Temperature-activated dislocation avalanches signaling brittle-to-ductile transition in BCC micropillars
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arXiv
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| Autori principali: | , , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866914350485209088 |
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| author | Li, Yang Lalani, Inam Maron, Matthew Hixson, William Wang, Biao Ghoniem, Nasr Po, Giacomo |
| author_facet | Li, Yang Lalani, Inam Maron, Matthew Hixson, William Wang, Biao Ghoniem, Nasr Po, Giacomo |
| contents | 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2409_16987 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Temperature-activated dislocation avalanches signaling brittle-to-ductile transition in BCC micropillars Li, Yang Lalani, Inam Maron, Matthew Hixson, William Wang, Biao Ghoniem, Nasr Po, Giacomo Materials Science 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. |
| title | Temperature-activated dislocation avalanches signaling brittle-to-ductile transition in BCC micropillars |
| topic | Materials Science |
| url | https://arxiv.org/abs/2409.16987 |