Several mesoscale models have been developed to consider
a number of mechanical properties and microstructures
of Ti-V approximants to Gum Metal and steels from the atomistic scale.
In Gum Metal, the relationships between phonon properties
and phase stabilities are studied. Our results show that
it is possible to design a BCC (&beta-phase)
alloy that deforms near the ideal strength,
while maintaining structural stability
with respect to the formation of the &omega
and &alpha'' phases. Theoretical diffraction patterns reveal
the role of the soft N-point phonon
and the BCC-to-HCP transformation
path in post-deformation samples. The total energies
of the path explain the formation of the giant faults
and nano shearbands in Gum Metal.
In the study of steels, we focus on the carbon-solute dislocation
interactions. The analysis covers the Eshelby's model of point defects
and first principles calculations. It is argued that the effects
of chemistry and magnetism, omitted in the elasticity model,
do not make major contributions to the segregation energy.
The predicted solute atmospheres are in good agreement
with atom probe measurements.