Temperature-activated dislocation avalanches signaling brittle-to-ductile transition in BCC micropillars
摘要
We carry out strain-controlled in-situ compression experiments of micron-sized tungsten (W) micropillars in the temperature range 300-900 K, together with simulations of three-dimensional discrete dislocation dynamics (DDD) at the same scale. Two distinct regimes are observed. At low temperatures, plastic deformation appears smooth, both temporally and spatially. Stress fluctuations are consistent with a Wiener stochastic process resulting from uncorrelated dislocation activity within the pillars. However, high-temperature stress fluctuations are highly correlated and exhibit features of self-organized criticality (SOC), with deformation located within well-defined slip bands. The high-temperature stress relaxation statistics are consistent with a thermally activated nucleation process from the surface. The nature of the transition between the two regimes is a manifestation of the brittle to ductile transition in BCC metals.
引用
@article{arxiv.2409.16987,
title = {Temperature-activated dislocation avalanches signaling brittle-to-ductile transition in BCC micropillars},
author = {Yang Li and Inam Lalani and Matthew Maron and William Hixson and Biao Wang and Nasr Ghoniem and Giacomo Po},
journal= {arXiv preprint arXiv:2409.16987},
year = {2026}
}
备注
5 pages, 4 figures