Applied Physics A

, Volume 80, Issue 8, pp 1625–1629

Size dependence of mechanical properties of gold at the sub-micron scale

Invited paper

DOI: 10.1007/s00339-005-3204-6

Cite this article as:
Greer, J. & Nix, W. Appl. Phys. A (2005) 80: 1625. doi:10.1007/s00339-005-3204-6

Abstract

The results of both experimental studies and molecular dynamics simulations indicate that crystals exhibit strong size effects at the sub-micron scale. In experimental studies, the size effects are usually explained by strain gradients. By contrast, atomistic simulations suggest that the yield strength depends on the size even without strain gradients and scales with the sample size through a power relationship. Here we address these two different approaches to the size dependence of mechanical properties. Results of uniaxial compression experiments on gold single crystals at the sub-micron scale, without significant stress/strain gradients, are presented. The free-standing single-crystal Au cylinders are created by focused ion beam machining and are subsequently compressed using a nanoindenter fitted with a diamond flat punch. Compressive stresses and strains, as well as pillar stiffnesses, are determined from the test data. The experiments show that the flow stresses of these pillars increase significantly with decreasing pillar diameter, reaching several GPa for the smallest pillars. These high strengths appear to be controlled by dislocation starvation, which is unique to small crystals.

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Department of Materials Science and EngineeringStanford UniversityStanfordUSA

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