Skip to Main content Skip to Navigation
Theses

3D short fatigue crack investigation in beta titanium alloys using phase and diffraction contrast tomography

Abstract : X-Ray Diffraction Contrast Tomography (DCT) is a recently developed, non-destructive synchrotron imaging technique which characterizes microstructure and grain orientation in polycrystalline materials in three dimensions (3D). By combining it with propagation based phase contrast tomography (PCT) it is for the first lime possible to observe in situ the 3D propagation behavior of short fatigue cracks (SFCs) within a set of fully characterized grains (orientation and shape). The combined approach, termed 3D X-ray Tomography of short cracks and Microstructure (3DXTSM), has been developed on the metastable beta titanium alloy "Beta21S". A large part of this work deals with the development of the 3DXTSM methodology. In the combined dataset, each point on the 3D fracture surface can be associated with a multidimensional data structure containing variables describing the grain orientation, the local fracture surface normal and the propagation history. The method uses a surface mesh composed of triangles that describes the crack (in other words: the fracture surface) in the last propagation state measured. Grain orientations, crack fronts, local growth rates and grain boundaries can be visualized by assigning colors to this mesh. The data structure can be interrogated in a number of different ways. Tools for extracting pole figures and pole density distribution functions have been implemented. An algorithm was developed that is capable of measuring the 3D local growth rate of a crack containing branches. The accuracy of the grain boundaries as reconstructed with OCT was evaluated and the elastic constants of Beta21S were determined.
Document type :
Theses
Complete list of metadatas

Cited literature [141 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00690521
Contributor : Abes Star :  Contact
Submitted on : Monday, April 23, 2012 - 5:37:33 PM
Last modification on : Wednesday, September 16, 2020 - 3:51:22 AM
Long-term archiving on: : Tuesday, July 24, 2012 - 2:35:26 AM

File

these.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-00690521, version 1

Citation

Michael Herbig. 3D short fatigue crack investigation in beta titanium alloys using phase and diffraction contrast tomography. Other. INSA de Lyon, 2011. English. ⟨NNT : 2011ISAL0010⟩. ⟨tel-00690521⟩

Share

Metrics

Record views

493

Files downloads

1394