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Microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy
CONTEXT: Recent introduction of shape memory (SM) nickel-titanium (NiTi) alloy into endodontics is a major breakthrough. Although the flexibility of these instruments was enhanced, fracture of rotary endodontic instruments during instrumentation is an important challenge for the operator. Implementa...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Medknow Publications & Media Pvt Ltd
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4502124/ https://www.ncbi.nlm.nih.gov/pubmed/26180413 http://dx.doi.org/10.4103/0972-0707.159727 |
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author | Vinothkumar, Thilla Sekar Kandaswamy, Deivanayagam Prabhakaran, Gopalakrishnan Rajadurai, Arunachalam |
author_facet | Vinothkumar, Thilla Sekar Kandaswamy, Deivanayagam Prabhakaran, Gopalakrishnan Rajadurai, Arunachalam |
author_sort | Vinothkumar, Thilla Sekar |
collection | PubMed |
description | CONTEXT: Recent introduction of shape memory (SM) nickel-titanium (NiTi) alloy into endodontics is a major breakthrough. Although the flexibility of these instruments was enhanced, fracture of rotary endodontic instruments during instrumentation is an important challenge for the operator. Implementation of supplementary manufacturing methods that would improve the fatigue life of the instrument is desirable. AIM: The purpose of this study was to investigate the role of dry cryogenic treatment (CT) conditions on the microstructure of martensitic SM NiTi alloy. MATERIALS AND METHODS: Experiments were conducted on Ni-51 wt% Ti-49 wt% SM alloy. Five cylindrical specimens and five sheet specimens were subjected to different CT conditions: Deep CT (DCT) 24 group: −185°C; 24 h, DCT 6 group: −185°C; 6 h, shallow CT (SCT) 24 group: −80°C, 24 h, SCT 6 group: −80°C, 6 h and control group. Microstructure of surface was observed on cylindrical specimens with an optical microscope and scanning electron microscope at different magnifications. Subsurface structure was analyzed on sheet specimens using X-ray diffraction (XRD). RESULTS: Microstructures of all SM NiTi specimens had equiaxed grains (approximately 25 μm) with well-defined boundaries and precipitates. XRD patterns of cryogenically treated specimens revealed accentuation of austenite and martensite peaks. The volume of martensite and its crystallite size was relatively more in DCT 24 specimen. CONCLUSIONS: DCT with 24 h soaking period increases the martensite content of the SM NiTi alloy without altering the grain size. |
format | Online Article Text |
id | pubmed-4502124 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Medknow Publications & Media Pvt Ltd |
record_format | MEDLINE/PubMed |
spelling | pubmed-45021242015-07-15 Microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy Vinothkumar, Thilla Sekar Kandaswamy, Deivanayagam Prabhakaran, Gopalakrishnan Rajadurai, Arunachalam J Conserv Dent Original Article CONTEXT: Recent introduction of shape memory (SM) nickel-titanium (NiTi) alloy into endodontics is a major breakthrough. Although the flexibility of these instruments was enhanced, fracture of rotary endodontic instruments during instrumentation is an important challenge for the operator. Implementation of supplementary manufacturing methods that would improve the fatigue life of the instrument is desirable. AIM: The purpose of this study was to investigate the role of dry cryogenic treatment (CT) conditions on the microstructure of martensitic SM NiTi alloy. MATERIALS AND METHODS: Experiments were conducted on Ni-51 wt% Ti-49 wt% SM alloy. Five cylindrical specimens and five sheet specimens were subjected to different CT conditions: Deep CT (DCT) 24 group: −185°C; 24 h, DCT 6 group: −185°C; 6 h, shallow CT (SCT) 24 group: −80°C, 24 h, SCT 6 group: −80°C, 6 h and control group. Microstructure of surface was observed on cylindrical specimens with an optical microscope and scanning electron microscope at different magnifications. Subsurface structure was analyzed on sheet specimens using X-ray diffraction (XRD). RESULTS: Microstructures of all SM NiTi specimens had equiaxed grains (approximately 25 μm) with well-defined boundaries and precipitates. XRD patterns of cryogenically treated specimens revealed accentuation of austenite and martensite peaks. The volume of martensite and its crystallite size was relatively more in DCT 24 specimen. CONCLUSIONS: DCT with 24 h soaking period increases the martensite content of the SM NiTi alloy without altering the grain size. Medknow Publications & Media Pvt Ltd 2015 /pmc/articles/PMC4502124/ /pubmed/26180413 http://dx.doi.org/10.4103/0972-0707.159727 Text en Copyright: © Journal of Conservative Dentistry http://creativecommons.org/licenses/by-nc-sa/3.0 This is an open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Article Vinothkumar, Thilla Sekar Kandaswamy, Deivanayagam Prabhakaran, Gopalakrishnan Rajadurai, Arunachalam Microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy |
title | Microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy |
title_full | Microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy |
title_fullStr | Microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy |
title_full_unstemmed | Microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy |
title_short | Microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy |
title_sort | microstructure of cryogenically treated martensitic shape memory nickel-titanium alloy |
topic | Original Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4502124/ https://www.ncbi.nlm.nih.gov/pubmed/26180413 http://dx.doi.org/10.4103/0972-0707.159727 |
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