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Corrosion
Row of industrial heat exchangers .
IV . Susceptibility to stress intensity
• Transgranular SCC is often more sensitive to stress intensity factors , and the conditions that promote crack initiation and growth can be more localized .
2 . Intergranular SCC Definition : Intergranular SCC involves cracking that occurs across the grain boundaries of the material . Mechanism : The mechanism of intergranular
SCC is characterized by cracks following the grain boundaries , impacting the integrity of the material at the interfaces between grains . Key aspects of the mechanism include : I . Path along grain boundaries
• Cracks propagate along the boundaries between adjacent grains , creating a path that extends across the material .
• The intergranular nature of the cracking distinguishes it from transgranular SCC , where the cracks penetrate through individual grains .
II . Changes in microstructure
• Intergranular SCC is often associated with changes in the material ’ s microstructure , such as sensitization or precipitation of certain phases .
• These changes make specific grain boundaries more susceptible to cracking , often due to the formation of less corrosion-resistant phases .
III . Sensitization and precipitation
• Sensitization refers to the depletion of corrosionresistant elements near the grain boundaries , making these regions more susceptible to corrosive attack .
• Precipitation of less corrosion-resistant phases along the grain boundaries can promote crack initiation and propagation .
IV . Selective attack on grain boundaries
• The cracking in intergranular SCC selectively targets grain boundaries , leading to a more distributed and interconnected network of cracks compared to transgranular cracking .
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