Crystal Defects

Step 1: Understanding the Concept:
An edge dislocation is a linear crystal defect where an extra half-plane of atoms is introduced into the lattice. The dislocation line is the edge of this half-plane. The Burgers vector describes the magnitude and direction of the lattice distortion.
Step 2: Detailed Explanation:
Statement A: The slip caused by the movement of an edge dislocation is in the direction of the Burgers vector. The dislocation line itself moves on the slip plane in response to a shear stress, and its direction of motion is parallel to the Burgers vector. Therefore, this statement is correct.
Statement B: The definition of an edge dislocation is the insertion of an extra half-plane (or row) of atoms. This statement correctly describes the physical nature of an edge dislocation. So, statement B is correct.
Statement C: The extra half-plane of atoms terminates within the crystal. The line along which it terminates is the dislocation line, which is internal to the crystal. So, statement C is correct.
Statement D: For an edge dislocation, the Burgers vector ( ) is perpendicular ( ) to the dislocation line ( ). The Burgers vector is parallel to the dislocation line only for a screw dislocation. So, statement D is incorrect.
Step 3: Final Answer:
The correct statements are A, B, and C.