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Crystal Structure Defects in Titanium Nickelide after Abc Pressing at Lowered Temperature
The experimental results regarding the effect of warm (573 K) abc pressing with an increase in the specified true strain, e, up to 9.55, on the microstructure and crystal structure defects (dislocations, vacancies) of the Ti(49.8)Ni(50.2) (at %) alloy are presented. It is shown that all samples (reg...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9227948/ https://www.ncbi.nlm.nih.gov/pubmed/35744353 http://dx.doi.org/10.3390/ma15124298 |
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author | Lotkov, Aleksandr Grishkov, Victor Laptev, Roman Mironov, Yuri Zhapova, Dorzhima Girsova, Natalia Gusarenko, Angelina Barmina, Elena Kashina, Olga |
author_facet | Lotkov, Aleksandr Grishkov, Victor Laptev, Roman Mironov, Yuri Zhapova, Dorzhima Girsova, Natalia Gusarenko, Angelina Barmina, Elena Kashina, Olga |
author_sort | Lotkov, Aleksandr |
collection | PubMed |
description | The experimental results regarding the effect of warm (573 K) abc pressing with an increase in the specified true strain, e, up to 9.55, on the microstructure and crystal structure defects (dislocations, vacancies) of the Ti(49.8)Ni(50.2) (at %) alloy are presented. It is shown that all samples (regardless of e) have a two-level microstructure. The grains–subgrains of the submicrocrystalline scale level are in the volumes of large grains. The average sizes of both large grains and subgrain grains decrease with increasing e to 9.55 (from 27 to 12 µm and from 0.36 to 0.13 µm, respectively). All samples had a two-phase state (rhombohedral R and monoclinic B19′ martensitic phases) at 295 K. The full-profile analysis of X-ray reflections of the B2 phase obtained at 393 K shows that the dislocation density increases from 10(14) m(−2) to 10(15) m(−2) after pressing with e = 1.84 and reaches 2·10(15) m(−2) when e increases to 9.55. It has been established by positron annihilation lifetime spectroscopy that dislocations are the main type of defects in initial samples and the only type of defects in samples after abc pressing. The lifetime of positrons trapped by dislocations is 166 ps, and the intensity of this component increases from 83% in the initial samples to 99.4% after pressing with e = 9.55. The initial samples contain a component with a positron lifetime of 192 ps (intensity 16.4%), which corresponds to the presence of monovacancies in the nickel sublattice of the B2 phase (concentration ≈10(−5)). This component is absent in the positron lifetime spectra in the samples after pressing. The results of the analysis of the Doppler broadening spectroscopy correlate with the data obtained by the positron annihilation lifetime spectroscopy. |
format | Online Article Text |
id | pubmed-9227948 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-92279482022-06-25 Crystal Structure Defects in Titanium Nickelide after Abc Pressing at Lowered Temperature Lotkov, Aleksandr Grishkov, Victor Laptev, Roman Mironov, Yuri Zhapova, Dorzhima Girsova, Natalia Gusarenko, Angelina Barmina, Elena Kashina, Olga Materials (Basel) Article The experimental results regarding the effect of warm (573 K) abc pressing with an increase in the specified true strain, e, up to 9.55, on the microstructure and crystal structure defects (dislocations, vacancies) of the Ti(49.8)Ni(50.2) (at %) alloy are presented. It is shown that all samples (regardless of e) have a two-level microstructure. The grains–subgrains of the submicrocrystalline scale level are in the volumes of large grains. The average sizes of both large grains and subgrain grains decrease with increasing e to 9.55 (from 27 to 12 µm and from 0.36 to 0.13 µm, respectively). All samples had a two-phase state (rhombohedral R and monoclinic B19′ martensitic phases) at 295 K. The full-profile analysis of X-ray reflections of the B2 phase obtained at 393 K shows that the dislocation density increases from 10(14) m(−2) to 10(15) m(−2) after pressing with e = 1.84 and reaches 2·10(15) m(−2) when e increases to 9.55. It has been established by positron annihilation lifetime spectroscopy that dislocations are the main type of defects in initial samples and the only type of defects in samples after abc pressing. The lifetime of positrons trapped by dislocations is 166 ps, and the intensity of this component increases from 83% in the initial samples to 99.4% after pressing with e = 9.55. The initial samples contain a component with a positron lifetime of 192 ps (intensity 16.4%), which corresponds to the presence of monovacancies in the nickel sublattice of the B2 phase (concentration ≈10(−5)). This component is absent in the positron lifetime spectra in the samples after pressing. The results of the analysis of the Doppler broadening spectroscopy correlate with the data obtained by the positron annihilation lifetime spectroscopy. MDPI 2022-06-17 /pmc/articles/PMC9227948/ /pubmed/35744353 http://dx.doi.org/10.3390/ma15124298 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Lotkov, Aleksandr Grishkov, Victor Laptev, Roman Mironov, Yuri Zhapova, Dorzhima Girsova, Natalia Gusarenko, Angelina Barmina, Elena Kashina, Olga Crystal Structure Defects in Titanium Nickelide after Abc Pressing at Lowered Temperature |
title | Crystal Structure Defects in Titanium Nickelide after Abc Pressing at Lowered Temperature |
title_full | Crystal Structure Defects in Titanium Nickelide after Abc Pressing at Lowered Temperature |
title_fullStr | Crystal Structure Defects in Titanium Nickelide after Abc Pressing at Lowered Temperature |
title_full_unstemmed | Crystal Structure Defects in Titanium Nickelide after Abc Pressing at Lowered Temperature |
title_short | Crystal Structure Defects in Titanium Nickelide after Abc Pressing at Lowered Temperature |
title_sort | crystal structure defects in titanium nickelide after abc pressing at lowered temperature |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9227948/ https://www.ncbi.nlm.nih.gov/pubmed/35744353 http://dx.doi.org/10.3390/ma15124298 |
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