Microstructural characterization of a zirconia-toughened alumina fiber reinforced niobium aluminide composite

S. Nourbakhsh, O. Sahin, W. H. Rhee, H. Margolin

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An NbAl3 + Nb2Al composite reinforced with continuous zirconia-toughened alumina, PRD-166 fibers, was produced by pressure casting and was examined by optical and transmission electron microscopy and energy dispersive spectroscopy. Exposure of the fiber to the molten metal resulted in ZrO2 and Al2O3 grain growth, formation of a thin layer of an amorphous phase on the grain boundaries of Al2O3 and transformation of ZrO2. Preferential Al2O3 grain growth near the surface of the fiber led to the rejection of ZrO2 from this region into the molten metal. In NbAl3 slip occurred by the glide of a<110] superdislocations and tolesser extent by the glide of a pair of <111 + <311] dislocations on the (112) planes and a/2<110] superpartial dislocations on the (001) plane. The operating slip system in Nb2Al was identified as {010)<100]. a<100] dislocations were dissocaited into ax<100] partial dislocations joined together by a stacking fault.

Original languageEnglish (US)
Pages (from-to)285-294
Number of pages10
JournalActa Metallurgica Et Materialia
Issue number2
StatePublished - Feb 1992


ASJC Scopus subject areas

  • Engineering(all)

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