Final answer:
Ductile deformation involves gradual decrease in stress with increasing strain, while brittle deformation involves sudden drop in stress and minimal strain before fracture.
Step-by-step explanation:
The difference between ductile and brittle deformation in terms of stress and strain is as follows:
1. Ductile deformation occurs in materials that can undergo large plastic deformations before they fracture, such as metals. It is characterized by a gradual decrease in stress with increasing strain.
2. Brittle deformation occurs in materials that fracture easily with little or no plastic deformation, such as glass or ceramics. It is characterized by a sudden drop in stress and minimal strain before fracture.
So, ductile deformation is associated with materials that can undergo extensive plastic deformation before breaking, while brittle deformation is associated with materials that break without significant plastic deformation.
Example: Consider a piece of metal being stretched. As the metal is gradually deformed under stress, its stress-strain curve will show a decrease in stress as the metal becomes easier to deform. This is ductile deformation. In contrast, if a piece of glass is subjected to stress, it will show very minimal strain before suddenly fracturing, indicating brittle deformation.