Microstructural and mechanical influences on dynamic strain aging phenomena

The Portevin-Le Chatelier (PLC) effect is a manifestation of macroscopic scale non-uniformities which have their origins on a microstructural level. The coordination of dislocation level events within grains, across grain boundaries, and eventually on to the level of a test specimen or workpiece make the PLC effect subject to a large range of variables. An holistic approach which examines the effect across this spectrum of variables potentially allows for a clearer overview of the phenomenon. This review covers experimental work which deals with a full range of the variables. Aspects discussed include manifestations of dynamic strain aging, the occurrence or not of one or more critical strains, the formation of deformation bands, and the effects of specimen geometry. In addition, an examination of the influence of microstructural variables including the solute concentration, grain size, and accumulated prior strain are presented. Dynamic strain aging related phenomena continue to receive regular attention in the literature and theoretical modelling has been developed to the point where qualitative agreement exists with specific aspects such as the critical strains. Modelling of the effect is, however, beyond the scope of this review.