What are jogs and kinks?

What are jogs and kinks?

Jogs and kinks are atomic scale changes in direction of a dislocation line. Jogs are out of the slip plane and kinks lie in the dislocations slip plane. For both jogs and kinks the Burgers vector and line vector are those of the dislocation, the line vector being along the direction of the jog or the kink.

What kind of deformation does the motion of dislocations produce?

Dislocation motion leads to plastic deformation. extra 1/2-plane exits. motion is called slip (movement of dislocations). The extra 1/2-plane moves along the slip plane.

What are the two types of dislocations?

Dislocations are generated and move when a stress is applied. The motion of dislocations allows slip-plastic deformation to occur. There are two types of dislocations: edge and screw. High dislocation density results in a large number of dislocation interactions, which results in high strength and hardness.

What causes the movement of dislocations?

Dislocations can move if the atoms from one of the surrounding planes break their bonds and rebond with the atoms at the terminating edge. In effect, a half plane of atoms is moved in response to shear stress by breaking and reforming a line of bonds, one (or a few) at a time.

What is kink motion?

Kink movement Kinks facilitate the movement of dislocations along its glide plane under shear stress, and is directly responsible for plastic deformation of crystals. Kink movement is strongly dependent on temperature as well.

What are kinks meaning?

1 : a short tight twist or curl caused by a doubling or winding of something upon itself. 2a : a mental or physical peculiarity : eccentricity, quirk. b : whim.

What are the features of dislocations in metals?

Dislocations are defined as the irregularities in the structure of metals. These arise from misplacement of bonds of the atoms in a part of the plane of a crystal and are considered to be weak centres. They are instrumental in affecting the breaking stress and plastic and chemical properties of crystals.

What is the role of dislocations in deformation of metals?

Dislocations play an essential role in the plastic deformations of crystalline materials. They prevent the synchronized breakage of bonds between atoms in materials and cause gradual deformation by making the one-by-one breakage of single bonds possible.

What are the different types of dislocations?

Common joint dislocations: shoulder, elbow, knee, hip, finger, collarbone, jaw, wrist, ankle and foot

• Shoulder dislocation.
• Elbow dislocation.
• Kneecap (patellar) dislocation.
• Knee joint dislocation.
• Hip dislocation.
• Dislocated finger.
• Dislocated jaw joint.
• Wrist dislocation.

Can dislocations move across grain boundaries?

Abstract. – Dislocations interact with grain boundaries during yielding, creep, and recrystallization. It will be assumed that the dislocation model for grain boundary structure is valid gene- rally. Consequently, Burgers vectors are conserved and dislocation lines can end only on other dislocations or free surfaces.

Why is the movement of dislocations compared to Caterpillar?

Dislocation motion is analogous to movement of a caterpillar. The caterpillar would have to exert a large force to move its entire body at once. Instead it moves the rear portion of its body forward a small amount and creates a hump.

What are kinks dislocation?

Kinks are deviations of a dislocation defect along its glide plane. In edge dislocations, the constant glide plane allows short regions of the dislocation to turn, converting into screw dislocations and producing kinks.

How are jogs and Kinks formed in a dislocation?

An edge dislocation with Burgers vector b2 cuts through an edge dislocation with Burgers vector b1, which lies in the plane perpendicular to the plane of the moving dislocation. Kinks are formed when the jogs resulted froma dislocation intersection lie in the slip plane instead of normal to it.

What is the difference between a kink and a jog?

Jogs and kinks are atomic scale changes in direction of a dislocation line. Jogs are out of the slip plane and kinks lie in the dislocations slip plane. For the edge dislocation shown, the jogs are of opposite sign (direction) and the region between the jogs has moved up from the original slip plane by one atomic spacing.

Why do jogs in edge dislocations move?

Jogs in edge dislocations are obviously prime places for the emission or absorption of point defects as is shown in the next illustration which looks at the inserted half-plane of an edge dislocation. The movement of jogs by emission or absorption of point defects means that the dislocation moves.

How many Jog does a screw dislocation produce?

The intersection of the edge dislocation with the screw dislocation produces one jog each per dislocation. (Consider the cut-and-move procedure and you will see why).