Grain Boundary Mobility
The ability of crystal boundaries to shift under thermal or mechanical activation. This is crucial for recrystallization and grain growth.
Physicochemical Mechanism of Action
Crystalline boundaries can move under the influence of temperature or mechanical forces. This movement allows the crystal lattice to be reshaped and new grains to grow.
Metallurgical Relevance & Welding Risks
High grain boundary mobility can lead to a finer grain structure, which increases strength. However, it can also lead to a coarser structure if the material is not cooled properly. This can affect toughness and stress resistance.
Workshop Practice & Action Guidelines
To ensure optimal grain boundary mobility, it is important that the material is cooled in a controlled environment. This means strictly following the cooling curve and time. For steels with high carbon content (e.g., HSS), slow cooling should be used to avoid coarse structures. For low carbon content (e.g., SS), rapid cooling may be beneficial to achieve a fine grain.