Abstract: 7B50 aluminum alloy containing microalloying element Zr was prepared in the laboratory and subjected to homogenization annealing and solution treatment. The low melting point phase, microstructure, mechanical properties and fracture morphology of the alloy were analyzed using metallographic microscopy, differential thermal analysis, X-ray diffraction analysis, electronic universal testing machine, scanning electron microscopy and transmission electron microscopy. The results show that the non-equilibrium solidification phase Mg(Al, Cu, Zn)₂ in the cast alloy can be eliminated by two-stage homogenization annealing at 420 ℃ for 3 h and 475 ℃ for 21 h, meantime the spherical Al₃Zr particles precipitated; thus, obtaining the best effect. The single stage solution treatment process is 480 ℃ insulation for 30 min to achieve the best comprehensive mechanical properties, with tensile strength of 574 MPa, yield strength of 535 MPa, and elongation of 13.3%.

Key words: 7B50 aluminum alloy, homogenizing annealing, solution treatment, mechanical properties