Question

a) What are edge and screw dislocations and why are they important in metals?;

b-) Make a 2D sketch of an edge dislocation using the ball and stick model of the crystalline state and show its salient features such as extra-half plane, dislocation core, state of stress above and below the slip plane, and Burger’s vector. What does the Burgers vector designate?;

(c-) Why does dislocation slip take place on closed packed crystallographic planes and along close packed crystallographic directions? Why is screw dislocation slip easier than edge dislocation slip in metals? Why dislocation motion (slip) is not possible at room temperature in ionic solids such as NaCl?

Answer 1