Effects of thermomechanical processing on production of Al-Zn-Mg-Cu alloy plate

An Al-7.81Zn-1.81Mg-1.62Cu alloy was subjected to a kind of thermomechanical processing involving solution annealing, quenching, pre-precipitation and warm rolling, with the aim of finding a new efficient way to prevent recrystallization in Al-Zn-Mg-Cu (7XXX) series alloys. On the basis of information on the microstructures from optical metallography (OM) and transmission electron microscopy (TEM), and on the textures from orientation distribution functions (ODFs), we learn that during subsequent solution treatment, appropriate nano/submicron-scale MgZn2 particles, which are precipitated in the thermomechanical processing, inhibit the migration of grain/sub-grain boundaries, and do not induce particle stimulated nucleation (PSN), thus leading to a remarkable decrease in the recrystallized fraction. Suitable thermomechanical processing produced an ultimate tensile strength of 528 MPa and yield strength of 459 MPa, as well as good intergranular corrosion (IGC) resistance.