The Structure and Properties of Sheets of the Al-Zn-Mg-Cu-Zr-Y(Er) Alloy Doped with Manganese

The structure and properties of rolled Al-Zn-Mg-Cu-Zr-Y(Er) alloys doped with manganese and modified with titanium have been studied. According to the results of tensile testing in the deformed state after annealings at 120-150 degrees C for 1 h, the AlZnMgCuMnTi and AlZnMgCuMnTiEr alloys show a high yield strength of 417-456 MPa with a small relative elongation of 2-5.2%. The presence of additional dispersion-forming elements, such as yttrium and erbium, increases the density of particles precipitated in the course of homogenization annealing due to increase in the recrystallization onset temperature and in the hardness of the rolled alloys. After 1 h annealing at 350 degrees C, the AlZnMgCuMnTi alloy has a completely recrystallized structure, while the alloys doped with yttrium and erbium only start to recrystallize. After quenching from the heated state at 465 degrees C and aging at 120 degrees C, the test alloys have a yield strength of more than 410 MPa, a tensile strength of more than 520 MPa, and an elongation of more than 10%. The obtained parameters are higher than the parameters of clad sheets of the high-strength heat-hardened Al-Zn-Mg-Cu (B95A) alloy and rods of the AlZn4.5Mg1.5Mn and AlZnMg1.5Mn alloys, and are comparable to the characteristic levels of rods of the Al-Zn-Mg-Cu (B95) alloy.