I. screw dislocation ① only slip ②2p⊥l 3pane:l× E B (4 dislocation motion VS. crystal movement Macroscopic deformation =-6 Ad- area over which dislocation swept A5-area of slip plane or climb plane◆ Ⅱ.Screw dislocation ① only slip. ② ③ plane: ④ dislocation motion vs. crystal movement. Macroscopic deformation = Ad —— area over which dislocation swept. As —— area of slip plane or climb plane. v l   ⊥ l v    b A A s d b      v 