Incoherent Precipitates
Incoherent precipitates are second phases with a different crystal structure and lack of lattice continuity at the interfaces. They cause elastic stress fields of lower intensity, which, however, cannot be directly cut by dislocations.
Physico-chemical mechanism of action
Incoherent precipitates form by the insertion of a second phase into a metal matrix. This has a different crystal structure and lacks lattice continuity at the interfaces to the matrix. The stress fields that result from this are elastic and have lower intensity than coherent precipitates.
Metallurgical relevance & risks in welding
Incoherent precipitates can lead to a reduction in the toughness of the material. They cause stress fields that cannot be directly cut by dislocations, which can lead to local cracks or deformations. This is particularly critical in highly loaded components.
Workshop practice & operating instructions
To minimize incoherent precipitates, the weld should be placed in such a way that it generates as little stress fields as possible. This can be achieved by optimal heat treatment and careful selection of welding consumables. For highly loaded parts, it is important to control stress fields and, if necessary, incorporate additional dislocations.