Week 2 Flashcards
What is meant by the term plastic deformation?
Plastic deformation refers to irreversible deformation or change in shape that occurs
when the force or stress that caused it is removed.
Do amorphous and crystalline materials plastically deform by the same mechanisms?
Explain.
No. Amorphous materials do not have a periodic arrangement of ions and hence do not
contain dislocations. Plastic deformation in amorphous materials is due to sliding of
atoms over one another due to applied stress. This mechanism is called as viscous flow
mechanism.
In crystalline materials, plastic deformation is due to the process of crystalline slip that
results from the motion of dislocations.
What are the imperfections in the atomic arrangements that have a significant effect on
the material behaviour?
The imperfections in the atomic arrangements only represent defects in or deviations
from the perfect or ideal atomic or ionic arrangements expected in a given structure.
The material is not considered defective from a technological viewpoint. In many
applications, the presence of such defects is useful. Often the defects may be created
intentionally to produce a desired set of electronic, magnetic, optical, or mechanical
properties.
What is meant by the term elastic deformation?
Elastic deformation is a temporary change in shape that occurs while a force or stress
remains applied to a material.
