Slip plane is the crystallographic plane along which the dislocation line traverses.

• A. The plane with maximum atomic density
• B. The plane perpendicular to the dislocation line
• C. The crystallographic plane along which the dislocation line traverses
• D. The plane parallel to the surface

Answer: (C)

Dislocations glide along a specific crystallographic plane, and that plane is the one in which the dislocation line lies as it moves. This plane, the slip plane, provides the path of least resistance for atomic rearrangements during plastic deformation, so the dislocation traverses within it while the Burgers vector lies along a direction also contained in that plane. That’s why the statement that the slip plane is the crystallographic plane along which the dislocation line traverses is the correct description.

Other planes don’t define slip simply by being oriented a certain way: a plane perpendicular to the dislocation line wouldn’t be the glide path, and a plane parallel to the surface is not a crystallographic selection. Planes with high atomic density often host glide because they offer easier movement, but the fundamental idea is that the slip plane is the plane that the dislocation line travels along.