skip to main content

Title: Composition and grain size effects on the structural and mechanical properties of CuZr nanoglasses

Nanoglasses (NGs), metallic glasses (MGs) with a nanoscale grain structure, have the potential to considerably increase the ductility of traditional MGs while retaining their outstanding mechanical properties. We investigated the effects of composition on the structural and mechanical properties of CuZr NG films with grain sizes between 3 to 15 nm using molecular dynamics simulations. Results indicate a transition from localized shear banding to homogeneous superplastic flow with decreasing grain size, although the critical average grain size depends on composition: 5 nm for Cu{sub 36}Zr{sub 64} and 3 nm for Cu{sub 64}Zr{sub 36}. The flow stress of the superplastic NG at different compositions follows the trend of the yield stress of the parent MG, i.e., Cu{sub 36}Zr{sub 64} yield/flow stress: 2.54 GPa/1.29 GPa and Cu{sub 64}Zr{sub 36} yield/flow stress: 3.57 GPa /1.58 GPa. Structural analysis indicates that the differences in mechanical behavior as a function of composition are rooted at the distinct statistics of prominent atomic Voronoi polyhedra. The mechanical behavior of NGs is also affected by the grain boundary thickness and the fraction of atoms at interfaces for a given average grain size. The results suggest that the composition dependence of the mechanical behavior of NGs follows that of their parent MGs, e.g., a stronger MGmore » will generate a stronger NG, while the intrinsic tendency for homogeneous deformation occurring at small grain size is not affected by composition.« less
Authors:
 [1] ;  [2] ; ;  [1] ;  [3]
  1. Institute of High Performance Computing, A*STAR, 138632 Singapore (Singapore)
  2. (Singapore)
  3. Mechanical Engineering Department, National University of Singapore, 117576 Singapore (Singapore)
Publication Date:
OSTI Identifier:
22308525
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COPPER COMPOUNDS; CRYSTAL STRUCTURE; DEFORMATION; DUCTILITY; FILMS; FLOW STRESS; GRAIN BOUNDARIES; GRAIN SIZE; INTERFACES; MAGNESIUM SULFIDES; MECHANICAL PROPERTIES; METALLIC GLASSES; MOLECULAR DYNAMICS METHOD; NANOMATERIALS; NANOSTRUCTURES; PRESSURE RANGE GIGA PA; SIMULATION; THICKNESS; ZIRCONIUM COMPOUNDS