Extraordinary Response of H-Charged and H-Free Coherent Grain Boundaries in Nickel to Multiaxial Loading
The cohesive strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3, <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </sem...
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MDPI AG
2020-07-01
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| Series: | Crystals |
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| Online Access: | https://www.mdpi.com/2073-4352/10/7/590 |
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| author | Petr Šesták Miroslav Černý Zhiliang Zhang Jaroslav Pokluda |
| author_facet | Petr Šesták Miroslav Černý Zhiliang Zhang Jaroslav Pokluda |
| author_sort | Petr Šesták |
| collection | DOAJ |
| description | The cohesive strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3, <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>5, and <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>11 grain boundaries (GBs) in clean and hydrogen-segregated fcc nickel was systematically studied as a function of the superimposed transverse biaxial stresses using ab initio methods. The obtained results for H-free GBs revealed a quite different response of the coherent twinning boundary <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 to the applied transverse stresses in comparison to the other GB types. While the cohesive strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>5 and <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>11 GBs increased with increasing level of tensile transverse stresses, the strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 GB remained constant for any applied levels of transverse stresses. In the case of GBs with segregated hydrogen, the cohesive strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 was distinctly reduced for all levels of transverse stresses, while the strength reduction of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>5 and <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>11 GBs was significant only for a nearly isotropic (hydrostatic) triaxial loading. This extraordinary response explains a high susceptibility of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 GBs to crack initiation, as recently reported in an experimental study. Moreover, a highly triaxial stress at the fronts of microcracks initiated at <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 boundaries caused a strength reduction of adjacent high-energy grain boundaries which thus became preferential sites for further crack propagation. |
| first_indexed | 2024-03-10T18:36:30Z |
| format | Article |
| id | doaj.art-58664945c4384393b451693cbfb58b16 |
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| issn | 2073-4352 |
| language | English |
| last_indexed | 2024-03-10T18:36:30Z |
| publishDate | 2020-07-01 |
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| record_format | Article |
| series | Crystals |
| spelling | doaj.art-58664945c4384393b451693cbfb58b162023-11-20T06:13:11ZengMDPI AGCrystals2073-43522020-07-0110759010.3390/cryst10070590Extraordinary Response of H-Charged and H-Free Coherent Grain Boundaries in Nickel to Multiaxial LoadingPetr Šesták0Miroslav Černý1Zhiliang Zhang2Jaroslav Pokluda3Central European Institute of Technology, CEITEC BUT, Brno University of Technology, Purkyňova 123, CZ–612 00 Brno, Czech RepublicCentral European Institute of Technology, CEITEC BUT, Brno University of Technology, Purkyňova 123, CZ–612 00 Brno, Czech RepublicFaculty of Engineering, Norwegian University of Science and Technology (NTNU), Rich. Birkelandsvei 1A, 7491 Trondheim, NorwayCentral European Institute of Technology, CEITEC BUT, Brno University of Technology, Purkyňova 123, CZ–612 00 Brno, Czech RepublicThe cohesive strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3, <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>5, and <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>11 grain boundaries (GBs) in clean and hydrogen-segregated fcc nickel was systematically studied as a function of the superimposed transverse biaxial stresses using ab initio methods. The obtained results for H-free GBs revealed a quite different response of the coherent twinning boundary <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 to the applied transverse stresses in comparison to the other GB types. While the cohesive strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>5 and <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>11 GBs increased with increasing level of tensile transverse stresses, the strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 GB remained constant for any applied levels of transverse stresses. In the case of GBs with segregated hydrogen, the cohesive strength of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 was distinctly reduced for all levels of transverse stresses, while the strength reduction of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>5 and <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>11 GBs was significant only for a nearly isotropic (hydrostatic) triaxial loading. This extraordinary response explains a high susceptibility of <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 GBs to crack initiation, as recently reported in an experimental study. Moreover, a highly triaxial stress at the fronts of microcracks initiated at <inline-formula> <math display="inline"> <semantics> <mo>Σ</mo> </semantics> </math> </inline-formula>3 boundaries caused a strength reduction of adjacent high-energy grain boundaries which thus became preferential sites for further crack propagation.https://www.mdpi.com/2073-4352/10/7/590ab initio calculationshydrogen embrittlementgrain boundarycohesive strengthmultiaxial loading |
| spellingShingle | Petr Šesták Miroslav Černý Zhiliang Zhang Jaroslav Pokluda Extraordinary Response of H-Charged and H-Free Coherent Grain Boundaries in Nickel to Multiaxial Loading Crystals ab initio calculations hydrogen embrittlement grain boundary cohesive strength multiaxial loading |
| title | Extraordinary Response of H-Charged and H-Free Coherent Grain Boundaries in Nickel to Multiaxial Loading |
| title_full | Extraordinary Response of H-Charged and H-Free Coherent Grain Boundaries in Nickel to Multiaxial Loading |
| title_fullStr | Extraordinary Response of H-Charged and H-Free Coherent Grain Boundaries in Nickel to Multiaxial Loading |
| title_full_unstemmed | Extraordinary Response of H-Charged and H-Free Coherent Grain Boundaries in Nickel to Multiaxial Loading |
| title_short | Extraordinary Response of H-Charged and H-Free Coherent Grain Boundaries in Nickel to Multiaxial Loading |
| title_sort | extraordinary response of h charged and h free coherent grain boundaries in nickel to multiaxial loading |
| topic | ab initio calculations hydrogen embrittlement grain boundary cohesive strength multiaxial loading |
| url | https://www.mdpi.com/2073-4352/10/7/590 |
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