Kink bands promote exceptional fracture resistance in a NbTaTiHf refractory medium-entropy alloy
Single-phase body-centered cubic (bcc) refractory medium- or high-entropy alloys can retain compressive strength at elevated temperatures but suffer from extremely low tensile ductility and fracture toughness. We examined the strength and fracture toughness of a bcc refractory alloy, NbTaTiHf, from 77 to 1473 kelvin. This alloy's behavior differed from that of comparable systems by having fracture toughness over 253 MPa·m1/2, which we attribute to a dynamic competition between screw and edge dislocations in controlling the plasticity at a crack tip. Whereas the glide and intersection of screw and mixed dislocations promotes strain hardening controlling uniform deformation, the coordinated slip of <111> edge dislocations with {110} and {112} glide planes prolongs nonuniform strain through formation of kink bands. These bands suppress strain hardening by reorienting microscale bands of the crystal along directions of higher resolved shear stress and continually nucleate to accommodate localized strain and distribute damage away from a crack tip.
| Medienart: |
E-Artikel |
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| Erscheinungsjahr: |
2024 |
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| Erschienen: |
2024 |
| Enthalten in: |
Zur Gesamtaufnahme - volume:384 |
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| Enthalten in: |
Science (New York, N.Y.) - 384(2024), 6692 vom: 12. Apr., Seite 178-184 |
| Sprache: |
Englisch |
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| Beteiligte Personen: |
Cook, David H [VerfasserIn] |
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| Links: |
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| Anmerkungen: |
Date Revised 11.04.2024 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
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| doi: |
10.1126/science.adn2428 |
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| funding: |
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| PPN (Katalog-ID): |
NLM370928326 |
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| 245 | 1 | 0 | |a Kink bands promote exceptional fracture resistance in a NbTaTiHf refractory medium-entropy alloy |
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| 500 | |a Date Revised 11.04.2024 | ||
| 500 | |a published: Print-Electronic | ||
| 500 | |a Citation Status PubMed-not-MEDLINE | ||
| 520 | |a Single-phase body-centered cubic (bcc) refractory medium- or high-entropy alloys can retain compressive strength at elevated temperatures but suffer from extremely low tensile ductility and fracture toughness. We examined the strength and fracture toughness of a bcc refractory alloy, NbTaTiHf, from 77 to 1473 kelvin. This alloy's behavior differed from that of comparable systems by having fracture toughness over 253 MPa·m1/2, which we attribute to a dynamic competition between screw and edge dislocations in controlling the plasticity at a crack tip. Whereas the glide and intersection of screw and mixed dislocations promotes strain hardening controlling uniform deformation, the coordinated slip of <111> edge dislocations with {110} and {112} glide planes prolongs nonuniform strain through formation of kink bands. These bands suppress strain hardening by reorienting microscale bands of the crystal along directions of higher resolved shear stress and continually nucleate to accommodate localized strain and distribute damage away from a crack tip | ||
| 650 | 4 | |a Journal Article | |
| 700 | 1 | |a Kumar, Punit |e verfasserin |4 aut | |
| 700 | 1 | |a Payne, Madelyn I |e verfasserin |4 aut | |
| 700 | 1 | |a Belcher, Calvin H |e verfasserin |4 aut | |
| 700 | 1 | |a Borges, Pedro |e verfasserin |4 aut | |
| 700 | 1 | |a Wang, Wenqing |e verfasserin |4 aut | |
| 700 | 1 | |a Walsh, Flynn |e verfasserin |4 aut | |
| 700 | 1 | |a Li, Zehao |e verfasserin |4 aut | |
| 700 | 1 | |a Devaraj, Arun |e verfasserin |4 aut | |
| 700 | 1 | |a Zhang, Mingwei |e verfasserin |4 aut | |
| 700 | 1 | |a Asta, Mark |e verfasserin |4 aut | |
| 700 | 1 | |a Minor, Andrew M |e verfasserin |4 aut | |
| 700 | 1 | |a Lavernia, Enrique J |e verfasserin |4 aut | |
| 700 | 1 | |a Apelian, Diran |e verfasserin |4 aut | |
| 700 | 1 | |a Ritchie, Robert O |e verfasserin |4 aut | |
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