"What Really Sank the Titanic: New Forensic Discoveries Solve One of History's Deadliest Mysteries"
by Jennifer Hooper McCarty and Tim Foecke
A scanning electron microscope image of broken wrought iron, pulled along the direction of the fibers. The size slag you would like to have for good mechanical properties is like the piece at center-left. The one in the middle is much too big, but was not nearly as large as the biggest ones we found.