Nucleation work
The energy required to form and develop a new crystal grain in the melt.
Physico-chemical Mechanism of Action
The nucleation work is the energy required to form a stable solid phase from a liquid melt or parent phase. It describes the effort needed to arrange atoms in a crystal lattice.
Metallurgical Relevance & Welding Risks
High nucleation work can lead to a fine and homogeneous structure of the material. This improves mechanical properties such as strength and toughness. However, it also increases the likelihood of cracks and hot cracks if the weld cools too quickly.
Workshop Practice & Instructions
To ensure optimal nucleation, it is important to control the cooling rate of the weld. This can be achieved by selecting the appropriate shielding gas and correct welding parameters. Too rapid cooling leads to high nucleation work and increases the risk of cracking, while too slow cooling results in a fine structure.