Cellular Solidification Structure
Cellular structure forms during directional solidification of metals due to undercooling effects. It develops before dendritic growth and has a cell-like microstructure.
Physical-Chemical Mechanism of Action
In directional solidification of metals, the cellular structure forms through the balancing reaction between phases. The liquid undercools in microscopic regions, creating small crystal cells. These cells are often polygonal and have a regular structure.
Metallurgical Relevance & Welding Risks
The cellular structure can appear when there are errors in weld process control, like too-fast cooling or insufficient alloy dilution. It leads to a coarser microstructure and can impair the material's mechanical properties. It can also increase susceptibility to cracking and corrosion.
Workshop Practice & Action Items
To avoid cellular structure, careful control of the welding process is essential. Make sure cooling is controlled and slow (t8/5 between 10-20 seconds). Use proper dilution agents and watch the correct weld temperature. If needed, you can use special processes like TIG welding to optimize the microstructure.