Analysis of plastic instability in commercially pure Al alloys

The present work deals with sequences of rolling-shear experiments conducted on an Al 1050 alloy. Particular attention was paid to the transient mechanisms produced by a change of loading mode. It is shown that the flow behaviour during shearing strongly depends on the amplitude in the strain path change. More precisely, plastic instabilities take place just after yielding only for shear tests performed at some definite orientations from the rolling direction. It is shown that such a mechanical anisotropy is related to the deformation texture. The texture evolution is evaluated through self-consistent calculations. Flow softening is obtained when the Taylor factor, estimated with the model, decreases.