Intermetallic Diffusion Phase
Intermetallic diffusion phases are brittle structure layers that form at the interface through interaction between the molten filler metal and the base material. They affect the toughness of the weld metal.
Physical-Chemical Mechanism of Action
Intermetallic diffusion phases form through the exchange of atoms between the molten filler metal and the base material at the interface. This leads to the formation of a new, brittle phase with different properties than the original metal.
Metallurgical Relevance & Risks in Welding
These phases can reduce the toughness of the weld metal and lead to brittleness. They increase susceptibility to cracking and can impair behavior under mechanical stress. An excessively high proportion of diffusion phases can cause the weld to be insufficiently strong.
Workshop Practice & Instructions
To minimize diffusion phases, the filler metal and base material should be well prepared. This includes thorough cleaning and removal of dirt and corrosion. Optimal temperature control during welding is crucial. For heavy metals like steel, the hardness of the weld should be checked to ensure there is not an excessive amount of diffusion phases.