A statistical theory was proposed to describe the jerky deformation of micron-sized crystal pillars. The probability for a specimen surviving the applied load without generating a strain burst of a given order was analytically expressed in terms of the nucleation rate of that burst. The survival probability could be measured from an ensemble of macroscopically similar deformation experiments to obtain the nucleation rate. From experiments on aluminium pillars, the nucleation rate was found to increase with the pillar size and to decrease with the burst order, indicating that more sources were present in a larger specimen and that the available nucleating sources were progressively exhausted by the occurrence of bursts. The activation volume measured was roughly independent of the pillar size and burst order, indicating a constant mechanism for burst nucleation.

Stochastic Theory for Jerky Deformation in Small Crystal Volumes with Pre-Existing Dislocations. K.S.Ng, A.H.W.Ngan: Philosophical Magazine, 2008, 88[5], 677-88