Stability of shear banding process in bulk metallic glasses and composites
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Jianguo Wang School of Materials Science and Engineering, Anhui University of Technology, Ma’anshan 243002, People’s Republic of China
Baoan Sun Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, People’s Republic of China
Baran Sarac Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Leoben A-8700, Austria
Florian Spieckermann Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Leoben A-8700, Austria; and Department Materials Physics, Montanuniversität Leoben, Leoben A-8700, Austria
Gang Wang Laboratory for Microstructures, Shanghai University, Shanghai 200444, People’s Republic of China
Ivan Kaban IFW Dresden, Institute for Complex Materials, Dresden D-01069, Germany
Jürgen Eckertc) Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Leoben A-8700, Austria; and Department Materials Physics, Montanuniversität Leoben, Leoben A-8700, Austria (Received 23 April 2017; accepted 26 May 2017)
The shear-band propagation in bulk metallic glasses (BMGs) during deformation plays a key role in determining their macroscopic ductility. In this work, the shear band propagation during plastic deformation was investigated in the Cu46Zr46Al8 BMG and its in situ or ex situ prepared BMG composites. Compared with the brittle BMG, both types of ductile BMG composites show a more stable shear banding behavior as revealed by a larger power-law scaling exponent obtained from statistical analysis of serrations recorded in compressive curves. A higher cut-off elastic energy density (dc) linked with the multiplication of shear bands is observed for the in situ prepared BMG composites. However, the ex situ fabricated BMG composites show an almost equivalent or slightly larger dc since the dominant shear band but not multiple shear bands mainly governs their deformation. Such observations imply that the shear banding stability of BMGs during deformation is enhanced not only by inducing multiple shear bands but also by obstructing the movement of the dominant shear band at its driven path. I. INTRODUCTION
As an emerging class of structural materials, bulk metallic glasses (BMGs) with excellent mechanical
Contributing Editor: Mathias Göken Address all correspondence to these authors. a) e-mail: [email protected] b) e-mail: [email protected] c) This author was an editor of this journal during the review and decision stage. For the JMR policy on review and publication of manuscripts authored by editors, please refer to http://www.mrs. org/editor-manuscripts/. DOI: 10.1557/jmr.2017.243
properties have attracted much attention.1–4 However, at temperatures far below the glass transition and at high stresses, inhomogeneous plastic flow localized within narrow regions, being termed as shear bands, strongly governs both strength and ductility of BMGs.5–7 Recent studies have demonstrated that a remarkable enhancement of the compressive plasticity of BMGs can be achieved by changing intrinsic properties of BMGs, extri
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