Strain bursts in plastically deforming Molybdenum micro- and nanopillars

Michael Zaiser (1) , Jan Schwerdtfeger (2) , Andreas Schneider (3) , Carl Frick (3) , Blythe Gore Clark (3) , Patric Gruber (3, 4) , Eduard Arzt (3, 5)

1 Center for Materials Science and Engineering
2 Center for Materials Science and Engineering
3 Max-Planck-Institut für Metallforschung
4 Institut für Zuverlässigkeit von Bauteilen und Systemen
5 INM - Leibniz Institute for New Materials

Plastic deformation of micron and sub-micron scale specimens is characterized by intermittent sequences of large strain bursts (dislocation avalanches) which are separated by regions of near-elastic loading. In the present investigation we perform a statistical characterization of strain bursts observed in stress-controlled compressive deformation of monocrystalline molybdenum micropillars. We characterize the bursts in terms of the associated elongation increments and peak deformation rates, and demonstrate that these quantities follow power-law distributions that do not depend on specimen orientation or stress rate. We also investigate the statistics of stress increments in between the bursts, which are found to be Weibull distributed and exhibit a characteristic size effect. We discuss our findings in view of observations of deformation bursts in other materials, such as face-centered cubic and hexagonal metals.

Mots clés: Physical Sciences

Michael Zaiser, Jan Schwerdtfeger, Andreas Schneider, Carl Frick, Blythe Gore Clark, et al.. Strain bursts in plastically deforming Molybdenum micro- and nanopillars. Philosophical Magazine, 2009, 88 (30-32), pp.3861-3874. ⟨10.1080/14786430802132522⟩. ⟨hal-00513896⟩