Atomistic processes of dislocation generation and plastic deformation during nanoindentation

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Acta Materialia

DOI:https://doi.org/10.1016/j.actamat.2010.10.016· OSTI ID:1000716

Begau, C. ^[1]; Hartmaier, A. ^[1]; George, Easo P ^[2]; Pharr, George M ^[3]

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1. Ruhr University, Bochum, Germany
2. ORNL
3. University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL)

To enable plastic deformation during nanoindentation of an initially defect-free crystal, it is necessary first to produce dislocations. While it is now widely accepted that the nucleation of the first dislocations occurs at the start of the pop-in event frequently observed in experiments, it is unclear how these initial dislocations multiply during the early stages of plastic deformation and produce pop-in displacements that are typically much larger than the magnitude of the Burgers vector. This uncertainty about the complex interplay between dislocation multiplication and strain hardening during nanoindentation makes a direct correlation between force-displacement curves and macroscopic material properties difficult. In this paper, we study the early phase of plastic deformation during nanoindentation with the help of large-scale molecular dynamics simulations. A skeletonization method to simplify defect structures in atomistic simulations enables the direct observation and quantitative analysis of dislocation nucleation and multiplication processes occurring in the bulk as well as at the surface.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1000716
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 3 Vol. 59; ISSN 1359-6454
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BURGERS VECTOR
CRYSTALS
DEFORMATION
DISLOCATIONS
MOLECULAR DYNAMICS METHOD
NANOSTRUCTURES
NUCLEATION
PHASE STUDIES
PLASTICITY
STRAIN HARDENING