Edge dislocation slide presentation

1. PRESENTED BY :
1) ALI SAN IMAM PAVEL ( 1613014)
2) MAHAMUD HASAN TUSHER (1613028)
3) MINHAZ UDDIN (1613026)
Edge Dislocation

2. What is Dislocations
 A dislocation is a line that separates the slipped and unsliped part in a
crystal
 Dislocation is a crystallographic defect or irregularity within a crystal
structure.
ations

3. Types
 Edge dislocation
A portion of extra half plane of atoms
 Screw Dislocation
Helical atomic displacement around a line extending through the crystal

4. Types of Edge Dislocation
1.Positive Edge Dislocation:
The extra half plane is above the slip plane of the crystal and this
dislocation is called positive edge dislocation and is denoted by
Inverse T.
2.Negative Edge dislocation:
The extra half plane is below the slip plane of the crystal and it is
called negative edge dislocation and is denoted by T

5. Dislocation in Motion

7.  BURGERS VECTOR : In material
science , the magnitude and the
direction of the displacement are
defined by a vector is called Burgers
vector. It is denoted by b . The Burgers
vector of a dislocation is an important
property of a dislocation because , if
the Burgers vector and the orientation
line are known, the dislocation is
completely described .
Burgers vector and burgers circuit

8. For a pure edge dislocation the Burgers vector is perpendicular to the dislocation line, while for
a pure screw dislocation the Burgers vector is parallel to the dislocation line. Actually,
dislocations in real crystals are rarely straight lines and rarely lie in a single plane

10. A convenient way of defining the Burgers vector of a dislocation is by means of the
Burgers circuit.
Starting at a lattice point , imagine a path traced from atom to atom , an equal
distance in each direction , always in the direction of one of the vectors of unit cell. If
the region enclosed by the path does not contain a dislocation , the burgers circuit will
close. However, if the path encloses a dislocation , the burgers circuit will not closed .
The closure failure of the burgers circuit is the bergers vector.
BERGERS CIRCUIT

20.  Slip explains the strength of metals is much lower than the value
predicted from the metallic bond.
 Slip provides ductility in metals.
 To control the mechanical properties of a metal or alloy by interfering with
the movement of dislocations.
 Influence electronic and optical properties of materials.
Significance of Edge Dislocation