Influence of out-of-plane stretch forming induced different strain paths on micro-texture evolution, slip system activity and Taylor factor distribution in Al–Li alloy

Abstract

A detailed investigation on the microstructure and micro-texture evolution in Al–Li alloy has been carried out following deformation at various strain paths. The stretch forming tests have been conducted to achieve three distinct strain paths, viz. close to uniaxial, plane strain and equi-biaxial. A correlation has been established between the microstructural and micro-textural developments with the various strain paths. The development of Brass {110}<112> and Cube {001}<100> components during uniaxial deformation and evolution of Goss component {110}<001> with development of <011>//ND fiber during equi-biaxial deformation have been observed as stable orientations. Meanwhile, a marginal strengthening of R {214}<112> and S component {123}<634> is noticed during plane strain deformation. The deformation micro-texture and associated active number of slip systems under different deformation modes are simulated using visco-plastic self-consistent (VPSC) polycrystalline model. During uniaxial deformation, the availability of the least number of active slip systems leads to the development of a relatively stronger micro-texture. Moreover, a detailed insight into the Taylor factor has been performed to elucidate its distribution based on the micro-textural developments along the three deformation paths. The higher fraction of grains in Taylor factor range M ∼ 2–3 during uniaxial and plane strain deformation is associated with the presence of Cube component {001}<100>. On the contrary, the higher fraction of grains in Taylor factor range M ∼ 3–4 during equi-biaxial deformation is related to the strengthening of <011>//ND fiber. The fewer number of grains in Taylor factor range M ∼ 4–5, as observed during plane strain deformation, is attributed to the evolution of Brass texture {110}<112>.