XRD and XPS studies of surface MMC layers developed by laser alloying Ti6Al4V using a combination of a dilute nitrogen environment and SiC powder

M.S. Selamat, L.M. Watson, T.N. Baker

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Using a continuous-wave CO2 laser, surface engineering of a Ti-6Al-4V alloy through a combined treatment of laser nitriding and SiC preplacement was undertaken. Under spinning laser beam conditions, a surface alloyed / metal matrix composite (MMC) layer over 300μm in depth and 24mm wide was produced in the alloy by the overlapping of 12 tracks. Microstructural and chemical changes were studied as a function of (a) depth in the laser formed composite layer and (b) of the track position. Using X- ray diffraction (XRD) and X-ray photospectrographic (XPS) techniques, it was shown that the composite layer contained a complex microstructure which changed with depth. At the surface, a non-stoichiometric, cubic TiNx solid solution ( possibly a carbonitride) containing C and Si , where x ≈ 0.65-0.8, was prominent, but was replaced by α′-Ti with increasing depth to 300μm. TiC phase was also identified, and the presence of TiN0.3 and Ti5Si3 phases considered a distinct possibility. 1
Original languageEnglish
Pages (from-to)724-736
Number of pages12
JournalSurface and Coatings Technology
Issue number3-4
Publication statusPublished - Oct 2006


  • laser surface engineering
  • titanium alloy
  • X-ray diffraction
  • photoelectron spectroscopy
  • lattice parameters

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