Size effect on the strength of micron-sized polycrystals – A dislocation dynamics simulation study

 The effects of grain size (d), specimen size (t) and initial dislocation density on the strength of micron-sized polycrystals are simulated by two-dimensional dislocation dynamics. The results show that the continuum phenomenon of “smaller being weaker” effect for 1 < t/d ⪝⪝ 3 occurs only when the initial dislocation density is high. When t/d < 1 with high initial dislocation density, or when the initial dislocation density is low regardless of t/d, the opposite “smaller being stronger” effect occurs.