The Bauschinger effect and discontinuous yielding

Abstract

Although the most popular definition of the Bauschinger effect refers to the lowering of the yield stress for reversed loading, the effect is more complex than was previously thought and it involves not only the initial yield strength, but the entire stress—strain curve after prestraining. The principal causes are believed to be associated with elastic stress and/or anisotropy in the resistance to dislocation motion. An experiment designed to test the Bauschinger effect, under the special ocnditions of discontinuous yielding in mild steel, is described. Three parameters are introduced for the evaluation and interpretation of the results. The density of mobile dislocations created by prestrain seems to be the most important factor affecting the magnitude of the Bauschinger effect. Using a new interpretation it is shown that the Bauschinger effect is greater the smaller the prestrain.