The effect of heat treatments on the microstructural stability of the intermetallic Ti-46.5Al-2W-0.5Si

Citation
I. Gil et al., The effect of heat treatments on the microstructural stability of the intermetallic Ti-46.5Al-2W-0.5Si, INTERMETALL, 9(5), 2001, pp. 373-385
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science","Material Science & Engineering
Journal title
INTERMETALLICS
ISSN journal
0966-9795 → ACNP
Volume
9
Issue
5
Year of publication
2001
Pages
373 - 385
Database
ISI
SICI code
0966-9795(200105)9:5<373:TEOHTO>2.0.ZU;2-D
Abstract
The effect of heat treatment on the microstructure of a gamma -based TiAl a lloy containing W and Si has been studied. The starring microstructure of a cast and heat-treated commercial gamma -based TiAl alloy component has bee n interpreted in terms of the phase changes between an a-Ti,Al structure at high temperatures, an alpha (3) + gamma decomposition at intermediate temp eratures, and the change to a B2 + gamma microstructure at lower temperatur es. The fine lamellar microstructure produced after fairly rapid cooling fr om high temperatures consists mostly of alpha (2) + gamma lamellae but tran sforms surprisingly rapidly at lower temperatures (950-1000 degreesC) into a globular structure composed of a gamma matrix and equiaxed particles of B 2 phase, occasionally of remnant alpha (2) phase or of Ti5Si3 silicide. Mat erial strength, as assessed by microhardness, fails rapidly as the initial alpha (2) + gamma lamellar microstructure transforms to the globular one be coming an essentially gamma + B2 mixture. (C) 2001 Elsevier Science Ltd. Al l rights reserved.