Fatigue Variable Loading Under Combined High Temperature and Shot Peening Treatment for AA2024-T4 and AA2024-T361

The variable fatigue loading (VL) is an important issue for aircraft safety. Indeed, aluminium alloy parts are always the subject of this type of thermo-mechanical alterations. This study examined the effect (VL) under normal operating conditions. We investigated the effect of fatigue variable loading (VL) under combined high temperature (HT) and shot peening (SP) treatment for (AA2024-T4 and AA2024-T361). Fatigue under loading from 250 to 350MPa with various combinations of loading cycles is presented.

The experimental fatigue life results were compared to Miner’s rule. The comparison shows that the fatigue life of tested specimens during the low to high stress sequences is higher than that of the (high to low) ones. This highlights the beneficial effect of (SP) which made the fatigue life predicted by Miner rule safe but not economical. We conclude that considered alloys under SP improves the variable fatigue life under 250°C. In fact, taking into account the interaction effects of loading sequences, those due to high temperature and surface treatment such as (SP) is very important for fatigue prediction based on such alloys.