Morphology and growth kinetics of discontinuous coarsening in fully lamellar Ti-44 Al (at%) alloy

Journal Article · Fri Oct 31 23:00:00 EST 1997 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(97)00139-0· OSTI ID:589988

Mitao, S; Bendersky, L A ^[1]

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1. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Metallurgy Div.

The morphology of discontinuous coarsening in the Ti{sub 3}Al({alpha}{sub 2})/TiAl({gamma}) fully lamellar Ti-44 at.% Al alloy has been studied. Three types of morphology were observed in discontinuously coarsened lamellar structures (secondary lamellae). Type-(I) lamellae have the low energy habit plane as their lamellar interfaces, and have the same lamellar direction as the original primary lamellae. Type-(II) lamellae have the same crystallographic orientation of the {alpha}{sub 2} plates as that in the original primary lamellae, but have a different lamellar direction from the original primary lamellae, and have irregular faceted lamellar interfaces. Type-(III) lamellae have a different lamellar direction and a different crystallographic orientation of the {alpha}{sub 2} plates from that in the original primary lamellae, but have the low energy habit plane as their lamellar interfaces. The growth kinetics of these three types of lamellae are discussed by modifying the Livingston and Cahn treatment in order to obtain the dependence of the secondary lamellar morphologies on misorientation between the penetrated primary lamellae, the advancing secondary lamellae and the lamellar colony boundaries.

• OSTI ID: 589988
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 11 Vol. 45; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
GRAIN GROWTH
GRAIN ORIENTATION
LAMELLAE
MICROSTRUCTURE
TITANIUM BASE ALLOYS