MM504 Lecture 28: Cyclic softening and hardening

Cyclic hardening and softening refer to the changes in material properties, specifically its hardness or strength, after undergoing repeated cycles of loading and unloading. Cyclic hardening occurs when the material becomes stronger and harder with each cycle, while cyclic softening is the opposite, where the material becomes weaker and softer with each cycle. These phenomena are commonly observed in metals and alloys subjected to repeated loading and unloading, such as in fatigue testing or in applications involving vibration or cyclic stress. The underlying mechanisms of cyclic hardening and softening are complex and involve a combination of microstructural changes and stress-induced deformation. Understanding these phenomena is essential in predicting the fatigue life and durability of materials under cyclic loading conditions.