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Abstract In this study, one of the severe plastic deformation (SPD) techniques, Equal Channel Angular Pressing (ECAP) has been successfully applied to the Al-Cu-Li alloy AA2195 at 250 °C and the development of microstructure, texture and mechanical properties has been studied. A systematic analysis has been carried out by using EBSD and TEM to understand the microstructural features, and the nature of different precipitates presence in the alloy AA2195. Microstructural features indicate considerable grain refinement leading to an average grain size of 2.8 ± 0.7 μm after 4 ECAP passes. Continuous dynamic recrystallization (CDRX) has been identified as the mechanism that leads to the formation of fine grain structure in the alloy AA2195 during the warm ECAP process. TEM results confirm the distribution of strengthening precipitates δ′(Al 3 Li), β(Al 3 Zr) and T 1 (Al 2 CuLi) in the alloy. The overall texture has become weak after ECAP processing and has been simulated using Visco-plastic self-consistent simulation (VPSC). The evaluation of mechanical properties indicates a substantial increment in hardness, strength properties with a minor reduction of ductility after 4 passes. Low mechanical property anisotropy is expected in the processed AA2195 alloy due to its weak texture. Highlights • Significant grain refinement is achieved in AA2195 alloy after four ECAP passes. • Continuous dynamic recrystallization occurs during ECAP processing at 250 °C. • ECAP leads to overall weakening of texture. • Improvement in strength is achieved after ECAP. [ABSTRACT FROM AUTHOR]

Al-Cu-Li alloy (AA2195) was produced using vacuum induction melting (VIM) furnace under dynamic argon atmosphere. The as-cast billets were homogenized using a two-step homogenization cycle. The hot deformation behavior of homogenized and forged AA2195 alloy was studied by hot isothermal compression in a thermo-mechanical simulator. The contour maps of efficiency of power dissipation and instability maps have been generated within the temperature range of 250–450 °C and strain rate range of 10 −3 –10 2 s −1 . Various deformation mechanisms, which operate in different temperature–strain rate regimes, were identified with the aid of these maps and complementary microstructural analysis of the deformed specimens was carried out. Results indicate four distinct deformation domains within the range of experimental conditions examined. Out of these four domains, the optimum temperature and strain rate range for obtaining a completely reconstituted microstructure is T: 400 °C-450 °C and ε ˙ : 10 −2 -10 −1.5 s −1 and ε ˙ : 10 −0.5 -10 1 s −1 . Instability mechanisms in the material are attributed to localized plastic flow and cracking. A constitutive equation that describes the flow stress of AA2195 alloy as a function of strain rate and deformation temperature was also established. [ABSTRACT FROM AUTHOR]

In the present work, anisotropy in stress relaxation aging (SRA) behavior and yield strength of AA2195 alloy has been investigated in solution heat treatment (ST), pre-deformation after solution heat treatment (PS),and artificial aging after pre-deformation (APS). It is found that the three different pre-treatments methods have significant effects on the anisotropic behavior of SRA, and the in planar anisotropy (IPA) value of the total relaxed stress from small to large is APS < PS < ST. We find that the T 1 phase hinders the anisotropy of relaxed stress, and the earlier and the faster the T 1 phase precipitates, the greater the hindering effect. Under the ST and PS pre-treatments, the yield strength anisotropy decreased after SRA, from 13.8% and 13.2% to 8.9% and 7.5%, the difference between the two pre-treatments may be due to the dislocation produced during PS pre-treatment promoting the precipitation of T 1 phase. Under the APS pre-treatment, the yield strength anisotropy increases from 6.2% to 6.5% after SRA, indicating that the T 1 phase produced by APS pre-treatment plays a role in reducing the yield strength anisotropy. The different pre-treatments lead to different initial structure states, which should be responsible for the difference in the anisotropy of SRA behavior, as is the yield strength. • • The different anisotropy in SRA behavior under differ ent pre-treatments is related to the T 1 phase. • The different pre-treatments lead to different initial structure states, causing the different anisotropy in SRA behavior. [ABSTRACT FROM AUTHOR]