Raquel Rodriguez-Lamas

When you pull on a piece of metal, it changes shape and simultaneously becomes stronger. The secret lies in tiny defects in the crystal lattice called dislocations. They are like wrinkles in a rug: moving a wrinkle shifts the rug more easily than dragging the whole rug.

An X-ray beam can peer inside an opaque piece of metal and show where cracks or stresses are hiding. But to see such defects, the beam must be focused into a very narrow pencil, just as sunlight is focused by a magnifying glass into a hot spot. In an X-ray microscope, the lens plays the role of the magnifying glass.