Mechanical properties and microstructural evolution in Al–Cu–Mg–Ag alloy with a CuxMgx/10 content

In this study, we investigate the effect of CuxMgx/10 (x = 5.0, 5.5, 6.0, 6.8 wt.%) in Al–Cu–Mg-based alloys on the mechanical properties. Of these, the Cu6.0Mg0.60 alloy shows the highest mechanical properties of σUTS = 532 MPa (σy = 504 MPa) and ε = 11.1%. The amount of CuxMgx/10 solutes affects both macroscopic and microscopic microstructures of fabricated alloys. In the macroscopic observation, a higher content of CuxMgx/10 induces the grain size refinement and the formation of large particles in the grain boundaries. For the microscopic investigation using electron microscopies, the formation of θ′ strengthening phase is more accelerated by a higher content of CuxMgx/10 rather than the formation of Ω phase. Furthermore, microscopic structural distortion is significantly induced with a higher content of CuxMgx/10, which affects the tensile properties of the developed alloys.