What term describes the process by which materials break down after being subjected to repeated stress or strain?

The term that describes the process by which materials break down after being subjected to repeated stress or strain is fatigue. Fatigue occurs when a material is exposed to fluctuating loads over time, leading to the initiation and growth of cracks within the material, ultimately resulting in failure. This phenomenon is crucial in fields like engineering and materials science, as it emphasizes the importance of understanding the limits of material performance under cyclic loading conditions.

Creep refers to the gradual deformation of a material under constant stress over time, particularly at elevated temperatures. Fracture denotes the separation of a material into pieces due to stress exceeding its strength. Yielding is the point at which a material begins to deform plastically and cannot return to its original shape. These concepts, while related to material behavior under stress, do not specifically describe the process of breakage due to repeated loading.