Microstructural Relaxation
Microstructure relaxation is the process by which internal lattice distortions in metals are reduced through ordered atomic displacements. This reduces the risk of cracks and increases mechanical strength.
Physical-chemical mechanism
Microstructure relaxation occurs when metals cool from the liquid melt phase to the solid state. During cooling, atoms attempt to restore their lattice structure, leading to ordered displacement processes that compensate for internal distortions.
Metallurgical relevance & risks in welding
Insufficient microstructure relaxation can cause cracks to form in the weld, especially if cooling steps are too fast or irregular. This can lead to hot cracks and reduced component lifespan.
Workshop practice & instructions
To ensure effective microstructure relaxation, the following measures should be taken:
• Use a controlled cooling step with a time of at least 10 seconds per degree Celsius temperature drop.
• Keep the weld in a protected area to ensure uniform cooling.
• Avoid sudden temperature changes and protect the weld from mechanical stress during cooling.