Revisiting the mechanical behavior of alumina/silicon carbide nanocomposites

✍ Scribed by J Pérez-Rigueiro; J.Y Pastor; J Llorca; M Elices; P Miranzo; J.S Moya

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 979 KB
• Volume: 46
• Category: Article
• ISSN: 1359-6454
• DOI: 10.1016/s1359-6454(98)00193-1

✦ Synopsis

AbstractÐThe microstructure and mechanical properties of three Al 2 O 3 /SiC nanocomposites containing dierent average particle size (200 and 800 nm) and volume fraction (5 and 20%) were studied and compared with three reference aluminas. The microstructural analyses revealed that the smaller nanoparticles were distributed within the grains, while the larger ones were usually found at the grain boundaries. The dispersion of the nanoparticles led to a signi®cant reduction in the grain size, which decreased as the particle volume fraction increased or the particle size decreased. In general, the nanocomposite ¯exure strength was slightly higher than that of the monolithic aluminas whereas the fracture toughness measured through the single-edge V-notched beam technique was slightly lower. The mechanical properties were not signi®cantly aected by either the nanoparticle fraction (5 or 20%) or size (200 and 800 nm). The fracture mode changed from intergranular in the monolithic aluminas to transgranular in the composites. The increase in the nanocomposite strength was found to be a result of the reduction in the critical ¯aw size provided by the dispersion of nanoparticles.