回転曲げ疲労条件下における複数き裂の進展・干渉挙動の放射光μCTを用いた評価

概要

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Fatigue crack propagation behavior is essential to investigate the mechanism of fatigue fracture. The replication technique has been used to observe the behavior on the surface of various materials; however, the technique does not provide the information on the shape of cracks inside materials. In the present study, the authors have attempted micro computed tomography (μCT) with synchrotron radiation of SPring-8 to observe the cracks inside the specimens. Cracks were introduced through rotating-bending fatigue loading on aircraft aluminum alloy A7050-T7451 specimens. The crack images were intermittently visualized by μCT during the propagation. The interference and coalescence of the two fatigue cracks were evaluated, which were closely located in a plane or parallel planes perpendicular to the axis of each specimen. Fatigue crack propagation rates were calculated using the pairs of crack images with different fatigue cycles. Stress intensity factors were estimated by the Pariss law with the calculated crack propagation rate, which revealed that the high points in stress intensity factor corresponded with those by other researchers for the axial loading of plate specimens.
日本材料学会の論文