Precipitation Coarsening Kinetics
Precipitate coarsening kinetics describes how larger particles in a metal form from smaller ones and reduce the surface area. This leads to a loss of strength over time.
Physical-Chemical Mechanism
Precipitate coarsening kinetics is a process where larger crystallites form from smaller ones in a metal. This occurs through the diffusion of atoms on the surfaces of small particles and their attraction to large particles. The total surface area of the precipitates decreases, reducing the surface energy.
Metallurgical Relevance & Welding Risks
This process can lead to a loss of strength because larger particles have less toughness than smaller ones. In the workshop, this can cause cracking or wear problems over time, especially under high loads and temperatures.
Workshop Practice & Actions
To minimize precipitate coarsening kinetics, it is important to stabilize the weld and keep the microstructure uniform. This can be achieved through proper heat treatment. Use a controlled cooling profile during cooling to regulate grain sizes. A t8/5 value between 10 and 20 seconds is often recommended to achieve a balanced grain structure.