Enhanced grain refinement and texture weakening in Al–Mg–Si alloy through a novel thermomechanical processing

Abstract

A novel thermomechanical processing including solution treatment, first rolling with large deformation and overaging based on particle-stimulated nucleation of recrystallization (PSN) was proposed to obtain an Al–Mg–Si alloy sheet with fine grain structure, weak texture and high plastic strain ratio. The difference between conventional thermomechanical processing and novel thermomechanical processing with two overaging time parameters was investigated by texture and microstructure characterization and tensile tests. The results show that the finest grain structure with an average size of 17 µm, the weakest recrystallization texture with a volume fraction of 8.4 %, the highest average plastic strain ratio r of 0.69 and the lowest planar anisotropy Δr of − 0.001 were acquired by the novel thermomechanical processing with a long overaging time. In comparison with conventional thermomechanical processing, the novel thermomechanical processing can generate completely different particle distributions and tends to develop a weak texture consisting of the CubeND {001}<310>orientation. Increasing the overaging time is effective in coarsening the particles and thus refining the grain structure, weakening the texture, and improving the average r and Δr values. The genetic characteristics of texture evolution and the particle distribution determine the final recrystallization texture.