Autor:	I. Azcona, José M. Sánchez, F. Castro
Rok vydání:	2000
Předmět:	Austenite Toughness Materials science Mechanical Engineering Metallurgy Cermet chemistry.chemical_compound Brittleness Fracture toughness chemistry Mechanics of Materials Tungsten carbide Powder metallurgy General Materials Science Titanium diboride
Zdroj:	Journal of Materials Science. 35:9-14
ISSN:	0022-2461
DOI:	10.1023/a:1004763709854
Popis:	Mechanical properties of titanium diboride (TiB2) cermets critically depend on the composition of the binder phase. Both, fracture toughness and hardness are substantially increased by avoiding the formation of extremely brittle secondary borides which form during sintering by chemical reactions between TiB2 and the metallic additives. Fractographic observations of TiB2 cermets without secondary borides show the presence of ductile ligaments of the binder phase bridging the advancing crack tip. The powder metallurgy processing route applied to these materials allows modification of the binder phase structure from the ferritic iron-aluminium phase to Fe-Ni-Al austenite by changing the aluminium content of the powder mixtures. The highest toughness values have been obtained for the TiB2 cermets with an austenitic binder phase. X-ray diffraction analyses of the fracture surfaces of such samples show that the binder phase is metastable exhibiting stress induced martensitic transformation during fracture. This new family of materials presents an outstanding combination of hardness and toughness, comparable to those obtained with commercial grades of tungsten carbide (WC) hardmetals.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::505559fa59357e9279a916079804fec3 https://doi.org/10.1023/a:1004763709854 Zobrazit plný text záznamu Full text from SpringerLink