Dendritic solidification structure
Dendritic solidification structure forms by rapid growth of crystal arms in preferred directions during undirected solidification. It results in fine, tree-like structures.
Physical-Chemical Mechanism of Action
During cooling of melts, the crystal structure grows quickly and irregularly in preferred crystallographic directions. This leads to fine, tree-like structures with many small crystals (dendrites).
Metallurgical Relevance & Welding Risks
A dendritic solidification structure can lead to poor toughness and increased stress resistance. It increases the risk of cracks and hot cracks, especially when the material is under high pressure or heavy loads.
Workshop Practice & Instructions
To avoid a dendritic solidification structure, it is important to perform controlled cooling. This can be achieved by cooling the melt slowly or by using cooling gases. For materials that are difficult to solidify (like aluminum), the process should be carried out in a protected environment (PVD).