National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
The Role of Microstructure in Fracture Resistence Control of TiAl Based Intermetallics
Dlouhý, Ivo ; Haga, H. ; Chlup, Zdeněk ; Hadraba, Hynek ; Hasegawa, M. ; Fukutomi, H.
The analysis of the role of microstructure in fracture performance of TiAl intermetalics at room and elevated temperatures has been carried out. For Ti-46Al-0.7Cr-0.1Si-7Nb-0.2Ni alloy different regimes of thermal and thermal-mechanical treatment were applied enabling to control substantially microstructural parameters. Attention was paid to grain (colony) size effect, effect of lamellas thickness and morphology and, in addition, to β-phase effect. For separate treatment regimes the flexural strength and fracture toughness were evaluated in addition to microstructural parameters. Fractographic analysis enabled to evaluate fracture micromechanisms; development of shear ligament toughening was observed in almost all cases. This is the key mechanism controlling the fracture behaviour. Based on findings obtained key aspects of the effect of separate microstructural components have been discussed.
Lomová houževnatost a mechanismy porušování intermetalika na bázi TiAl
Dlouhý, Ivo ; Chlup, Zdeněk ; Hadraba, Hynek ; Kozák, Vladislav
The paper is focused on the analysis of the role of microstructure in fracture performance of TiAl intermetalics at room and elevated temperatures. Tensile properties, flexural strength and fracture toughness have been evaluated for Ti-40Al-2Cr-2Nb-1B and Ti-46Al-0,7Cr-0,1Si-7Nb-0,2Ni alloys. Positive Nb effect on fracture resistance was found; fracture toughness of the high Nb alloy was increased at contemporary increase of tensile and flexural strength. Fracture surfaces were evaluated using scanning electron microscopy showing the key role of mechanical twinning in deformation of both alloys. As a governing mechanism of the crack initiation a microcrack nucleation at boundaries between -TiAl grains was confirmed. Based on findings obtained key aspects of the effect of separate microstructural components have been discussed. Summary of toughening effects acting in this group of intermetalics has been provided.

Interested in being notified about new results for this query?
Subscribe to the RSS feed.