Structure and Properties of New Wrought Al–Cu–Y- and Al–Cu–Er-Based Alloys

The structure and properties of new wrought aluminum Al–4.5Cu–1.6Y–0.9Mg–0.6Mn–0.2Zr–0.1Ti–0.15Fe–0.15Si and Al–4.0Cu–2.7Er–0.8Mg–0.8Mn–0.2Zr–0.1Ti–0.15Fe–0.15Si alloys are studied. After homogenization and rolling, the structure is formed, which consists of the aluminum-based solid solution strengthened with fine Al₃(Zr,Er), Al₃(Zr,Y), and Al₂₀Cu₂Mn₃ phase particles and compact thermally stable phases of solidification origin 1–5 µm in size. The recrystallization after rolling occurs at temperatures above 350°С. As the annealing temperature increases from 400 to 550°С, the recrystallized grain size increases from 6–8 to 10–12 µm. At temperatures of 150–180°С, the hardness increases after 2-h annealing; this is related to the occurrence of aging, and the analogous effect was observed for the cast alloys of these systems. The yield strength of the Y-containing alloy subjected to 6-h annealing at 150°С is 405 MPa; in this case, the relative elongation is 4.5%. As the annealing temperature increases to 210°С, the yield strength of the both alloys decreases to 300 MPa, whereas the relative elongation remains unchanged. In the case of the alloys quenched after rolling and subsequently aged at 210°С, the yield strength of 264–266 MPa and ultimate tensile strength of 356–365 MPa are reached at a relative elongation of 11.3–14.5%. As a result, the new wrought Al–Cu–Y- and Al–Cu–Er-based alloys provide competition for the available industrial alloys.