Experimental Investigations of the Dynamics of Plc Bands in Al3%Mg

The Portevin-Le Chatelier (PLC) effect is an undesired behaviour of ductile alloys consisting in a regime of unstable plastic deformation. A relevant feature of this phenomenon is the repetitive concentration of the strain in narrow regions, referred to as PLC bands, that resemble incipient neckings. Depending on the loading conditions and on material factors, three different kinds of band behaviour are traditionally distinguished in tensile tests: type A, a band moving with a constant velocity as a regular and continuous propagation along the specimen; type B, a series of stationary bands that emerge one beside the other at regular intervals in time and in space; type C, stationary bands that emerge with a regular frequency but disordered in space, [1]. Whereas this is a well established classification, the way in which a single band actually emerges is still an open question, but only in the last years a few investigations could start to deal with this aspect, [2] and [3].