What does the term 'metal fatigue' describe?

The term 'metal fatigue' specifically refers to the weakening of a material caused by the repeated application of stress or loads over time. This condition occurs when metal is subjected to cyclic loading, leading to the development of micro-cracks that can grow and eventually result in failure. It is a critical consideration in engineering and metal fabrication, as components that experience fluctuating forces—such as those found in vehicles, aircraft, and machinery—are particularly susceptible to this phenomenon.

Metals can endure a certain amount of stress without permanent deformation, but when they are subjected to these stresses repeatedly, even if each instance is below the material's ultimate tensile strength, it can lead to failure over time. Understanding metal fatigue is essential for ensuring safety and durability in design processes.

Other terms, like the loss of material due to corrosion or age-related deterioration, refer to different processes that affect the integrity of metals, while weight reduction over time does not accurately characterize any deterioration in metal properties but rather could be associated with physical changes that have no direct relation to fatigue.