Elasto-viscoplastic tensile behavior of as-forged Ti-1023 alloy: Experiments and micromechanical modeling

This works focused on the mechanical behavior of an ‘as-forged’ Ti-1023 alloy used in airframe forging applications. Its microstructure, characterized by SEM and EBSD, was composed by 15% of primary αp nodules (2–5 μm in size) embedded in millimeter long β grains partially fragmented into equiaxed β subgrains of 5–10 μm. Further neutron diffraction analysis indicated an almost random β texture. Tensile tests at different strain rates were performed. A very low strain rate sensitivity was observed. The contribution of each phase to the overall mechanical behavior was numerically investigated by a two-phase elasto-viscoplastic self-consistent (EVPSC) model with affine-type linearization. Internal stresses arising from elastic and plastic strain incompatibilities were analyzed. Throughout the mechanical loading, {100}β oriented grains were more deformed than {111}β grains and all the α nodules. The onset of plasticity occurred sequentially in the β phase, initially in {110}β grains followed by {111}β and then {100}β ones. The effect of the crystallographic texture on slip activity was also studied through simulations made with a synthetic rotated cube β texture, typical of β-working, while considering α textures in Burgers Orientation Relationship (BOR) with the β phase or being random. © 2020 Elsevier B.V.