Piobert–Lüders plateau and Portevin–Le Chatelier effect in an Al–Mg alloy in simple shear

The jerky flow in an Al–Mg alloy is studied during simple shear tests at room temperature and various strain rates. Direct observations of the sample surface using digital image correlation allow the study of the type and the dynamics of bands associated to plastic instabilities as a function of shear strain and shear strain rate. The paper features that both Piobert–Lüders and Portevin–Le Chatelier phenomena can be observed for a simple shear stress state at room temperature. The nucleation, growth and movement of the bands are described: it is shown that the kinematics of the bands is similar to those observed in tension but that the orientation of the bands varies with the shear strain.

► PLC bands are observed in shear tests on an Al–Mg alloy for 3 strain rates with DIC. ► Both Piobert–Lüders and Portevin–Le Chatelier phenomena are noted. ► PLC bands kinematics are somewhat similar to those in tension. ► Orientation of the PLC bands varies with the shear strain value.Figure optionsDownload full-size imageDownload as PowerPoint slide