Abstract: The paper presents results of molecular dynamic (MD) simulations in 3D bcc iron
crystals with edge pre-existing cracks (001) and (110)  (crack plane/crack front) loaded
uni-axially in tension mode I at temperature of 300 K. The iron crystals in MD have the same
orientation and similar geometry as in our recent fracture tests performed at room temperature on
iron (3wt.%Si) single crystals .
Abstract: Atomic mechanisms of the beginning of plastic deformation and failure initiation in nanoparticles of
b.c.c. transition metals are presented in this report. It is shown that strength level of nanoparticles of
b.c.c. transition metals is pre-determined by the lattice instability within the local region of the
crystal. At uniaxial tension even at low temperatures perfect crystal becomes unstable to shear
(„orthorhombic“ path), i.e. local shear instability is the main mechanism of stress relaxation in
nanoparticles of b.c.c. metals. Specific features of local instability of nanoparticle under hydrostatic
tension are considered. A model of the temperature dependence of strength is offered. It is shown
that nanoparticle strength decreases as square root function of temperature with temperature growth.
Just this is essential difference of the temperature dependence of nanoparticle strength from the
same for “ordinary” single- and polycrystals.
Abstract: The parameters of exponential many-body Finnis-Sinclair potentials corresponding to
qualitatively different crystal lattice stability were selected and their behaviour was studied.
Furthermore, a model with pairwise Lennard-Jones potential was also considered. The attention was
paid to the stability of different crystal structures and the properties of simple interfaces such as
stacking faults and twin boundaries were investigated.
Abstract: Influence of biaxial stress applied perpendicularly to the  loading axis on the tensile
stress-strain response is studied from first principles. Crystals of four cubic metals Mo, W, Ir and
Au were selected as particular case studies. The results obtained show that, within a limited range of
biaxial stresses, the tensile stress increases almost linearly with increasing transverse biaxial stress.
The factor that expresses the slope of the linear function changes with applied tensile strain.
A region of tensile stability of cubic crystals is also discussed.
Abstract: The ideal tensile strength along the  direction in the Fe3Al and Ni3Al intermetallic
compounds with the D03 structure has been calculated from the first principles using the fullpotential
linearized augmented plane-wave method (FP LAPW) within the density functional theory
(DFT). The strains corresponding to the maximum sustainable stresses in both materials were
determined and compared. The behavior of atomic magnetic moments as a function of strain was
analyzed. The tensile test simulations have been theoretically simulated employing both the local
density approximation (LDA) and generalized gradient approximation (GGA) for the exchangecorrelation
Abstract: A Monte Carlo algorithm for single-phase normal grain growth has been implemented,
which allows one to simulate and observe the temporal development of large grain microstructures
in three dimensions. The relaxation process to the self-similar coarsening regime has been studied
by following the temporal development of quantities like the average grain size, the standard
deviation of the grain sizes and topological correlations.
Abstract: The mechanical properties and deformation behaviour of magnesium alloys are
significantly influenced by the testing temperature, texture and grain size. The paper gives an
overview on the influence of the grain size on the mechanical properties of Mg and Mg-2Al alloys
at various temperatures. The yield stress and the fracture stress increase with decreasing grain size.
It was shown that the elongation to fracture increases with inverse square root of grain size. The
effect of grain size on the tensile strength and the elongation to fracture is influenced by the testing
temperature. The observed grain size dependence of the elongation to fracture is explained by the
activity of non-basal slip systems.
Abstract: The combined effect of cyclic thermal shocks and static tensile loading is investigated, in a 304L
stainless steel. During these experiments, the stress state in the cylindrical specimen walls is nearly
equi-biaxial (σZZ ≈ σθθ). In dislocation dynamics (DD) simulations carried out with σZZ = σθθ, the
predominant slip directions b are nearly aligned with the free surface normal vector n, regardless of
their associated activation ratio (A.R.). This effect is related to the "surface connected volume"
(SCV) of the predominant slip systems. Hence, surface grains with n = <110> possess "large SCV
slip systems" and therefore, constitute preferential sites for micro-crack initiation in thermal fatigue.
During the tests, a marked effect of the superimposed static tensile loading (or mean stress) is also
noted. This effect is explained with the help of DD simulations performed with a positive mean
stress: slip irreversibility in the individual persistent slip bands systematically augments with
increasing mean stress.
Abstract: This paper deals with an experimental investigation of the effect of various microdefects
induced by equal-channel angular pressing (ECAP) on mechanical and creep properties of ultrafinegrained
pure aluminium, an Al-0.2%Sc alloy and copper.