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Title: On the scaling behavior of hardness with ligament diameter of nanoporous-Au: Constrained motion of dislocations along the ligaments

The scaling behavior of hardness with ligament diameter and vacancy defect concentration in nanoporous Au (np-Au) has been investigated using a combination of Vickers Hardness, Scanning electron microscopy, and positron lifetime measurements. It is shown that for np-Au, the hardness scales with the ligament diameter with an exponent of −0.3, that is, at variance with the conventional Hall-Petch exponent of −0.5 for bulk systems, as seen in the controlled experiments on cold worked Au with varying grain size. The hardness of np-Au correlates with the vacancy concentration C{sub V} within the ligaments, as estimated from positron lifetime experiments, and scales as C{sub V}{sup 1/2}, pointing to the interaction of dislocations with vacancies. The distinctive Hall-Petch exponent of −0.3 seen for np-Au, with ligament diameters in the range of 5–150 nm, is rationalized by invoking the constrained motion of dislocations along the ligaments.
Authors:
; ; ; ; ; ;  [1]
  1. Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, TamilNadu (India)
Publication Date:
OSTI Identifier:
22300054
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 23; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ABUNDANCE; DEFECTS; DISLOCATIONS; GOLD; GRAIN SIZE; HARDNESS; INTERACTIONS; LIFETIME; LIGAMENTS; POROUS MATERIALS; POSITRONS; SCALING; SCANNING ELECTRON MICROSCOPY; VICKERS HARDNESS NANOPARTICLES