Cyclic Softening
Cyclic softening is the stress drop at constant strain amplitude under cyclic loads. It occurs in heavily work-hardened metals and can lead to cracking.
Physicochemical mechanism of action
Cyclic softening occurs due to repeated straining and deformation under alternating stresses. With each cycle, the stress in the material structure is relieved, leading to a long-term deterioration of mechanical properties.
Metallurgical relevance & risks in welding
This softening can lead to crack formation and a reduction in material toughness. It is particularly dangerous in highly work-hardened or heat-treated materials, as the stresses cannot be relieved.
Workshop practice & action guidelines
To minimize cyclic softening, the following should be considered:
• Reduce the strain amplitude.
• Decrease the frequency of alternating stresses.
• For highly work-hardened metals, apply careful cooling and a uniform heat treatment procedure.