Laser surface processing of B4C-TiB2 eutectic

Anton V. Polotai, John F. Foreman, Elizabeth C. Dickey, Kenneth C. Meinert, Jr.

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

The formation of a directionally solidified non-oxide eutectic surface layer based on the 75mol% B4C and 25mol% TiB2 eutectic composition has been developed using a continuous-wave, high-power, CO2 laser. To prevent the oxidation of nonoxide compounds and to reduce thermal stress formation, an atmospherically controlled furnace capable of back-heating samples up to 1100°C during the laser processing has been employed. The effect of the laser scan rate on the eutectic microstructure formation is investigated. It is found that at relatively slow laser scan rates, ∼2-4mm/s, the formation of a colony-type eutectic microstructure with submicrometer scale features is observed. At higher heating rates up to 42 mm/s, disordered eutectic grains with nanometer-scale TiB2 lamellae form. The dependence of the TiB2 interlamellar spacing on the crystallization rate in the laser solidified B4 C-TiB2 eutectic has the same general trend as in the eutectic produced by a floating zone method. However, this method allows the production of much smaller microstructural length scales, on the order of 100nm, as a consequence of the high crystallization velocity.

Original languageEnglish (US)
Pages (from-to)610-617
Number of pages8
JournalInternational Journal of Applied Ceramic Technology
Volume5
Issue number6
DOIs
StatePublished - Nov 17 2008

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Condensed Matter Physics
  • Marketing
  • Materials Chemistry

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