senger, Peter Gumbsch. 2008

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Abstract Discrete dislocation dynamics simulations in three dimensions are performed on micro-sized bending beams and the results are compared with experiments. A strong size dependence of the flow stress σ f (or bending moment) is found. The flow stress scales approximately inversely with the beam thickness t. The simulations show that the dislocation structure exhibits pronounced pile-ups around the neutral plane of the beam. The back stress from these pile-ups on the dislocation sources is analyzed by means of an analytical pile-up model. It is shown that the scaling behavior σ f ∝ t - 1 can be explained by a combination of pile-up and source size limitation. Subsequently, the applicability of strain gradient plasticity models on micro-bending is discussed.

Subfields: Materials Chemistry, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/38235ca1bbd381e75ece6b70f9c6ccb519a5432a