Interaction between Ni/Ti Nanomultilayers and Bulk Ti-6Al-4V during Heat Treatment
The diffusion bonding of Ti-6Al-4V to NiTi alloys assisted by Ni/Ti reactive multilayer thin films indicates the diffusion of Ni from the filler material towards bulk Ti-6Al-4V. As a consequence, the fragile NiTi<sub>2</sub> intermetallic phase is formed at the joint interface. In this c...
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| Format: | Article |
| Language: | English |
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MDPI AG
2018-10-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/8/11/878 |
| _version_ | 1828314536450457600 |
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| author | André João Cavaleiro Ana Sofia Ramos Francisco Braz Fernandes Carsten Baehtz Maria Teresa Vieira |
| author_facet | André João Cavaleiro Ana Sofia Ramos Francisco Braz Fernandes Carsten Baehtz Maria Teresa Vieira |
| author_sort | André João Cavaleiro |
| collection | DOAJ |
| description | The diffusion bonding of Ti-6Al-4V to NiTi alloys assisted by Ni/Ti reactive multilayer thin films indicates the diffusion of Ni from the filler material towards bulk Ti-6Al-4V. As a consequence, the fragile NiTi<sub>2</sub> intermetallic phase is formed at the joint interface. In this context, the aim of this work is to investigate the occurrence of Ni diffusion from Ni/Ti nanomultilayers towards Ti-6Al-4V substrates. For this purpose, multilayer coated Ti alloys were studied in situ at increasing temperatures using synchrotron radiation. After heat treatment, scanning electron microscopy (SEM) analyses were carried out and elemental map distributions were acquired by electron probe microanalysis (EPMA). The EPMA maps confirm the occurrence of Ni diffusion; the presence of Ni in the substrate regions immediately underneath the nanomultilayers is clearly indicated and becomes more pronounced as the temperature increases. The presence of Ni is observed in the same locations where V is found, thus in β-Ti grains of Ti-6Al-4V. At the same time, the synchrotron results together with SEM analyses allow the increase of the amount of β-Ti phase in Ti-6Al-4V to be identified, while the thin films are mainly constituted by NiTi<sub>2</sub>. Therefore, the presence of the brittle NiTi<sub>2</sub> intermetallic phase can be avoided if Ni diffusion is prevented. |
| first_indexed | 2024-04-13T16:46:23Z |
| format | Article |
| id | doaj.art-5a48e747f4fe436f9ea722c0e63f44e7 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-04-13T16:46:23Z |
| publishDate | 2018-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-5a48e747f4fe436f9ea722c0e63f44e72022-12-22T02:39:04ZengMDPI AGMetals2075-47012018-10-0181187810.3390/met8110878met8110878Interaction between Ni/Ti Nanomultilayers and Bulk Ti-6Al-4V during Heat TreatmentAndré João Cavaleiro0Ana Sofia Ramos1Francisco Braz Fernandes2Carsten Baehtz3Maria Teresa Vieira4CEMMPRE, Department of Mechanical Engineering, University of Coimbra, R. Luís Reis Santos, 3030-788 Coimbra, PortugalCEMMPRE, Department of Mechanical Engineering, University of Coimbra, R. Luís Reis Santos, 3030-788 Coimbra, PortugalCENIMAT/I3N, Department of Materials Science, Faculty of Sciences and Technology, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, PortugalHelmholtz Zentrum Dresden Rossendorf HZDR, Institute of Ion Beam Physics and Materials Research, D-01314 Dresden, GermanyCEMMPRE, Department of Mechanical Engineering, University of Coimbra, R. Luís Reis Santos, 3030-788 Coimbra, PortugalThe diffusion bonding of Ti-6Al-4V to NiTi alloys assisted by Ni/Ti reactive multilayer thin films indicates the diffusion of Ni from the filler material towards bulk Ti-6Al-4V. As a consequence, the fragile NiTi<sub>2</sub> intermetallic phase is formed at the joint interface. In this context, the aim of this work is to investigate the occurrence of Ni diffusion from Ni/Ti nanomultilayers towards Ti-6Al-4V substrates. For this purpose, multilayer coated Ti alloys were studied in situ at increasing temperatures using synchrotron radiation. After heat treatment, scanning electron microscopy (SEM) analyses were carried out and elemental map distributions were acquired by electron probe microanalysis (EPMA). The EPMA maps confirm the occurrence of Ni diffusion; the presence of Ni in the substrate regions immediately underneath the nanomultilayers is clearly indicated and becomes more pronounced as the temperature increases. The presence of Ni is observed in the same locations where V is found, thus in β-Ti grains of Ti-6Al-4V. At the same time, the synchrotron results together with SEM analyses allow the increase of the amount of β-Ti phase in Ti-6Al-4V to be identified, while the thin films are mainly constituted by NiTi<sub>2</sub>. Therefore, the presence of the brittle NiTi<sub>2</sub> intermetallic phase can be avoided if Ni diffusion is prevented.https://www.mdpi.com/2075-4701/8/11/878Ni/TimultilayersNiTi-6Al-4Vdiffusion |
| spellingShingle | André João Cavaleiro Ana Sofia Ramos Francisco Braz Fernandes Carsten Baehtz Maria Teresa Vieira Interaction between Ni/Ti Nanomultilayers and Bulk Ti-6Al-4V during Heat Treatment Metals Ni/Ti multilayers Ni Ti-6Al-4V diffusion |
| title | Interaction between Ni/Ti Nanomultilayers and Bulk Ti-6Al-4V during Heat Treatment |
| title_full | Interaction between Ni/Ti Nanomultilayers and Bulk Ti-6Al-4V during Heat Treatment |
| title_fullStr | Interaction between Ni/Ti Nanomultilayers and Bulk Ti-6Al-4V during Heat Treatment |
| title_full_unstemmed | Interaction between Ni/Ti Nanomultilayers and Bulk Ti-6Al-4V during Heat Treatment |
| title_short | Interaction between Ni/Ti Nanomultilayers and Bulk Ti-6Al-4V during Heat Treatment |
| title_sort | interaction between ni ti nanomultilayers and bulk ti 6al 4v during heat treatment |
| topic | Ni/Ti multilayers Ni Ti-6Al-4V diffusion |
| url | https://www.mdpi.com/2075-4701/8/11/878 |
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