Co-continuous Al/Al2O3 composite produced by liquid displacement reaction: Relationship between microstructure and mechanical behavior

• Published in: Journal of materials science Vol. 38; no. 17; pp. 3567 - 3577
• Main Authors: LA VECCHIA, G. M, BADINI, C, PUPPO, D, D'ERRICO, F
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.09.2003; Springer Nature B.V
• Subjects: Aluminum oxide; Applied sciences; Bend strength; Bonding strength; Ceramic bonding; Cermets, ceramic and refractory composites; Composition effects; Compressive strength; Cross-disciplinary physics: materials science; rheology; Ductile fracture; Electron probe microanalysis; Electron probes; Exact sciences and technology; Materials science; Mechanical properties; Metals. Metallurgy; Microstructure; Other materials; Physics; Porosity; Scanning electron microscopy; Silica glass; Silicon dioxide; Specific materials; Stiffness; Temperature effects; Thermal expansion; Ceramic matrix composite; Electron microprobe; Compression; Porosimetry; Rupture modulus; XRD; Ceramic metal contact; Oxide ceramics; Fabrication; Optical microscopy; Scanning electron microscopy; Mechanical properties; Aluminium; Solid-solid interfaces; Hardness; Experimental study; Silicon additions; Tensile strength; Fracture toughness; Composite materials; Infiltration; Property structure relationship; Liquid displacement; Microstructure; Alumina
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1023/A:1025613011787

Co-continuous 63%Al2O3/37%Al(Si) composite, known as C4 composite, was produced by submersion of silica glass specimens in a molten metal bath. The effect of temperature and composition of the metal bath on the reactive penetration rate was investigated. An infiltration speed exceeding 2 mm/h, increasing with temperature, and suitable for practical applications, was observed above 1100°C. Mechanical properties of C4 specimens were measured, at room temperature, and related to composite microstructure. This latter was investigated by optical and scanning electron microscopy, electron probe microanalysis, X-ray diffraction and porosimetry.The strong interfacial bonds between metal and ceramic resulted in low thermal expansion, high stiffness, and good compression and bending strength. On the contrary, the composite showed a rather poor tensile strength, due to a high ceramic percentage and, partially, to porosity. In spite of the low ductility shown by the investigated composite, the metal network provides a toughening effect, which resulted in a ductile micro-mechanism of fracture, localized in the zones characterized by the presence of the metal matrix.