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Overview Processing and Characterizing Titanium AlloysThe prediction of microstructure during processing needs to characterize the phase transformation occurring during the thermal treatments and their kinetics. In-situ high-energy synchrotron x-ray diffraction experiments performed during temperature variations allow the characterization of the phase evolution. For some transformation conditions, the continuous recording of diffraction diagrams evidences clearly intermediate phases. The quantitative analysis of the diffraction diagrams gives the transformation kinetics of each phase as well as their cell parameters. Transformation kinetics obtained by this method are

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To cite this version:Julien da Costa Teixeira, Benoît Appolaire, Elisabeth Aeby-Gautier, Sabine Denis, Fabien Bruneseaux. Modeling of the effect of the beta phase deformation on the alpha phase precipitation in near-beta titanium alloys. Acta Materialia, Elsevier, 2006, 54, pp. AbstractA model has been developed in order to describe the influence of a prior plastic deformation of the β phase above the transus on the precipitation of the α phase occurring during a subsequent cooling. The model relies on the calculation of the nucleation and growth rates of the α precipitates at the grain boundaries, based on a model presented formerly. Two major modifications have been carried out: first, the geometrical representation of the β microstructure accounts for subgrains resulting from the deformation process; second, the calculation of the nucleation rate is dependent on the conditions of the plastic deformation. A careful analysis of the main parameters of the model has led to distinguish between several assumptions: the Widmanstätten colonies are likely to cross the subgrains during their growth; and the critical width of the transition from the allotriomorphs to the Widmanstätten plates is likely to decrease when the misorientation angle of the grain boundary decreases. Calculations performed for assessing the influence of the strain and strain rate on the transformation kinetics are in good agreement with previous measurements.