Atomistic simulation of tantalum nanoindentation: Effects of indenter diameter, penetration velocity, and interatomic potentials on defect mechanisms and evolution
Artikel i vetenskaplig tidskrift, 2014

Nanoindentation simulations are a helpful complement to experiments. There is a dearth of nanoindentation simulations for bcc metals, partly due to the lack of computationally efficient and reliable interatomic potentials at large strains. We carry out indentation simulations for bcc tantalum using three different interatomic potentials and present the defect mechanisms responsible for the creation and expansion of the plastic deformation zone: twins are initially formed, giving rise to shear loop expansion and the formation of sequential prismatic loops. The calculated elastic constants as function of pressure as well as stacking fault energy surfaces explain the significant differences found in the defect structures generated for the three potentials investigated in this study. The simulations enable the quantification of total dislocation length and twinning fraction. The indenter velocity is varied and, as expected, the penetration depth for the first pop-in (defect emission) event shows a strain rate sensitivity m in the range of 0.037-0.055. The effect of indenter diameter on the first pop-in is discussed. A new intrinsic length-scale model is presented based on the profile of the residual indentation and geometrically necessary dislocation theory.

Nanoindentation

Plasticity

Twinning

SURFACE INDENTATION

MD simulation

MICRO-INDENTATION

TEMPERATURE-DEPENDENCE

METALLIC MATERIALS

STRAIN GRADIENT PLASTICITY

MOLECULAR-DYNAMICS SIMULATIONS

Tantalum

NUCLEATION

INDENTATION EXPERIMENTS

DISLOCATION

SINGLE-CRYSTALS

SPHERICAL INDENTATION

Författare

C. J. Ruestes

University of California

Consejo Nacional De Investigaciones Cientificas Y Tecnicas

Universidad Nacional de Cuyo

A. Stukowski

Technische Universität Darmstadt

Y. Tang

Shanghai University

Diego Tramontina

Universidad Nacional de Cuyo

Paul Erhart

Chalmers, Teknisk fysik, Material- och ytteori

B. A. Remington

Lawrence Livermore National Laboratory

H. M. Urbassek

Technische Universität Kaiserslautern

M. A. Meyers

University of California

Eduardo Bringa

Consejo Nacional De Investigaciones Cientificas Y Tecnicas

Universidad Nacional de Cuyo

Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

0921-5093 (ISSN)

Vol. 613 390-403

Ämneskategorier

Materialteknik

Styrkeområden

Materialvetenskap

DOI

10.1016/j.msea.2014.07.001