INFLUENCE OF FCC ROLLING TEXTURES ON BIAXIAL SHEET STRETCHING

The behaviour of sheet metals initially having f.c.c. rolling textures is simulated under biaxial stretching conditions. A rate-sensitive crystal plasticity model together with the full-constraint Taylor theory is used. Closed-form analytical solutions for the stress states, slip distributions and lattice spins are obtained for the ideal orientations of fc.c. rolling textures, The three-dimensional lattice rotation fields at these ideal orientations, and their evolution paths in Euler space, are predicted for various biaxial stretching ratios. Similar simulations are also carried out for polycrystalline textures. It is shown that, for a copper-type initial texture (the beta-fibre) and a strain ratio rho < 0.5, the corresponding biaxial-stretching texture will not be much different from the initial texture. However, for rho > 0.5 the beta-fibre deteriorates and the alpha-fibre increases relatively quickly. If the initial texture is the R-recrystallization texture (cube + S1), the main component of the simulated biaxial-stretching textures is the fibre near beta for rho < 0.5, but the alpha-fibre for rho > 0.5. The simulated equibiaxial-stretching texture is in agreement with the published measured textures for aluminum sheets.