Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Alloying-related trends from first principles: An application to the
  Ti--Al--X--N system   Tailoring and improving material properties by alloying is a long-known and
used concept. Recent research has demonstrated the potential of ab initio
calculations in understanding the material properties at the nanoscale. Here we
present a systematic overview of alloying trends when early-transition metals
(Y, Zr, Nb, Hf, Ta) are added in the Ti$_{1-x}$Al$_x$N system, routinely used
as a protective hard coating. The alloy lattice parameters tend to be larger
than the corresponding linearised Vegard's estimation, with the largest
deviation more than 2.5% obtained for Y$_{0.5}$Al$_{0.5}$N. The chemical
strengthening is most pronounced for Ta and Nb, although also causing smallest
elastic distortions of the lattice due to their atomic radii being comparable
with Ti and Al. This is further supported by the analysis of the electronic
density of states. Finally, mixing enthalpy as a measure of the driving force
for decomposition into the stable constituents, is enhanced by adding Y, Zr and
Nb, suggesting that the onset of spinodal decomposition will appear in these
cases for lower thermal loads than for Hf and Ta alloyed Ti$_{1-x}$Al$_x$N.

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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: q-alg
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The categories of this paper are: alg-geom
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: plasm-ph
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The categories of this paper are: math
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The categories of this paper are: hep-th
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The categories of this paper are: hep-lat