Peculiar Spatiotemporal Behavior of Unstable Plastic Flow in an AlMgMnScZr Alloy with Coarse and Ultrafine Grains
Daria Zhemchuzhnikova,
Mikhail Lebyodkin,
Tatiana Lebedkina,
Anna Mogucheva,
Diana Yuzbekova,
Rustam Kaibyshev
Affiliations
Daria Zhemchuzhnikova
Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), CNRS UMR 7239, Université de Lorraine, 7 rue Félix Savart, BP 15082, 57073 Metz CEDEX 03, France
Mikhail Lebyodkin
Laboratoire d’Etude des Microstructures et de Mécanique des Matériaux (LEM3), CNRS UMR 7239, Université de Lorraine, 7 rue Félix Savart, BP 15082, 57073 Metz CEDEX 03, France
Tatiana Lebedkina
Center of Excellence “LabEx DAMAS”, Université de Lorraine, 7 rue Félix Savart, 57073 METZ, France
Anna Mogucheva
Laboratory of the Mechanical Properties of Nanoscale Materials and Superalloys, Belgorod State University, Pobedy Street 85, Belgorod 308015, Russia
Diana Yuzbekova
Laboratory of the Mechanical Properties of Nanoscale Materials and Superalloys, Belgorod State University, Pobedy Street 85, Belgorod 308015, Russia
Rustam Kaibyshev
Laboratory of the Mechanical Properties of Nanoscale Materials and Superalloys, Belgorod State University, Pobedy Street 85, Belgorod 308015, Russia
The work addresses the effects of nanosize particles and grain refinement on the patterns of stress serrations and kinematics of deformation bands associated with the Portevin–Le Chatelier instability of plastic flow. Ultra-fine-grained microstructure was obtained using equal-channel angular pressing of the initial coarse-grained alloy. Tensile tests were carried out on flat specimens at strain rates in the range from 3 × 10−5 to 1.4 × 10−2 s−1. Using local extensometry techniques, it was found that the presence of nanoscale precipitates promotes quasi-continuous propagation of deformation bands in the entire strain-rate range. The grain refinement leads to a transition to relay-race propagation at high strain rates and static strain localization at low rates. The results are discussed from the viewpoint of competition between various dynamical modes of plastic deformation associated with collective dynamics of dislocations.
