doi:10.1016/j.physme.2009.03.012
Quasidynamic compaction of a mesostructural
material with inclusions reinforced by
nanocrystalline particles
M.P. Bondar*, M.A. Korchagin
1
, E.S. Obodovskii,
S.V. Panin
2
and Ya.L. Lukyanov
Lavrentyev Institute of Hydrodynamics SB RAS, Novosibirsk, 630090, Russia
1
Institute of Solid State Chemistry and Mechanochemistry SB RAS, 630128, Novosibirsk, Russia
2
Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634021, Russia
A quasidynamic compaction technique is used to produce a mesostructural composite that represents the matrix framework from the
base material filled with inclusions. The size of the latter is comparable with the matrix grain size. The mesostructural composite base is
the powder of electrolytic copper or internally oxidized copper subjected to mechanical alloying with a nanocomposite. The latter is a
mixture of 60 % of copper and 40 % of nanosized TiB
2
particles. Due to high deformations the material exhibits the microstructure self-
organization and the constant size of reinforcing TiB
2
particles in the inclusions. Mechanical properties of the mesostructural composite
exceed considerably those of the composite matrix. Mechanical properties of alloys from the internally oxidized copper matrix and 69
vol. % of TiB
2
nanoparticles are close to properties of copper-based alloys with 18 vol. % of TiB
2
nanoparticles. The electrical resistance
of the mesostructural composite with the internally oxidized copper matrix (69 vol. % of TiB
2
nanoparticles) is 24 % higher than that of
internally oxidized copper and the electrical resistance of the copper-based alloy (18 vol. % of TiB
2
nanoparticles) is 8 % higher.
Keywords: quasidynamic compaction, microstructure, mesocomposite, nanocomposite
Copyright © 2009 ISPMS, Siberian Branch of the RAS. Published by Elsevier BV. All rights reserved.
* Corresponding author
Prof. Mariya P. Bondar, e-mail: bond@hydro.nsc.ru
1. Introduction
The principles of physical mesomechanics [1] can be
effectively used for designing heterogeneous materials with
high mechanical characteristics (hardness, strength, wear
and heat resistance). When designing heterogeneous mate-
rials and studying their properties much attention is paid to
internal interfaces.
Development of materials with high wear resistance ope-
rating under high temperatures and stresses are of particular
importance. Particle reinforced alloys well fit these require-
ments. Such alloys show the noticeable effect of reinfor-
cement due to the presence of a thin precipitated disperse
phase. Heat resistance of particle reinforced alloys depends
on stability of the reinforcing phase. Alloys reinforced by
oxide or boride particles are most structurally stable.
Reinforcing particles act as barries for the dislocation
motion, which induces the shear stress increase. According
to Orowans theory, the yield stress can be represented as
s 1
, WW W where
s
W is the yield stress of the matrix and
1
W is the additional stress necessary for dislocation bending
around obstacles. Orowans theory developed by Fisher,
Hart, Pry [2] and Ashby [3] takes into account the matrix
reinforcement:
12
s m
0.24 ( ) , / > B= @ W where
m
/ is the
matrix shear modulus, f is the volume fraction of precipi-
tates, a is the shear deformation along the primary slip
system, d is the particle diameter and b is the absolute value
of the Burgers vector. Evidently at a given volume fraction
of the reinforcing phase the property variation of alloys is
mainly related to a dispersion degree of precipitates deter-
mining the average interparticle distance.
Internally oxidized copper alloys have been earlier stu-
died in papers [4, 5]. They show advantages of these alloys
as compared to ordinary copper alloys. However, production
of these materials meets the constraint on the strength in-
crease depending on the volume fraction of constant-size
particles. This is governed by the kinetics of internal oxida-
tion. An increase in the oxidizing element content above a
certain value leads to coarsening of precipitate particles and
consequently to the yield stress decrease.
M.P. Bondar, M.A. Korchagin, E.S. Obodovskii et al. / Physical Mesomechanics 12 12 (2009) 94`100 94