Pressure casting of a zirconia-toughened alumina fiber-reinforced NiAl composite

The Physical and Mechanical Metallurgy of NiAl

“…Possible processing routes include the powder-cloth process (Pickens et al 1989), foil/fiber or tape casting, thermal spray processes (Kern, Kaczmarek, and Janczak 1992), and pressure casting (Nourbakhsh et al 1991). Of these techniques, powder-cloth has been used most often for generating NiAI matrix composites for mechanical property characterization.…”

Strength degradation of sapphire fibers during pressure casting of a sapphire-reinforced Ni-base superalloy

“…Extensive chemical attack of polycrystalline as well as single crystal alumina fibers also has been noted in pressure-cast and powder-processed Fe-and Ni-base intermetallic-matrix composites. [7,8] The degradation of strength of single crystal sapphire (SA-PHIKON Inc.) fibers in ''powder-cloth'' processed FeCrAlY, FeCrAl, Cr, FeAl, and NiAl matrix composites is in the range of 45 to 60 pct, [5,6] whereas strength degradation in pressure-cast Ni 3 Al-Ti matrix composites is reported to be 67 pct. [8] The distribution of fiber strength in these composites was reported to be consistent with Weibull statistics.…”

“…IT is well known that solid-state techniques [1][2][3][4][5][6] of fabricating high-temperature fiber-reinforced superalloys and intermetallics suffer from the problems of interface contamination from binder residues and oxides on metal powders. Liquid-phase fabrication using pressure casting of fiber-reinforced Fe-and Ni-base intermetallics [7,8] offers flexibility in designing matrix and interface structures. Improvement in wettability by alloying [9] or application of pressure [7,8] is required to manufacture structurally viable defect-free composite castings.…”

“…Liquid-phase fabrication using pressure casting of fiber-reinforced Fe-and Ni-base intermetallics [7,8] offers flexibility in designing matrix and interface structures. Improvement in wettability by alloying [9] or application of pressure [7,8] is required to manufacture structurally viable defect-free composite castings. Relatively little work has been reported in the literature on liquid-phase fabrication of ceramic fiberreinforced superalloys.…”

Interface response to solidification in sapphire-reinforced Ni-base composites

“…Additionally, substantial mechanical damage to the fibers could be caused during the solid-state consolidation. Liquid-phase composite fabrication techniques such as vacuum-and pressure casting [9][10][11][12], and directional solidification [13][14][15][16][17][18][19][20] have been employed to synthesize intermetallic-matrix composites such as NiAl, Ni 3 Al, TiAl and FeAl reinforced with a variety of alumina fibers (DuPont's fibers FP and PRD166, Saphikon's single crystal sapphire, and others). Likewise, high-temperature superalloys also have been reinforced with both metals (tungsten fiber [21]) and ceramics (Al 2 O 3 fiber [22]).…”