Dendritic solidification growth
Dendritic solidification growth is the tree-like branched crystal formation during cooling of a melt, caused by thermal and constitutional undercooling. It shapes the cast and welded structure.
Physical-Chemical Mechanism of Action
During cooling of a melt, thermal and concentration-related differences in the temperature field arise. These differences lead to local solidifications that develop into tree-like branched crystal structures – the dendrites. This process is especially pronounced at high cooling rates and uneven cooling paths.
Metallurgical Relevance & Welding Risks
Dendritic solidification growth can lead to fine, glass-hard structures that are prone to cracks and fracture. It can also lead to uneven stress distribution and thus to corrosion setting. In welding technology, it can lead to hot cracks and coarsened structure, which impairs mechanical properties.
Workshop Practice & Instructions
To minimize dendritic solidification growth, controlled cooling should be ensured. This can be achieved by choosing the appropriate welding process and the right cooling strategy. In casting processes, it is important to ensure homogeneous cooling, e.g., by using cooling water or air cooling systems. In welding, slow and controlled cooling after welding can help prevent the growth of dendrites.