Dynamic strain aging

Although sometimes dynamic strain aging is used interchangeably with the Portevin–Le Chatelier effect (or serrated yielding), dynamic strain aging refers specifically to the microscopic mechanism that induces the Portevin–Le Chatelier effect.

This strengthening mechanism is related to solid-solution strengthening and has been observed in a variety of fcc and bcc substitutional and interstitial alloys, metalloids like silicon, and ordered intermetallics within specific ranges of temperature and strain rate.

[2] This process's most well-known macroscopic manifestations are Lüders bands and the Portevin–Le Chatelier effect.

[5] An edge dislocation produces a stress field which is compressive above the slip plane and tensile below.

The first class of Elements, such as carbon(C) and nitrogen(N), contribute to DSA directly by diffusing quickly enough through the lattice to the dislocations and locking them.

Arising from the repeated nucleation of shear bands and the continuous propagation of Lüders bands, this type consists of periodic locking serrations with abrupt increase in flow stress followed by drop of stress below the general level of the stress-strain curve.

Caused by dislocation unlocking, the stress drop of type C is below the general level of the flow curve.

Stress field around an edge dislocation core, with schematic atomic positions overlaid. The filled circles represent larger substitutional impurities, which are driven across the slip plane during dynamic strain aging (shown by the arrow).