Original title: Lomová houževnatost a mechanismy porušování u intermetalika na bázi TiAl
Translated title: Fracture toughness and damage mechanisms of intermetalic based on TiAl
Authors: Dlouhý, Ivo ; Chlup, Zdeněk ; Hadraba, Hynek ; Kozák, Vladislav
Document type: Papers
Conference/Event: Porušování a design materiálu, Brno (CZ), 2007-10-31 / 2007-11-01
Year: 2007
Language: cze
Abstract: [cze] [eng]
Práce je zaměřena na analýzu role mikrostruktury v lomovém chování TiAl intermetalik a to jak při pokojové, tak i zvýšené teplotě. Byly získány informace o tahových charakteristikách, ohybové pevnosti a lomové houževnatosti u slitin Ti-40Al-2Cr-2Nb-1B a Ti-46Al-0,7Cr-0,1Si-7Nb-0,2Ni. Pozitivní vliv Nb na lomové chování byl nalezen. Lomová houževnatost slitiny s vysokým obsahem Nb rostla stejne jako pevnost v tahu a ohybová pevnost. Jako hlavní mechanismus vzniku trhlin byl stanoven vznik mikrotrhlin na hranicích mezi dvojčaty a gama-TiAl zrny. The paper concentrates on the analysis of the role of microstructure in fracture behaviour of TiAl intermetalics at room and elevated temperatures. Tensile properties, flexural strength and fracture toughness have been evaluated for alloys Ti-40Al-2Cr-2Nb-1B and Ti-46Al-0,7Cr-0,1Si-7Nb-0,2Ni. Positive effect of Nb on fracture resistance has been found; fracture toughness of the high Nb alloy increased at contemporary increase of tensile and flexural strength. Fracture surfaces have been evaluated using scanning electron microscopy showing the key role of mechanical twinning in deformation of both alloys followed. As a governing mechanism of the crack nucleation a microcrack formation at boundaries between mechanical twins and gama-TiAl grains has been confirmed. Extensive development of shear ligament toughening was observed supplying quite good values of fracture toughness in high niobium alloy.
Keywords: Damage mechanisms; Fracture toughness; Intermetalics
Project no.: CEZ:AV0Z20410507 (CEP), GA106/07/0762 (CEP)
Funding provider: GA ČR
Host item entry: Porušování a design materiálu. Sborník semináře Křehký lom 2007, ISBN 978-80-254-0725-7

Institution: Institute of Physics of Materials AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: http://hdl.handle.net/11104/0155837

Permalink: http://www.nusl.cz/ntk/nusl-38247


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Research > Institutes ASCR > Institute of Physics of Materials
Conference materials > Papers