Supersaturated Solid Solution
A solid solution where the solvent contains more dissolved atoms than in the equilibrium state. This leads to an unstable condition with the risk of phase transformations.
Physico-chemical mechanism of action
An oversaturated solid solution is a state in which the solvent contains more dissolved atoms than it would in equilibrium at the same temperature and pressure. This state is thermodynamically unstable and leads to phase transformations such as crystal growth or precipitation of secondary phases.
Metallurgical relevance & risks in welding
In welding, an oversaturated solid solution in the weld can lead to phase transformations, such as the formation of martensite or austenite. This can result in increased hardness and toughness, but also in cracks and hot cracks, especially when cooling is too fast.
Workshop practice & instructions
To minimize the risk of phase transformations in the weld, it is important to ensure controlled cooling. This can be achieved by using a suitable shielding gas or by applying cooling water. Cooling should be slow to ensure that equilibrium is reached and no unstable phase transformations occur.