알루미늄 합금재의 미소원공결함이 피로크랙 전파거동에 미치는 영향

The Influence of the fatigue Crack Propagation Behavior on the Small Circular hole Defect in Aluminum Alloys

We carried out with materials of aluminum alloy(7075-T6, 2024-T4) by rotary bending fatigue tester. We investigated fatigue limit, fatigue crack initiation, fatigue crack propagation behavior and possibility of fatigue life prediction to the different small circular hole defect. The summarized result are as follows ; Fatigue limit of the smooth specimens were related tensile strength and yield strength. In case of more large applied stress and small circular hole crack defect, the fatigue crack was grown rapidly. The fatigue crack propagation behavior proceed at according to inclusion. Fatigue crack propagation ration appeared instability and retardation phenomenon in the first half of fatigue life but appeared stability and replied in the latter half. We are think on account of size of the small circular hole defect. On other hand, this experimental data of the materials are appeared fatigue life predictability.