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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2024
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2401.13818 |
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| _version_ | 1866911764447232000 |
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| author | Errandonea, Daniel Burakovsky, Leonid Preston, Dean L. MacLeod, Simon G. Santamaria-Perez, David Chen, Shaoping Cynn, Hyunchae Simak, Sergey I. McMahon, Malcolm I. Proctor, John E. Mezouar, Mohamed |
| author_facet | Errandonea, Daniel Burakovsky, Leonid Preston, Dean L. MacLeod, Simon G. Santamaria-Perez, David Chen, Shaoping Cynn, Hyunchae Simak, Sergey I. McMahon, Malcolm I. Proctor, John E. Mezouar, Mohamed |
| contents | Compared to other body-centered cubic (bcc) transition metals Nb has been the subject of fewer compression studies and there are still aspects of its phase diagram which are unclear. Here, we report a combined theoretical and experimental study of Nb under high pressure and temperature. We present the results of static laser-heated diamond anvil cell experiments up to 120 GPa using synchrotron-based fast x-ray diffraction combined with ab initio quantum molecular dynamics simulations. The melting curve of Nb is determined, and evidence for a solid-solid phase transformation in Nb with increasing temperature is found. The high-temperature phase of Nb is orthorhombic Pnma. The bcc-Pnma transition is clearly seen in the experimental data on the Nb principal Hugoniot. The bcc-Pnma coexistence observed in our experiments is explained. Agreement between the measured and calculated melting curves is very good except at 40-60 GPa where three experimental points lie below the theoretical melting curve by 250 K (or 7%); a possible explanation is given. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2401_13818 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Experimental and theoretical confirmation of an orthorhombic phase transition in niobium at high pressure and temperature Errandonea, Daniel Burakovsky, Leonid Preston, Dean L. MacLeod, Simon G. Santamaria-Perez, David Chen, Shaoping Cynn, Hyunchae Simak, Sergey I. McMahon, Malcolm I. Proctor, John E. Mezouar, Mohamed Materials Science Compared to other body-centered cubic (bcc) transition metals Nb has been the subject of fewer compression studies and there are still aspects of its phase diagram which are unclear. Here, we report a combined theoretical and experimental study of Nb under high pressure and temperature. We present the results of static laser-heated diamond anvil cell experiments up to 120 GPa using synchrotron-based fast x-ray diffraction combined with ab initio quantum molecular dynamics simulations. The melting curve of Nb is determined, and evidence for a solid-solid phase transformation in Nb with increasing temperature is found. The high-temperature phase of Nb is orthorhombic Pnma. The bcc-Pnma transition is clearly seen in the experimental data on the Nb principal Hugoniot. The bcc-Pnma coexistence observed in our experiments is explained. Agreement between the measured and calculated melting curves is very good except at 40-60 GPa where three experimental points lie below the theoretical melting curve by 250 K (or 7%); a possible explanation is given. |
| title | Experimental and theoretical confirmation of an orthorhombic phase transition in niobium at high pressure and temperature |
| topic | Materials Science |
| url | https://arxiv.org/abs/2401.13818 |