The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy
The influence of a keyhole defect on local deformation behaviour in additive manufactured Ti-6Al-4V was investigated by comparing it to a representative bulk region without a defect. High resolution digital image correlation (HRDIC) was used to measure the differences in strain localisation at the m...
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| Language: | English |
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Elsevier
2024-11-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785424027650 |
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| author | S. Cao R. Thomas A.D. Smith P. Zhang L. Meng H. Liu J. Guo J. Donoghue D. Lunt |
| author_facet | S. Cao R. Thomas A.D. Smith P. Zhang L. Meng H. Liu J. Guo J. Donoghue D. Lunt |
| author_sort | S. Cao |
| collection | DOAJ |
| description | The influence of a keyhole defect on local deformation behaviour in additive manufactured Ti-6Al-4V was investigated by comparing it to a representative bulk region without a defect. High resolution digital image correlation (HRDIC) was used to measure the differences in strain localisation at the microstructural length-scale. A nanoscale speckle pattern was used to allow small changes in strain to be detected and resolved within individual lamella and at pre-existing crack locations around the defect. Strain localisation was observed around the defect and formed well below the macroscopic yield stress. In contrast, minimal deformation was found in the bulk at this stress level. Following further deformation into the plastic regime, the strain localisation around the keyhole became more heterogenous with a distinct strain field. A large amount of strain localisation and <c+a> slip was observed either side of the defect normal to the loading direction compared to relatively little in the regions close to the defect in line with the loading direction. This HRDIC observation was consistent with finite element analysis of the expected strain fields around the defect both below and above the yield point. Furthermore, micro-cracks were observed in αp/αp and αp/βt interfaces in both regions with the more pronounced strain fields around the defect leading to an increased number of long micro-cracks than in the bulk. The formation mechanisms of micro-cracks have been discussed, emphasising the role of localised strain caused by the defect. |
| format | Article |
| id | doaj-art-de4a9e002bb94bed8bebd3b5fab6f2db |
| institution | Kabale University |
| issn | 2238-7854 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj-art-de4a9e002bb94bed8bebd3b5fab6f2db2024-12-26T08:56:04ZengElsevierJournal of Materials Research and Technology2238-78542024-11-013396649673The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloyS. Cao0R. Thomas1A.D. Smith2P. Zhang3L. Meng4H. Liu5J. Guo6J. Donoghue7D. Lunt8Institute of Advanced Wear & Corrosion Resistant and Functional Materials, National Joint Engineering Research Center of High Performance Metal Wear Resistant Materials Technology, Jinan University, Guangzhou, 510632, China; Department of Materials, The University of Manchester, Manchester, M13 9PL, UK; Department of Mechanical Engineering, College of Engineering, Shantou University, Shantou, 515063, China; Corresponding author. Institute of Advanced Wear & Corrosion Resistant and Functional Materials, National Joint Engineering Research Center of High Performance Metal Wear Resistant Materials Technology, Jinan University, Guangzhou 510632, China.Department of Materials, The University of Manchester, Manchester, M13 9PL, UKDepartment of Materials, The University of Manchester, Manchester, M13 9PL, UK; TESCAN-UK Ltd, Chestnut Court, Huntingdon, PE28 9ET, UKInstitute of Advanced Wear & Corrosion Resistant and Functional Materials, National Joint Engineering Research Center of High Performance Metal Wear Resistant Materials Technology, Jinan University, Guangzhou, 510632, ChinaDepartment of Mechanical Engineering, College of Engineering, Shantou University, Shantou, 515063, ChinaDepartment of Mechanical Engineering, College of Engineering, Shantou University, Shantou, 515063, ChinaDepartment of Mechanical Engineering, College of Engineering, Shantou University, Shantou, 515063, ChinaDepartment of Materials, The University of Manchester, Manchester, M13 9PL, UK; The Henry Royce Institute, Manchester, M13 9PL, UKDepartment of Materials, The University of Manchester, Manchester, M13 9PL, UK; United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK; Corresponding author. Department of Materials, The University of Manchester, Manchester, M13 9PL, UKThe influence of a keyhole defect on local deformation behaviour in additive manufactured Ti-6Al-4V was investigated by comparing it to a representative bulk region without a defect. High resolution digital image correlation (HRDIC) was used to measure the differences in strain localisation at the microstructural length-scale. A nanoscale speckle pattern was used to allow small changes in strain to be detected and resolved within individual lamella and at pre-existing crack locations around the defect. Strain localisation was observed around the defect and formed well below the macroscopic yield stress. In contrast, minimal deformation was found in the bulk at this stress level. Following further deformation into the plastic regime, the strain localisation around the keyhole became more heterogenous with a distinct strain field. A large amount of strain localisation and <c+a> slip was observed either side of the defect normal to the loading direction compared to relatively little in the regions close to the defect in line with the loading direction. This HRDIC observation was consistent with finite element analysis of the expected strain fields around the defect both below and above the yield point. Furthermore, micro-cracks were observed in αp/αp and αp/βt interfaces in both regions with the more pronounced strain fields around the defect leading to an increased number of long micro-cracks than in the bulk. The formation mechanisms of micro-cracks have been discussed, emphasising the role of localised strain caused by the defect.http://www.sciencedirect.com/science/article/pii/S2238785424027650Additive manufacturingTi-6Al-4VElectron backscattering diffraction (EBSD)High resolution digital image correlation (HRDIC)Strain localisationSlip trace analysis |
| spellingShingle | S. Cao R. Thomas A.D. Smith P. Zhang L. Meng H. Liu J. Guo J. Donoghue D. Lunt The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy Journal of Materials Research and Technology Additive manufacturing Ti-6Al-4V Electron backscattering diffraction (EBSD) High resolution digital image correlation (HRDIC) Strain localisation Slip trace analysis |
| title | The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy |
| title_full | The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy |
| title_fullStr | The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy |
| title_full_unstemmed | The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy |
| title_short | The effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy |
| title_sort | effect of a keyhole defect on strain localisation in an additive manufactured titanium alloy |
| topic | Additive manufacturing Ti-6Al-4V Electron backscattering diffraction (EBSD) High resolution digital image correlation (HRDIC) Strain localisation Slip trace analysis |
| url | http://www.sciencedirect.com/science/article/pii/S2238785424027650 |
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