Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surface Morphology and Phase Stability of Titanium Foils Irradiated by
  136 MeV 136Xe   A stack of titanium foils was irradiated with 136 MeV 136Xe to study
microstructure damage and phase stability of titanium upon irradiation. X- ray
diffraction, scanning electron microscopy/energy dispersive spectroscopy and
atomic force microscopy were used to study the resulting microstructure damage
and phase stability of titanium. We observed the phase transfor- mation of
polycrystalline titanium from alpha-Ti (hexagonally closed packed (hcp)) to
face centered cubic (fcc) after irradiation with 2.2 x 1015 ions/cm2.
Irradiation of Ti with 1.8 x 1014-2.2 x 1015 ions/cm2 resulted in the forma-
tion of voids, hillocks, dislocation loops, dislocation lines, as well as
polygonal ridge networks.

10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math