Loss of Coherence
Loss of coherence occurs when the crystal lattice between a precipitate and the matrix is too severely distorted. This reduces hardness efficiency.
Physical-chemical mechanism of action
Loss of coherence occurs when a precipitate grows in a metal and the crystal lattice between the precipitate and the matrix becomes too severely distorted. These elastic distortions increase until they eventually interrupt the coherence between the two phases.
Metallurgical relevance & risks in welding
Loss of coherence can lead to a reduction in hardness and toughness of the material. This increases the risk of cracks and failure under mechanical load. In the weld zone, loss of coherence can occur if the metal cools too quickly or if the additives are not properly intertwined.
Workshop practice & instructions
To avoid loss of coherence, it is important that the metal cools slowly and controlled. This can be achieved by sufficient post-treatment or by using shielding gases. Additionally, the additives should be added in the right concentration and at the right time to ensure homogeneous intertwining.