Étude cinétique et cristallographique de la précipitation de la phase alpha aux joints de grains bêta/bêta dans un alliage de titane

Abstract : This work focuses on the formation and the evolution of microstructure and microtexture associated with the [alpha] phase precipitation at [beta]/[beta] GBs in titanium alloys. A [beta]-metastable alloy (Ti17) has been studied, because the high temperature microstructure is frozen by a rapid quench and the untransformed parent phase remains. Numerous 2D EBSD analyses and some 3D analyses have been carried out after transformation and under various thermal and thermo-mechanical treatments (isothermal conditions and continuous cooling (CC) without and with prior deformation of the parent phase). One great originality of this study is the automated statistical approach used to characterize the microtexture from EBSD data. An algorithm has been specifically developed in order to get the variants orientation as well as different representative data characterizing the microtexture. We have identified the link between the nucleation/growth kinetics of [alpha] phase and the microtexture development, a relationship that is often neglected in the literature, where one usually associates the microtexture only to the variant selection and to the initial [beta] texture. The occurrence of variants selection (VS) has been performed considering different VS criteria; it has been shown that VS is very active for the first grains formed. These grains have the most favorable nucleation conditions. The variant selected is the one that minimizes the deviation to the Burgers Orientation Relationship with both [beta] grains; i.e. the one for which interfacial energy and especially the elastic energy associated to its formation are minimized. Moreover, the crystallographic conditions of [alpha] colonies formation are studied and discussed
Document type :
Theses
Complete list of metadatas

https://hal.univ-lorraine.fr/tel-01751571
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 1:21:52 PM
Last modification on : Tuesday, August 21, 2018 - 9:46:04 AM

File

DDOC_T_2015_0042_SALIB.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01751571, version 1

Citation

Matthieu Salib. Étude cinétique et cristallographique de la précipitation de la phase alpha aux joints de grains bêta/bêta dans un alliage de titane. Autre. Université de Lorraine, 2015. Français. ⟨NNT : 2015LORR0042⟩. ⟨tel-01751571⟩

Share

Metrics

Record views

36

Files downloads

120