Where does plastic deformation typically occur?

Plastic deformation in the form of slip occurs along the close-packed lattice planes, where the energy requirement for dislocation motion is minimized. Slip inside a crystal progresses until the dislocation line reaches the end of the crystal, where it results in a visible step – a so called slip band.

What are the types of plastic deformation processes?

Deformation processes can be conveniently classified into bulk-forming processes (e.g., rolling, extrusion, and forging) and sheet-forming processes (e.g., stretching, flanging, drawing, and contouring).

Which mechanism explains the plastic deformation of metals?

Slip is the prominent mechanism of plastic deformation in metals. It involves sliding of blocks of crystal over one other along definite crystallographic planes, called slip planes.

How do you know when deformation becomes plastic?

For stresses beyond the elastic limit, a material exhibits plastic behavior. This means the material deforms irreversibly and does not return to its original shape and size, even when the load is removed. When stress is gradually increased beyond the elastic limit, the material undergoes plastic deformation.

What is happening in material during plastic deformation?

Plastic deformation is the permanent distortion that occurs when a material is subjected to tensile, compressive, bending, or torsion stresses that exceed its yield strength and cause it to elongate, compress, buckle, bend, or twist.

Why does plastic deformation occur in the lower crust?

At the Earth’s surface, rocks usually break quite quickly, but deeper in the crust, where temperatures and pressures are higher, rocks are more likely to deform plastically. Sudden stress, such as a hit with a hammer, is more likely to make a rock break. Stress applied over time often leads to plastic deformation.

Why does plastic deformation lead to work hardening?

Work hardening, also known as strain hardening, is the strengthening of a metal or polymer by plastic deformation. This strengthening occurs because of dislocation movements and dislocation generation within the crystal structure of the material.

What is plastic deformation mechanism?

Plastic deformation is a process in which the size and shape of the object changed due to external load or forces. Plastic deformation is a permanent deformation which does not change after removal of external load or forces. Plastic deformation is an irreversible process of deformation.

What is the microscopic explanation for plastic deformation of a metal?

When the stress is sufficient to permanently deform the metal, it is called plastic deformation. As discussed in the section on crystal defects, plastic deformation involves the breaking of a limited number of atomic bonds by the movement of dislocations.

Which material does not exhibit a plastic region during tension?

Brittle materials such as concrete or carbon fiber do not have a well-defined yield point, and do not strain-harden. Therefore, the ultimate strength and breaking strength are the same. Typical brittle materials like glass do not show any plastic deformation but fail while the deformation is elastic.

What does plastic deformation depend on?

Generally, plastic deformation is also dependent on the deformation speed, i.e. higher stresses usually have to be applied to increase the rate of deformation. Such materials are said to deform visco-plastically.

Why does plastic deformation occur in the lower crust quizlet?

At the Earth’s surface, rocks usually break quite quickly, but deeper in the crust, where temperatures and pressures are higher, rocks are more likely to deform plastically. Sudden stress such as a hit with a hammer, is more likely to make a rock break. Stress applied over time often leads to plastic deformation.