Skip to main content
eScholarship
Open Access Publications from the University of California

Multiscale analysis of nanoindentation-induced defect structures in gum metal

  • Author(s): Sankaran, RP
  • Ozdol, VB
  • Ophus, C
  • Kacher, J
  • Gammer, C
  • Govindjee, S
  • Minor, AM
  • Morris, JW
  • et al.
Abstract

© 2018 Acta Materialia Inc. Using ex-situ transmission electron microscopy and the recently developed nanoprobe diffraction (NPD) technique, we characterize a nanoindented solution treated gum metal. Lattice rotations are resolved at a 1.2 nm length-scale and shown to be continuous within the nanoindentation pit; further, it is shown that these can be accommodated by a reasonable number of geometrically necessary dislocations at a density of ∼1015/m2. We additionally provide direct evidence that dislocations within the nanoindent, rather than secondary phase nanoparticles, can serve as potent barriers to dislocation motion. We also demonstrate that plasticity in these alloys under nanoindentation can be accommodated solely by dislocation nucleation and propagation, with no competing deformation mechanisms present. Conventional transmission electron microscopy and “g•b” analysis reveal the presence of dislocations on 〈1¯11〉{110} slip systems and highly localized plastic deformation in the form of shear bands on <111>{1¯1¯2} slip systems, similar to previously observed “giant faults”.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View