A statistical model for predicting size effects on the yield strength in dislocation-mediated crystal plasticity

A unified statistical dislocation-mediated crystal plasticity model is proposed to understand how the sample size affects the yield strength of metals in different crystal systems, namely, single crystals, columnar-grain structured thin films, and polycrystals. The model takes into account the randomness of the pre-existing dislocation network, grain orientation, and grain size to predict the crystal strength as a function of the extrinsic (i.e. sample dimensions) and intrinsic (i.e. microstructural dimensions) length scales. The model is shown to rigorously capture the effect of size across all three crystal systems, i.e. convergence, scatter and overall trend of the strength, and the results are in good agreement with published experimental and simulation results. The developed model provides an accurate and efficient approach to predict the yield strength in metals.

Automated summary

The proposed unified statistical dislocation-mediated crystal plasticity model considers the randomness of pre-existing dislocation network, grain orientation, and grain size to predict the strength of metals in different crystal systems. The model rigorously captures the effect of size on strength across all three crystal systems and shows good agreement with experimental results, providing an accurate and efficient approach to predict yield strength in metals.