On the Correlation Between Fatigue Striation Spacing and Crack Growth Rate: A Three-Dimensional (3-D) X-ray Synchrotron Tomography Study

In situ three-dimensional (3-D) X-ray synchrotron tomography of fatigue crack growth was conducted in a 7075-T6 aluminum alloy. Local measurements of da/dN were possible with the 3-D data sets obtained from tomography. A comparison with fatigue striation spacings obtained from scanning electron microscopy of the fracture surfaces yielded excellent correlation with da/dN obtained from tomography. The X-ray tomography technique can be used to obtain a highly accurate and representative measurements of crack growth locally in the microstructure of the material.