Phase transformations, strength and fracture toughness of the beta-metastable alloy Ti-5553
(2012)
Files
PhDThesis.pdf
Restricted Access - Adobe PDF
- 43.5 MB
Details
- Authors
- Supervisors
- Jacques, Pascal
- Abstract
- (en) A great interest has recently been given to titanium alloys due to their wide range of applications in medical, automotive and especially aerospace industries. For some applications, titanium alloys are key materials with their high performance to density ratio, allowing weight reduction while keeping the same mechanical resistance. Furthermore, the β-metastable alloys start to replace other α and α + β alloys since they present higher levels of specific strength. This work focuses on the Ti-5553 alloy, a promising alloy intended to replace other titanium alloys such as the Ti-10V-2Fe-3Al alloy or some steels for structural airframe applications. However, the fracture toughness of the Ti-5553 alloy reduces its range of applications. To improve the properties of the alloy, the damage and fracture mechanisms have to be completely understood. Based on this characterization, the microstructural weaknesses of the alloy can be improved by controlling the phase transformations. This work follows this logic : some phase transformations are investigated in order to control the microstructures. The transformation domain of the ω phase has been determined thanks to a resistivity measurement and the influence of the α precipitates on the mechanical behavior has been highlighted. Besides this microstructural analysis, a characterization of the damage and fracture mechanisms has been carried out thanks to tensile tests with various stress triaxiality conditions and to the measurement of the crack propagation resistance of several microstructures. The final aim of the thesis was to identify the microstructural weaknesses and to generate an improved microstructure with a better combination of strength and fracture toughness.
- Affiliations
Citations
Dufour, P. (2012). Phase transformations, strength and fracture toughness of the beta-metastable alloy Ti-5553. https://hdl.handle.net/2078.5/160345