Ostwald ripening

A process where smaller precipitates or particles in a matrix dissolve while larger ones grow at their expense. The driving force is the reduction of total interfacial energy in the microstructure.

Ostwald ripening is the effect where small precipitates or grains in the weld disappear over time and larger ones grow at their expense. This happens because the interfacial energy is minimized. For welding, this means: if the weld stays too hot after welding or you have high heat input, the microstructure can coarsen. This can make the weld softer and tougher, but it can also reduce strength. So if you need a fine-grained structure, you have to keep an eye on cooling and keep heat input low.

MetallurgieSchweißtechnik