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Effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applications

An investigation of the mechanical properties of high-purity niobium single crystals is presented. Specimens were cut with different crystallographic orientations from a large grain niobium disk and uniaxial tensile tests were conducted at strain rates between 10$^{-4}$ and 10$^3$ s$^{-1}$. The loga...

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Autores principales: Croteau, J -F, Kulyadi, E Pai, Kale, C, Siu, D, Kang, D, Fontenla, A T Perez, Valdivieso, E García-Tabarés, Bieler, T R, Eisenlohr, P, Solanki, K N, Balint, D, Hooper, P A, Atieh, S, Jacques, N, E Cantergiani
Lenguaje:eng
Publicado: 2020
Materias:
Acceso en línea:https://dx.doi.org/10.1016/j.msea.2020.140258
http://cds.cern.ch/record/2740936
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author Croteau, J -F
Kulyadi, E Pai
Kale, C
Siu, D
Kang, D
Fontenla, A T Perez
Valdivieso, E García-Tabarés
Bieler, T R
Eisenlohr, P
Solanki, K N
Balint, D
Hooper, P A
Atieh, S
Jacques, N
E Cantergiani
author_facet Croteau, J -F
Kulyadi, E Pai
Kale, C
Siu, D
Kang, D
Fontenla, A T Perez
Valdivieso, E García-Tabarés
Bieler, T R
Eisenlohr, P
Solanki, K N
Balint, D
Hooper, P A
Atieh, S
Jacques, N
E Cantergiani
author_sort Croteau, J -F
collection CERN
description An investigation of the mechanical properties of high-purity niobium single crystals is presented. Specimens were cut with different crystallographic orientations from a large grain niobium disk and uniaxial tensile tests were conducted at strain rates between 10$^{-4}$ and 10$^3$ s$^{-1}$. The logarithmic strain rate sensitivity for crystals oriented close to the center of a tensile axis inverse pole figure (IPF) is ~0.14 for all strain rates. The strain at failure (ranging from 0.4 to 0.9) is very sensitive to crystal orientation and maximal at $~10^{-2}$ s$^{-1}$ for crystals oriented close to the center of an IPF. The high anisotropy observed at quasi-static strain rates decreased with increasing strain rate. The activation of multiple slip systems in the dynamic tests could account for this reduction in anisotropy. A transition from strain hardening to softening in the plastic domain was observed at strain rates greater than approximately $6 × 10^{-2}$ s$^{-1}$ for crystals oriented close to the center of a tensile axis IPF. Shear bands were observed in specimens with orientations having similarly high Schmid factors on both and slip families, and they are correlated with reduced ductility. Crystal rotations at fracture are compared for the different orientations using scanning electron microscopy images and EBSD orientation maps. A rotation toward the terminal stable [101] orientation was measured for the majority of specimens (with tensile axes more than ~17° from the [001] direction) at strain rates between $1.28 × 10^{-2}$ and 1000 s$^{-1}$.
id oai-inspirehep.net-1821682
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2020
record_format invenio
spelling oai-inspirehep.net-18216822020-10-09T20:00:45Zdoi:10.1016/j.msea.2020.140258http://cds.cern.ch/record/2740936engCroteau, J -FKulyadi, E PaiKale, CSiu, DKang, DFontenla, A T PerezValdivieso, E García-TabarésBieler, T REisenlohr, PSolanki, K NBalint, DHooper, P AAtieh, SJacques, NE CantergianiEffect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applicationsAccelerators and Storage RingsAn investigation of the mechanical properties of high-purity niobium single crystals is presented. Specimens were cut with different crystallographic orientations from a large grain niobium disk and uniaxial tensile tests were conducted at strain rates between 10$^{-4}$ and 10$^3$ s$^{-1}$. The logarithmic strain rate sensitivity for crystals oriented close to the center of a tensile axis inverse pole figure (IPF) is ~0.14 for all strain rates. The strain at failure (ranging from 0.4 to 0.9) is very sensitive to crystal orientation and maximal at $~10^{-2}$ s$^{-1}$ for crystals oriented close to the center of an IPF. The high anisotropy observed at quasi-static strain rates decreased with increasing strain rate. The activation of multiple slip systems in the dynamic tests could account for this reduction in anisotropy. A transition from strain hardening to softening in the plastic domain was observed at strain rates greater than approximately $6 × 10^{-2}$ s$^{-1}$ for crystals oriented close to the center of a tensile axis IPF. Shear bands were observed in specimens with orientations having similarly high Schmid factors on both and slip families, and they are correlated with reduced ductility. Crystal rotations at fracture are compared for the different orientations using scanning electron microscopy images and EBSD orientation maps. A rotation toward the terminal stable [101] orientation was measured for the majority of specimens (with tensile axes more than ~17° from the [001] direction) at strain rates between $1.28 × 10^{-2}$ and 1000 s$^{-1}$.oai:inspirehep.net:18216822020
spellingShingle Accelerators and Storage Rings
Croteau, J -F
Kulyadi, E Pai
Kale, C
Siu, D
Kang, D
Fontenla, A T Perez
Valdivieso, E García-Tabarés
Bieler, T R
Eisenlohr, P
Solanki, K N
Balint, D
Hooper, P A
Atieh, S
Jacques, N
E Cantergiani
Effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applications
title Effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applications
title_full Effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applications
title_fullStr Effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applications
title_full_unstemmed Effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applications
title_short Effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applications
title_sort effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for srf applications
topic Accelerators and Storage Rings
url https://dx.doi.org/10.1016/j.msea.2020.140258
http://cds.cern.ch/record/2740936
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