Effect of Hold Time Periods at High Temperature on Fatigue Life In Aluminum Alloy 2024 T4

Abstract

In some applications, the aluminum alloy 2024 T4 may be subjected to aninteraction of fatigue and creep effects at high temperature. This paper investigatesthe effect of this interaction by studying the effect of constant amplitude fatigue(CAF) and creep separately, and then fatigue-creep interaction is introduced bytesting the alloy under constant amplitude with some holding time periods throughthe test at high temperature (150 oC). The results showed that the life time of thealloy decreases due to fatigue-creep interaction as compared to creep alone inabout 77%, and in about 80% as compared with fatigue alone. This is a result ofaccumulated fatigue damage superimposed on creep damage. Creep allows morefree spaces for fatigue cracks paths that accelerate failure. A theoretical model tocalculate the time to failure due to fatigue-creep interaction has been proposed.This theoretical interaction model predicts very close time to failure values to theexperimental results.

Keywords

• fatigue
• creep interaction
• aluminum alloy
• constant amplitude interaction