In some specimens the structure of the strain increment associated with discontinuous yielding is quite repeatable.
The discontinuous yielding in build 2 Vertical specimens is longer, and its structure differs from the horizontal specimens of all three builds.
Heat treatment reduces the discontinuous yielding region in the vertical specimens, but does not change the general shape.
The low-strain structure of the stress-strain curve in the discontinuous yielding region is caused by the formation and propagation of two Luders bands, which nucleate at the ends of the gauge length and propagate until they meet in the center of the specimen.
The stress-strain curves exhibit several artifacts that are known [28,29] to be created by the interaction of the discontinuous yielding or Luders bands, the specimen geometry and surface finish, and the geometry of the extensometer.
The large discontinuous yielding strain in all tests resulted from the formation and propagation of Luders bands: Fig.