Loss of Precipitate Coherency
The loss of lattice continuity between precipitates and matrix leads to dislocations at the interface, which reduces the maximum hardening effect.
Physical-chemical mechanism of action
Loss of coherence of precipitates occurs when a growing precipitate separates from the matrix. This happens through the formation of dislocations at the interface between the precipitate and the matrix. These dislocations interrupt lattice continuity and prevent the precipitate from being fully integrated into the matrix.
Metallurgical relevance & risks in welding
Loss of coherence leads to a reduction in the hardening effect of the precipitates. This can cause the weld to become less strong and more prone to cracking. Especially at high stresses or mechanical loads, loss of coherence can lead to hot cracks or fractures in the weld.
Workshop practice & instructions
To minimize loss of coherence, it is important to carefully control welding parameters such as temperature and time. Too high a welding temperature can cause rapid growth of precipitates and prevent them from fully integrating into the matrix. Too long a cooling process can also lead to the formation of dislocations at the interface. It is recommended to use an optimal welding temperature and a controlled cooling process.