Pop-in statistics from nanoindentation with spherical indenters are used to determine the stress required to activate dislocation sources in twin boundaries (TBs) in copper and its alloys. The TB source activation stress is smaller than that needed for bulk single crystals, irrespective of the indenter size, dislocation density and stacking fault energy. Because an array of pre-existing Frank partial dislocations is present at a TB, we propose that dislocation emission from the TB occurs by the Frank partials splitting into Shockley partials moving along the TB plane and perfect lattice dislocations, both of which are mobile. The proposed mechanism is supported by recent high resolution transmission electron microscopy images in deformed nanotwinned (NT) metals and may help to explain some of the superior properties of nanotwinned metals (e.g. high strength and good ductility), as well as the process of detwinning by the collective formation and motion of Shockley partial dislocations along TBs.
Li, Juan, et al. "Quantitative insights into the dislocation source behavior of twin boundaries suggest a new dislocation source mechanism." Journal of Materials Research, vol. 36, no. 10, May. 2021. https://doi.org/10.1557/s43578-021-00253-y
Li, Juan, Pharr, G. M., & Kirchlechner, C. (2021). Quantitative insights into the dislocation source behavior of twin boundaries suggest a new dislocation source mechanism. Journal of Materials Research, 36(10). https://doi.org/10.1557/s43578-021-00253-y
Li, Juan, Pharr, G. M., and Kirchlechner, C., "Quantitative insights into the dislocation source behavior of twin boundaries suggest a new dislocation source mechanism," Journal of Materials Research 36, no. 10 (2021), https://doi.org/10.1557/s43578-021-00253-y
@article{osti_1850379,
author = {Li, Juan and Pharr, G. M. and Kirchlechner, C.},
title = {Quantitative insights into the dislocation source behavior of twin boundaries suggest a new dislocation source mechanism},
annote = {Abstract Pop-in statistics from nanoindentation with spherical indenters are used to determine the stress required to activate dislocation sources in twin boundaries (TBs) in copper and its alloys. The TB source activation stress is smaller than that needed for bulk single crystals, irrespective of the indenter size, dislocation density and stacking fault energy. Because an array of pre-existing Frank partial dislocations is present at a TB, we propose that dislocation emission from the TB occurs by the Frank partials splitting into Shockley partials moving along the TB plane and perfect lattice dislocations, both of which are mobile. The proposed mechanism is supported by recent high resolution transmission electron microscopy images in deformed nanotwinned (NT) metals and may help to explain some of the superior properties of nanotwinned metals (e.g. high strength and good ductility), as well as the process of detwinning by the collective formation and motion of Shockley partial dislocations along TBs. Graphic abstract},
doi = {10.1557/s43578-021-00253-y},
url = {https://www.osti.gov/biblio/1850379},
journal = {Journal of Materials Research},
issn = {ISSN 0884-2914},
number = {10},
volume = {36},
place = {United States},
publisher = {Materials Research Society},
year = {2021},
month = {05}}