Dislocation Pile-Up
Dislocation pile-up is the accumulation of dislocations at obstacles such as grain boundaries or carbides, leading to high stresses and possible microcracks.
Physicochemical Mechanism of Action
Dislocation pile-up forms when dislocations gather at obstacles they can't overcome, like grain boundaries or carbides. These dislocations can't move anymore, creating a sort of blockade.
Metallurgical Relevance & Welding Risks
The high stress concentration at pile-ups can lead to microcracks, which can grow into larger cracks over time. This increases the risk of hot cracking and reduces the toughness of the material.
Workshop Practice & Action Guidelines
To minimize dislocation pile-ups, careful material selection is important: use steels with low dislocation density and make sure the welding procedure is correct. For high-dislocation steels, using hardening agents or tempering can help.