9 = 0.6 I / s ' 7 = 6.0 0 7 = 2 4 i ti 3 = 6 0 Through close control over green-state powder processing, pure alumina ceramics of 0.5-pm grain size were obtained by sintering at 1250°C. The static grain growth of this material was modest at temperatures below 1300°C. However, dynamic grain growth occurred rapidly during superplastic deformation. Therefore, although the ultrafine-grained alumina...

Based on the dominated deformation mechanisms of superplastic materials, an assumption for micro-damage evolution is presented. Then, a set of uni®ed viscoplastic-damage constitutive equations is proposed to model material hardening due to the increase of dislocation density and grain growth, as well as material softening due to intergranular void nucleation and growth. The effects of the harde...

Abstract. The presentation will illustrate the creation and production ramp-up of Titanium Hot Forming Superplastic Technology in a French aeronautical supplier from Industrialization to A320NEO full-rate production. With deformation elongations well beyond classical « cold » sheet metal forming capabilities (especially with high-strength titanium alloys such as Ti64 refractory Ti6242), were ke...

High temperature plastic flow properties of two phase TiAl alloys containing 45 to 49 at.%Al have been investigated in thermo-mechanically grain refined materials in order to clarify the favourable microstructure and chemical composition for TiAl based superplastic materials. Grain sizes of thermomechanical treated materials and their grain size stability during subsequent high temperature defo...

We examine the e€ect of 10 vol.% TiB whisker reinforcement on transformation superplasticity of Ti±6Al±4V, induced by thermal cycling about the a/b phase transformation range of the matrix under a uniaxial tensile stress. During superplastic deformation, the whiskers gradually align along the external loading axis, as measured by electron back-scattering diffraction of deformed specimens. The c...