Final answer:
The increase in the flow stress resulting from plastic deformation is referred to as work hardening. This process makes the material harder and stronger due to the interaction of dislocations during deformation, which increases the material's yield strength and resistance to further deformation.
Step-by-step explanation:
The increase in the flow stress resulting from plastic deformation is usually referred to as work hardening or strain hardening. Work hardening occurs when a ductile material, such as metal, is plastically deformed, which means it has been shaped beyond its elastic limit and will not return to its original form once the external force is removed. As the material is deformed, dislocations within the material's crystal structure interact and multiply, making further deformation more difficult. This results in an increase in the yield strength of the material, as it becomes harder and stronger.<\/p>
Plastic deformation refers to the permanent change in shape due to the application of a stress beyond the material's elastic limit, at which point it will not recover its shape even when the stress is removed. The key microscopic mechanisms responsible for plasticity include dislocation motion, twin formation, and phase transformations among others. These mechanisms vary depending on the material being deformed.<\/p>
Ductile materials, which include most metals, actually become tougher and more resistant to further deformation as a result of work hardening. This increased resistance to deformation is quantitatively expressed by a higher flow stress in the material.<\/p>