Define "residual stress" in mechanical components.

Residual stress in mechanical components refers to the internal stresses that remain within a material even after the external forces or loads that initially caused those stresses have been removed. This phenomenon occurs as a result of various processes such as welding, machining, or cooling of materials. These stresses can significantly influence the mechanical behavior of components by affecting their strength, fatigue life, and potential for failure.

Understanding residual stress is crucial for material scientists and engineers because it can lead to distortion during machining or after manufacturing processes, and it can also impact the performance and longevity of mechanical components in service. Hence, recognizing that residual stress persists after the original causes are no longer present is essential for predicting how components will behave over time under operational conditions.