Microstructure and mechanical properties of Al-assisted sintered Fe/Al2O3 cermets

• Published in: Journal of the European Ceramic Society 1999-01, Vol.19 (13-14), p.2455-2463
• Main Authors: SCHICKER, S, ERNY, T, GARCIA, D. E, JANSSEN, R, CLAUSSEN, N
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Fractures; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Powder metallurgy. Composite materials; Production techniques; Sintered metals and alloys. Pseudo alloys. Cermets
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/s0955-2219(99)00107-7

Fe/Al2O3 composites with metal contents between 23 and 35 vol% were fabricated via Al-assisted pressureless reaction sintering. The effect of variation of oxygen partial pressure during sintering on phase development, microstructure and mechanical properties was investigated. The formation of the spinel phase FeO.Al2O3 occurred at elevated temperatures if the oxygen partial pressure during sintering exceeded a critical value. Microstructural observations and image analysis revealed that the composites exhibit a microstructure with the ceramic and the metal phase forming interpenetrating networks. The fracture toughness increased with increasing metal content and strongly depended on the phase content of the sintered specimens. In composites containing a small amount of FeO.Al2O3, the maximum toughness was 7.1 MPa.m1/2 was achieved by avoiding spinel formation to obtain composites consisting only of Fe and Al2O3. 32 refs.