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

Abstract

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%, andpeak 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.