Cyclic Softening
Cyclic softening reduces stress to maintain a constant plastic strain amplitude under repeated loading. It occurs in cold-worked or precipitation-hardened materials.
Physicochemical mechanism of action
Under cyclic loading, materials can undergo so-called softening. This means that the stress required to achieve a constant plastic strain amplitude decreases over time. This effect occurs due to microstructural changes and grain size adjustments in the material.
Metallurgical relevance & risks in welding
Cyclic softening can lead to an increased service life of components, as it reduces stress levels and thus prevents crack formation. However, it can also lead to undesirable changes in mechanical properties if not properly considered. In welding, it is important to design the loading and material so that softening is optimally utilized.
Workshop practice & action guidelines
To utilize cyclic softening in practice, the following measures should be taken:
• Use materials with low susceptibility to cyclic softening.
• Ensure that the loading on the material remains within a suitable stress range.
• For cold-worked or precipitation-hardened materials, pay attention to proper cooling and post-weld treatment.