Glass Fatigue Crack (IMAGE) DOE/Lawrence Berkeley National Laboratory Caption Cracks propagate through metallic glass by following shear bands, which in this micrograph look like wrinkles in cloth. The featureless blobs in the picture are a second, crystalline phase of the metal, but if these barriers are not properly spaced to halt crack propagation, the metal can fail disastrously. Credit William Johnson, Caltech; Robert Ritchie, Berkeley Lab Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.