A theoretical and experimental study is presented of texture evolution in hcp zirconium deformed at high temperatures. It is shown that, within the temperature range in which nuclear components are fabricated, the development of crystallographic texture is controlled by the simultaneous activation of $ langle$a$ rangle$ and $ langle$c + a$ rangle$ slip. This is demonstrated by experiments on Zr-2.5 Nb and unalloyed Zr deformed along three of the four elementary strain paths: axisymmetric elongation and compression and pure shear. Further experimental work on the axisymmetric deformation of unalloyed Zr and Zr-20 Nb shows that the influence of the bcc $ beta$-Zr phase present in Zr-2.5 Nb at the temperatures of interest is not due to the formation of crystallographic textures in this phase. / Texture evolution modelling was implemented for the case of polycrystalline hcp metals by making use of the duality principle between the generalized Taylor and Bishop-Hill theories of polycrystal plasticity and with the help of linear programming. The high temperature experimental textures for the three elementary strain paths mentioned above were successfully predicted using the relaxed constraint theory. It is shown that, for the cases of pure shear and compression, the so-called pancake version of this approach gives a better approximation to the observed textures than the full constraint calculations. For axisymmetric elongation, the curling version of the relaxed constraint model gives the best results. / By the analysis of slip activity maps, it is shown that the limitations of the full constraint model reside in the high activity level for $ langle$c + a$ rangle$ slip associated with this approach. When the relaxed constraint model is applied, the activity level of $ langle$c + a$ rangle$ slip is considerably reduced, leading to much better agreement of the predicted textures with the experimental results. The full constraint model is also applied to simulate texture evolution in $ alpha$-Zr deformed in simple shear at room temperature. It is demonstrated that the level of agreement is at least as good as that obtained when full constraint calculations were carried out. Finally, a high temperature texture rosette is proposed for prediction of the textures developed during tube forming operations for Zr alloy nuclear components. (Abstract shortened with permission of author.)
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75850 |
| Date | January 1988 |
| Creators | Salinas Rodríguez, Armando |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Mining and Metallurgical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000730899, proquestno: AAINL48552, Theses scanned by UMI/ProQuest. |
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