Select a material to see how easy it is for the dislocation to move:

Copper

Peierls stress = 0.1 MPa

Iron

Peierls stress = 50 MPa

TiC

Peierls stress = 500 MPa

Diamond

Peierls stress = 34000 MPa

Applied Stress: 0 MPa

For a narrow dislocation...

For a wide dislocation...

The applied stress is less than the Peierls stress so the dislocation doesn't move

The applied stress is greater than the Peierls stress so the dislocation moves

A lower Peierls stress generally means it is easier for a dislocation to move through the material.

Materials with a higher Peierls stress will have smaller dislocation widths (narrow dislocations), since Δ U_p scales with w/b exponentially. Whereas materials with a lower Peierls stress will have wide dislocations. More info on narrow and wide dislocations can be found here -- dislocation width