Analysis of Cold Dwell Fatigue Crack Initiation Site in a β-Forged Ti-6242 Disk in Relation with Local Texture
The α and prior β textures and microtextures of a lamellar Ti6242 forged disk were characterized by advanced electron back scattered diffraction (EBSD) and related to crystallographic features of faceted crack initiation sites of dwell fatigue specimens tested along the radial direction (RD). Large...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-07-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/10/7/951 |
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| author | Lionel Germain Youssef Samih Pierre Delaleau Joseph Gilgert Nathalie Gey |
| author_facet | Lionel Germain Youssef Samih Pierre Delaleau Joseph Gilgert Nathalie Gey |
| author_sort | Lionel Germain |
| collection | DOAJ |
| description | The α and prior β textures and microtextures of a lamellar Ti6242 forged disk were characterized by advanced electron back scattered diffraction (EBSD) and related to crystallographic features of faceted crack initiation sites of dwell fatigue specimens tested along the radial direction (RD). Large feather-like structures of α colonies with close orientations were observed at boundaries of elongated prior β grains. Their orientation belongs to the <11-20>α//z fiber, aligning the c-axis in RDs (z: axial direction of the disk). They are inherited from prior β grains belonging to the major <100>β and minor <111>β//z fibers. These feather-like structures are strong regions of the forging that act as a preferential crack initiation site. Adjacent to them, one can observe large colony with evidence of prismatic slip. Thus, the facet formation seems triggered by stress redistribution from “weak” to “strong” regions due to the elastic and plastic anisotropy. Finally, the occurrence of neighboring β grains able to share close oriented feather-like colonies is discussed considering the reconstructed β microtexture and texture. This study may be helpful for further texture control during the forging process. |
| first_indexed | 2024-03-10T18:28:52Z |
| format | Article |
| id | doaj.art-9d303bb973c14ea095e716c61552ba2b |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-10T18:28:52Z |
| publishDate | 2020-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-9d303bb973c14ea095e716c61552ba2b2023-11-20T06:47:54ZengMDPI AGMetals2075-47012020-07-0110795110.3390/met10070951Analysis of Cold Dwell Fatigue Crack Initiation Site in a β-Forged Ti-6242 Disk in Relation with Local TextureLionel Germain0Youssef Samih1Pierre Delaleau2Joseph Gilgert3Nathalie Gey4LEM3, Université de Lorraine, CNRS, Arts et Métiers ParisTech, F-57000 Metz, FranceLEM3, Université de Lorraine, CNRS, Arts et Métiers ParisTech, F-57000 Metz, FranceSAFRAN Aircraft Engines, Site de Gennevilliers, 92700 Colombes, FranceLEM3, Université de Lorraine, CNRS, Arts et Métiers ParisTech, F-57000 Metz, FranceLEM3, Université de Lorraine, CNRS, Arts et Métiers ParisTech, F-57000 Metz, FranceThe α and prior β textures and microtextures of a lamellar Ti6242 forged disk were characterized by advanced electron back scattered diffraction (EBSD) and related to crystallographic features of faceted crack initiation sites of dwell fatigue specimens tested along the radial direction (RD). Large feather-like structures of α colonies with close orientations were observed at boundaries of elongated prior β grains. Their orientation belongs to the <11-20>α//z fiber, aligning the c-axis in RDs (z: axial direction of the disk). They are inherited from prior β grains belonging to the major <100>β and minor <111>β//z fibers. These feather-like structures are strong regions of the forging that act as a preferential crack initiation site. Adjacent to them, one can observe large colony with evidence of prismatic slip. Thus, the facet formation seems triggered by stress redistribution from “weak” to “strong” regions due to the elastic and plastic anisotropy. Finally, the occurrence of neighboring β grains able to share close oriented feather-like colonies is discussed considering the reconstructed β microtexture and texture. This study may be helpful for further texture control during the forging process.https://www.mdpi.com/2075-4701/10/7/951fatiguefractographytitanium alloysbimodal microstructureEBSD |
| spellingShingle | Lionel Germain Youssef Samih Pierre Delaleau Joseph Gilgert Nathalie Gey Analysis of Cold Dwell Fatigue Crack Initiation Site in a β-Forged Ti-6242 Disk in Relation with Local Texture Metals fatigue fractography titanium alloys bimodal microstructure EBSD |
| title | Analysis of Cold Dwell Fatigue Crack Initiation Site in a β-Forged Ti-6242 Disk in Relation with Local Texture |
| title_full | Analysis of Cold Dwell Fatigue Crack Initiation Site in a β-Forged Ti-6242 Disk in Relation with Local Texture |
| title_fullStr | Analysis of Cold Dwell Fatigue Crack Initiation Site in a β-Forged Ti-6242 Disk in Relation with Local Texture |
| title_full_unstemmed | Analysis of Cold Dwell Fatigue Crack Initiation Site in a β-Forged Ti-6242 Disk in Relation with Local Texture |
| title_short | Analysis of Cold Dwell Fatigue Crack Initiation Site in a β-Forged Ti-6242 Disk in Relation with Local Texture |
| title_sort | analysis of cold dwell fatigue crack initiation site in a β forged ti 6242 disk in relation with local texture |
| topic | fatigue fractography titanium alloys bimodal microstructure EBSD |
| url | https://www.mdpi.com/2075-4701/10/7/951 |
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