Novel Reaction-Based Processing of Co-Continuous Ceramic-Metal Composites

• Published in: Key engineering materials 1996-11, Vol.127-131, p.73-80
• Main Authors: Claussen, N., Wagner, Francis, García, D.E., Bruhn, J., Schicker, S., Janßen, Rolf
• Format: Article
• Language: English
• ISSN: 1013-9826; 1662-9795; 1662-9795
• DOI: 10.4028/www.scientific.net/KEM.127-131.73

Various ceramic-metal composites have been manufactured by either reaction sintering compacts of intensively milled powder mixtures or by reaction infiltration of porous oxide precursor bodies containing Fe sub 2 O sub 3 , ZrO sub 2 , TiO sub 2 , NiO, Nb sub 2 O sub 5 , etc. During the carefully controlled heating cycle in vacuum, the oxide reduction by Al to form the respective aluminide or metal aluminide alloys proceeds at relatively low temperatures. By adding Al sub 2 O sub 3 to the starting mixture, the final composition of such Al2O34-aluminide alloys (3A) can be adjusted in a wide compositional range. At metal or intermetallic volume fractions > 20%, both phases are continuous, hence exhibiting an interpenetrating network similar to that of products of directed molten metal oxidation or reactive metal penetration processes. In this paper, systems based on TiAl, FeAl and NbAl sub 3 are emphasized, though other 3A composites have also been investigaated. Preliminary 4-point bend strengths of approx700 MPa in the Al sub 2 O sub 3 -FeAl system and approx500 in the Al sub 2 O sub 3 -TiAl system have been obtained. The most attractive aspects of 3A composites are their low-cost manufacturability, low specific weight, refractoriness and excellent oxidation and corrosion resistance.