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Title: Science at the interface : grain boundaries in nanocrystalline metals.

Interfaces are a critical determinant of the full range of materials properties, especially at the nanoscale. Computational and experimental methods developed a comprehensive understanding of nanograin evolution based on a fundamental understanding of internal interfaces in nanocrystalline nickel. It has recently been shown that nanocrystals with a bi-modal grain-size distribution possess a unique combination of high-strength, ductility and wear-resistance. We performed a combined experimental and theoretical investigation of the structure and motion of internal interfaces in nanograined metal and the resulting grain evolution. The properties of grain boundaries are computed for an unprecedented range of boundaries. The presence of roughening transitions in grain boundaries is explored and related to dramatic changes in boundary mobility. Experimental observations show that abnormal grain growth in nanograined materials is unlike conventional scale material in both the level of defects and the formation of unfavored phases. Molecular dynamics simulations address the origins of some of these phenomena.
Authors:
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Publication Date:
OSTI Identifier:
974872
Report Number(s):
SAND2009-5751
TRN: US201008%%417
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Research Org:
Sandia National Laboratories
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; NANOSTRUCTURES; INTERFACES; GRAIN BOUNDARIES; GRAIN GROWTH; GRAIN SIZE; NICKEL; WEAR RESISTANCE; MOLECULAR DYNAMICS METHOD; Nanocrystals.; Nanostructures.; Nanostructure materials-Analysis.