Local Activation Gradient
The local activation gradient describes differences in the energy required for thermal processes due to unequal stress fields. It affects diffusion and reaction rates locally.
Physical-Chemical Mechanism of Action
The local activation gradient arises from inhomogeneous stress fields in the material, causing different energy requirements for thermal processes such as melting or cooling. These differences lead to local variations in diffusion and reaction rates.
Metallurgical Relevance & Welding Risks
An uneven activation gradient can lead to the development of porosity, cracks, or microstructural inhomogeneities. This can impair the strength and mechanical properties of the weld.
Workshop Practice & Action Instructions
To ensure a homogeneous activation gradient, it is important to maintain a uniform stress field in the material. This can be achieved by careful preparation and adhering to the correct welding parameters. For complex components or when using dissimilar materials, the stress field should be regularly checked and controlled.