slip plane

In physics and engineering, a slip plane is a plane within a crystal along which one part of the crystal can slide relative to another. This sliding displacement occurs under shearing forces, meaning forces acting parallel to the plane. Slip is a primary mechanism for the permanent, or plastic, deformation of materials.1

This deformation doesn't happen all at once. Instead, atoms move sequentially along the slip plane, facilitated by structural defects called edge dislocations. These dislocations move in the opposite direction, allowing for the gradual sliding of atomic rows. On a larger scale, slip involves many dislocations moving on nearby slip planes within multiple crystals, creating visible slip lines under magnification.1