2,291 research outputs found
Entropy and diffuse scattering: comparison of NbTiVZr and CrMoNbV
The chemical disorder intrinsic to high entropy alloys inevitably creates
diffuse scattering in their x-ray or neutron diffraction patterns. Through
first principles hybrid Monte Carlo/molecular dynamics simulations of two BCC
high entropy alloy forming compounds, CrMoNbV and NbTiVZr, we identify the
contributions of chemical disorder, atomic size and thermal fluctuations to the
diffuse scattering. As a side benefit, we evaluate the reduction in entropy due
to pair correlations within the framework of the cluster variation method.
Finally, we note that the preference of Ti and Zr for HCP structures at low
temperature leads to a mechanical instability reducing the local BCC character
of NbTiVZr, while preserving global BCC symmetry.Comment: Submitted to Met Mat Trans A: TMS Symposium on High Entropy Alloys
(2015
Shapes and textures of ferromagnetic liquid droplets
Theoretical calculations, computer simulations and experiments indicate the
possible existence of a ferromagnetic liquid state. Should such a state exist,
demagnetization effects would force a nontrivial magnetization texture governed
by the shape of the liquid droplet. Since liquid droplets are deformable, the
droplet shape couples to the magnetization texture. This paper solves the joint
shape/texture problem subject to the assumption of cylindrical droplet
symmetry. The shape undergoes a change in topology from spherical to toroidal
as exchange energy grows or surface tension decreases.Comment: 7 pages, 2 figures, submitted to Brazilian Journal of Physic
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