Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evaluation of the tribological properties of metal matrix composite
  materials (MMCs) obtained by additive manufacturing using selective laser
  melting (SLM)   The mechanical and tribological properties of steel matrix composites (316L
stainless steel reinforced with Cr3C2 ceramic particles) were investigated. The
steel matrix composites (SMC) with three reinforcing percentages (3, 6, and 9
wt.%) were manufactured by Additive Manufacturing technologies (SLM: Selective
Laser Melting). The wear behaviour was studied by using a pin-on-disk wear test
at room temperature. The worn surface was analysed using Scanning Electron
Microscopy (SEM). The results indicated that the friction coefficient does not
have a clear tendency or direct correlation with the reinforcement variation
while the wear rate decreases with increasing content of reinforcement. The
better properties combination were achieved with 6 wt.% of reinforcement.

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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: stat
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph
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The categories of this paper are: cs
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The categories of this paper are: astro-ph
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ex
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The categories of this paper are: q-bio
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess