The Effect of Termomechanical Treatment on the Low-Cyclic Fatigue Behavior in an Al–Cu–Mg–Ag Alloy

The mechanical behavior under monotonic and cyclic loadings has been studied in an Al–4.5Cu–0.56Mg–0.77Ag–0.42Mn–0.12Ti–0.05V–0.02Fe (wt %) alloy subjected to thermomechanical treatment (TMT), including a solution heat treatment, quenching in water, uniaxial tension with a plastic strain of 3%, and peak aging at 190°C (state T83 according to the classification of the Aluminum Association). The T83‑ed alloy demonstrates the lowest tensile strength properties in comparison with T6 state (traditional aging) and TMT, including rolling with a 40%-reduction (T840). Compared to T6 and T840 states, the lowest cyclic strength and cyclic strain hardening coefficients in the Ramberg-Osgood relationship was found to be in T83-ed alloy. To achieve long fatigue life, it is advisable to reduce to the minimum values the degree of intermediate plastic deformation required for straightening Al–Cu–Mg–Ag sheets after their buckling during high-temperature heating for quenching.