Grain Boundary Segregation in Additive Microstructure
Alloying elements concentrate at grain boundaries during rapid cooling, leading to uneven properties.
Physical-Chemical Mechanism of Action
Additive manufacturing involves high cooling rates. This causes alloying elements to concentrate at the highly directional grain boundaries. Rapid cooling prevents uniform distribution of elements in the material.
Metallurgical Relevance & Welding Risks
Grain boundary segregation can lead to uneven mechanical properties within the material. This can cause cracks, distortion, and reduced weld toughness. Enrichment of certain elements at grain boundaries can also reduce resistance to chemical influences.
Shop Practice & Action Instructions
To minimize grain boundary segregation, maintain slow cooling rates in additive processes. Achieve this by optimizing melting speed and using stabilizing additives. With high cooling rates, carefully control alloying elements to avoid uneven properties.