Influence of changes in structural and mechanical condition of aluminum alloys caused by impact-oscillatory loading on their fatigue life

Abstract

New experimental data on the influence of changes in the structural and mechanical condition of aluminum alloys D16ChATW and 2024-T3 due to impact-oscillatory loading on a wide-range variation of their fatigue life are presented. The dynamic deformation of the alloys in the process of realization of dynamic non-equilibrium processes (DNP) due to impact-oscillatory loading εimp was chosen as a parameter that characterizes the intensity of introduction of impulse energy into the alloys. It has been shown for the first time that the structural and mechanical condition of the alloys changes gradually as a result of an increase in the εimp value in the alloys during the realization of DNP. This manifests itself in the formation of yielding areas of different lengths under subsequent static stretching. The optimum intensities of introducing force impulse energy into aluminum alloys are found, which ensure a guaranteed extension of their fatigue life in comparison with the initial state. The approximate test frequency was 110 Hz. The comparison of experimental results with previously obtained data on the effect of impact-oscillatory loading on fatigue life of similar alloys at load frequencies of 15 Hz indicates a significant difference in the reaction of alloys D16ChATW and 2024-T3 to an increase in loading frequency.