Superplasticity in Fine Grain Ti-6Al-4V Alloy: Mechanical Behavior and Microstructural Evolution

Laurie Despax (1) , Vanessa Vidal (1) , Denis Delagnes (1) , Moukrane Dehmas (2) , Morgane Geyer (1) , Hiroaki Matsumoto (3) , Vincent Velay (1)

1 ICA - Institut Clément Ader
2 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux
3 Kagawa University

Titanium Ti-6Al-4V alloys are known to exhibit interesting superplastic properties for different conditions of temperature and strain rate, depending on the initial grain size. Even if superplasticity is generally explained in terms of grain boundary sliding (GBS) accompanied by several accommodation mechanisms, it appears that the micromechanisms of superplasticity are still controversial especially at the grain scale and even more at lower scale. These micromechanisms, involving microstructural evolution, depend also on the SPF conditions (temperature, strain rate and initial microstructure). In this study, the flow stress in the Ti-6Al-4V alloy is investigated for different strain rate and for temperature in the range of the α/β transformation. The preferred orientation evolution of alpha phase grains for different percentage of deformation is studied for a non-optimal SPF regime (920°C-10-4 s-1) in order to highlight the microstructural evolution and so the deformation mechanisms involved. For that, mechanical interrupted test combined with Scanning Electron Microscopy (SEM) and Electron Back Scatter Diffraction (EBSD) are used.

Mots clés: Superplasticity; Texture; Ti-6Al-4V; Titanium Alloy; Titanium alloys; Mechanical behavior; β-phase proportion

Domaines: Matériaux; Mécanique des solides [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Laurie Despax, Vanessa Vidal, Denis Delagnes, Moukrane Dehmas, Morgane Geyer, et al.. Superplasticity in Fine Grain Ti-6Al-4V Alloy: Mechanical Behavior and Microstructural Evolution. ICSAM 2018 - 13th International Conference on Superplasticity in Advanced Materials, Aug 2018, St Pertersbourg, Russia. pp.137-143, ⟨10.4028/www.scientific.net/DDF.385.137⟩. ⟨hal-01864428⟩