Modelling of r-curve behaviour in ceramic/metal composites

• Published in: Acta materialia Vol. 46; no. 18; pp. 6381 - 6395
• Main Authors: RADDATZ, O, SCHNEIDER, G. A, CLAUSSEN, N
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Science 20.11.1998
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Fatigue, brittleness, fracture, and cracks; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Metals. Metallurgy; Physics; Aluminium base alloys; Fracture mechanics; Tensile tests; Theoretical study; Mechanical properties; Plastic deformation; Experimental study; Dispersion strengthened metal; Crack opening displacement; Composite materials; Modelling; Alumina; Tenacity
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/S1359-6454(98)00317-6

The incorporation of metals into brittle solids is a successful way to improve their mechanical properties. In the present study, emphasis is placed on the toughness increase of such composites, shown by their R-curve behavior. Although the increased toughness has been experimentally verified in many cases, the theoretical prediction is still a question of concern. The material specific property which controls the toughening effect is the bridging stress relation of the metal reinforcements. In the first part of this paper, a theoretical calculation of this bridging relation from crack opening displacement measurements will be presented. In the second part, a variety of bridging relations will be used to demonstrate their effect on the R-curve behavior of a composite. Both calculations will be verified with experimental results of an Al/Al sub 2 O sub 3 model composite material, where the bridging relation was also measured experimentally.