Assessment of Internal Stresses Using Dislocation Dipole Heights in Cyclically Deformed [001] Copper Single Crystals
There have been a number of studies on dipole separations in cyclically deformed FCC single crystals in single slip while there are no such studies in multiple slip. The dipole heights provide insight into the presence of long-range internal stresses (LRIS). In this study, we investigated how LRIS c...
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MDPI AG
2020-04-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/10/4/512 |
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| author | Roya Ermagan Maxime Sauzay Michael Ernest Kassner |
| author_facet | Roya Ermagan Maxime Sauzay Michael Ernest Kassner |
| author_sort | Roya Ermagan |
| collection | DOAJ |
| description | There have been a number of studies on dipole separations in cyclically deformed FCC single crystals in single slip while there are no such studies in multiple slip. The dipole heights provide insight into the presence of long-range internal stresses (LRIS). In this study, we investigated how LRIS compare with the single slip studies through measuring the dislocation of dipole heights. [001] oriented copper single crystals were cyclically deformed in strain-control to saturation at ambient temperature. Transmission electron microscopy (TEM) confirms a labyrinth dislocation microstructure with high dislocation density walls and low dislocation density channels. The maximum dipole heights under the saturation stress were approximately independent of location, being nearly equal in the walls and within the channels. This, by itself, supports a uniform stress across the microstructure and low long-range internal stresses. The maximum value for dipole heights suggests dipole strengths (local stresses) that are about a factor of 2.4 higher than the applied stress based on the usual athermal equations. Considering the small “extra” stress that may be provided by tripoles or small dislocation pile-ups, a nearly homogenous stress distribution with only small internal stresses may be present, which is consistent with the observation of uniform dipole height across the heterogeneous dislocation microstructure. This observation that the stress state appears to be homogenous and higher than the applied stress has also been reported in the case of cyclically deformed metals in single slip. |
| first_indexed | 2024-03-10T20:26:56Z |
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| id | doaj.art-2eb7a6877afa45eb98e7fa6ea683c085 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T20:26:56Z |
| publishDate | 2020-04-01 |
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| spelling | doaj.art-2eb7a6877afa45eb98e7fa6ea683c0852023-11-19T21:43:55ZengMDPI AGMetals2075-47012020-04-0110451210.3390/met10040512Assessment of Internal Stresses Using Dislocation Dipole Heights in Cyclically Deformed [001] Copper Single CrystalsRoya Ermagan0Maxime Sauzay1Michael Ernest Kassner2Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USACEA Paris-Saclay, DMN-SRMA, Bat. 455, 91191 Gif-sur-Yvette CEDEX, FranceMork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USAThere have been a number of studies on dipole separations in cyclically deformed FCC single crystals in single slip while there are no such studies in multiple slip. The dipole heights provide insight into the presence of long-range internal stresses (LRIS). In this study, we investigated how LRIS compare with the single slip studies through measuring the dislocation of dipole heights. [001] oriented copper single crystals were cyclically deformed in strain-control to saturation at ambient temperature. Transmission electron microscopy (TEM) confirms a labyrinth dislocation microstructure with high dislocation density walls and low dislocation density channels. The maximum dipole heights under the saturation stress were approximately independent of location, being nearly equal in the walls and within the channels. This, by itself, supports a uniform stress across the microstructure and low long-range internal stresses. The maximum value for dipole heights suggests dipole strengths (local stresses) that are about a factor of 2.4 higher than the applied stress based on the usual athermal equations. Considering the small “extra” stress that may be provided by tripoles or small dislocation pile-ups, a nearly homogenous stress distribution with only small internal stresses may be present, which is consistent with the observation of uniform dipole height across the heterogeneous dislocation microstructure. This observation that the stress state appears to be homogenous and higher than the applied stress has also been reported in the case of cyclically deformed metals in single slip.https://www.mdpi.com/2075-4701/10/4/512fatiguecyclic deformationcopper single crystaldislocation dipolesinternal stress |
| spellingShingle | Roya Ermagan Maxime Sauzay Michael Ernest Kassner Assessment of Internal Stresses Using Dislocation Dipole Heights in Cyclically Deformed [001] Copper Single Crystals Metals fatigue cyclic deformation copper single crystal dislocation dipoles internal stress |
| title | Assessment of Internal Stresses Using Dislocation Dipole Heights in Cyclically Deformed [001] Copper Single Crystals |
| title_full | Assessment of Internal Stresses Using Dislocation Dipole Heights in Cyclically Deformed [001] Copper Single Crystals |
| title_fullStr | Assessment of Internal Stresses Using Dislocation Dipole Heights in Cyclically Deformed [001] Copper Single Crystals |
| title_full_unstemmed | Assessment of Internal Stresses Using Dislocation Dipole Heights in Cyclically Deformed [001] Copper Single Crystals |
| title_short | Assessment of Internal Stresses Using Dislocation Dipole Heights in Cyclically Deformed [001] Copper Single Crystals |
| title_sort | assessment of internal stresses using dislocation dipole heights in cyclically deformed 001 copper single crystals |
| topic | fatigue cyclic deformation copper single crystal dislocation dipoles internal stress |
| url | https://www.mdpi.com/2075-4701/10/4/512 |
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