When materials are loaded uniaxially in one direction (e.g. in tension) into the plastic regime. Loaded to zero stress level, then reloaded in reverse direction (e.g. in compression), they may yield during the reloading, at a stress level lower than if the reloading were carried out in the original direction. Figure is the schematic representation of Bauschinger effect test.

This direction-dependent, asymmetrical yield behavior is known as the Bauschinger effect.

This effect has been widely studied since then. It is now clear that Bauschiager's discoveries dealt with only a part of the phenomenon involved and that directional behavior in the stress-strain relationship is more complex than original thought. In view of these complexities it is not surprising that many different features have been used in describing the Bauschinger effect.

For e.g.

• If a specimen is highly deformed in one direction and then immediately reloaded in the opposite direction, it began to flow in this direction at a reduced stress. This is the Bauschinger effect.

The Bauschinger effect is measured by the Bauschinger strainβ.

Originally observed in polycrystals, but later found to be present also in single crystal, the Bauschinger effect denotes a certain dependence of the flow stress and rate of work hardening on the strain history of the metal.'