Mechanical Tasts of Nanocrystalline Specimens

Zbigniew Pakieła 

Warsaw University of Technology, Faculty of Materials Science and Engineering (InMat), Wołoska 141, Warszawa 02-507, Poland


Mechanical tests of nanocrystalline specimens
Zbigniew Pakiel/a
Faculty of Materials Science and Engineering, Warsaw University of
Nanocrystalline materials must be often examined using
very small specimens, and the reasons why this is so are: many
technological processes permit us to prepare only small specimens.
Often we need to examine small components of electro-mechanical
Problems arising in the strength examinations of
micro-specimens can be classified into 5 groups: cutting the
specimens, mounting the specimens, accuracy in controlling the loading
force and resulting strain, strain measurement, force measurement.
The production of nanomaterials by plastic straining is difficult
because of strain localisation in bands. The present study was
concerned with the effects of various straining parameters on the
microstructure and mechanical properties obtained. The effect of heavy
deformation and associated refinement of the microstructure was
achieved by the three methods: high-pressure torsion, equal channel
extrusion, and multiple rolling.
The materials examined belonged to various classes. It has
been found that in single-phase materials, plastic deformation results
in a nanocrystalline structure being formed. The strongest refinement
of the grains was achieved when using high-pressure torsion. The
average grain sizes ranged here from 20 to 100nm. This method has
however a drawback in that the samples obtained have small volumes.
Equal-channel extrusion gives greater sample volumes but the grain
size usually exceeds 100nm. In the intermetallic matrix materials,
the heavy deformation brought about the partial or total lost of the
long-range order and an increase of the material plasticity. The
ordering was recovered and the plasticity eliminated by subjecting the
material to annealing.

Legal notice
  • Legal notice:

    Copyright (c) Pielaszek Research, all rights reserved.
    The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
    In every case, proper references including Author(s) name(s) and URL of this webpage: must be provided.


Related papers
  1. Investigation of fatique crack growth rate of Al 5484 ultrafine grained alloy after ECAP process
  2. Ductility of Nanocrystalline Materials Processed by Severe Plastic Deformation
  3. Excellent Mechanical Properties of Nickel Processed by High Pressure Techniques
  4. Mechanical properties nanostructured iron obtained by different methods of Severe Plastic Deformation
  5. Strain localization in nanocrystalline iron after Severe Plastic Deformation
  6. The Superplasticity of Hard Magnetic Alloy Fe-23wt.%Co-30%Cr with Submicrocrystalline Structure
  7. Microstructural Inhomogeniety Observed in Iron Subjected to Torsion Under High Pressure
  8. The Structure and Mechanical Properties of Low Carbon Low Alloy Steel Subjected to Severe Plastic Deformation

Presentation: oral at E-MRS Fall Meeting 2002, by Zbigniew Pakieła
See On-line Journal of E-MRS Fall Meeting 2002

Submitted: 2003-02-16 17:33
Revised:   2009-06-08 12:55
© 1998-2022 pielaszek research, all rights reserved Powered by the Conference Engine