Near-Perfect Elastoplasticity in Pure Nanocrystalline Copper
Yannick Champion,1*
Cyril Langlois,1
Sandrine Guérin-Mailly,1
Patrick Langlois,2
Jean-Louis Bonnentien,1
Martin J. H
tch1
Ductile metals and alloys undergo plastic yielding at
room temperature, during which they exhibit work-hardening and the
generation of surface instabilities that lead to necking and failure.
We show that pure nanocrystalline copper behaves differently,
displaying near-perfect elastoplastic behavior characterized by
Newtonian flow and the absence of both work-hardening and neck
formation. We observed this behavior in tensile tests on fully dense
large-scale bulk nanocrystalline samples. The experimental results
further our understanding of the unique mechanical properties of
nanocrystalline materials and also provide a basis for commercial
technologies for the plastic (and superplastic) formation of such
materials.
1 Centre d'Etudes de Chimie
Métallurgique-CNRS, 15 rue Georges Urbain, 94407 Vitry-sur-Seine, France.
2 Laboratoire
d'Ingénierie des Matériaux et des Hautes
Pressions-CNRS, Université Paris XIII, 99 avenue J.-B.
Clément, 93430 Villetaneuse, France.
*
To whom correspondence should be addressed. E-mail:
yannick.champion{at}glvt-cnrs.fr
