Coherent Precipitates
Coherent precipitates are metal additives whose crystal lattice is seamlessly integrated into the host lattice and elastically strains it. This prevents porosity and improves strength.
Physicochemical Mechanism of Action
Coherent precipitates form when metal additions (such as silicon or titanium) are integrated into the liquid base metal during the melting process. The crystal lattices of the additives transition seamlessly into the base lattice, causing elastic stress.
Metallurgical Relevance & Risks in Welding
Coherent precipitates improve the strength and toughness of the weld, as they prevent pore formation. However, too high concentrations of additives can lead to fusion problems or excessive stress levels that cause grain coarsening and potentially cracks.
Shop Practice & Action Guidelines
To ensure coherent precipitates, the additives should be well dissolved in the melt phase. The durability of the weld depends on concentrations and the proper cooling schedule. For high-strength steels, controlled cooling is required to avoid stress.