Deformation Twinning
Deformation twinning is a plastic deformation process in which parts of the crystal lattice are shifted into a mirrored orientation. This allows additional deformation and occurs mainly in body-centered cubic or hexagonal metals.
Physical-Chemical Mechanism of Action
During deformation twinning, part of the crystal lattice reorients into a mirror image. This happens by shearing of atoms within the lattice, creating additional degrees of freedom for deformation.
Metallurgical Relevance & Welding Risks
These processes can lead to increased resistance to plastic deformation and to the formation of cracks or hardness issues in the weld. Incorrect cooling conditions or excessive loading during welding can promote twinning and impair the microstructure.
Workshop Practice & Instructions
To minimize deformation twinning, it is important to ensure controlled cooling of the weld. This can be achieved by using cooling wall systems or applying coolants. The maximum load during welding should be kept below the specific limits for the material used to ensure homogeneous cooling and a stable microstructure.