M. H. Loretto, University of Birmingham, Birmingham, United Kingdom; H. Jiang, H. Saage, D. Hu, X. Wu, IRC in Materials Processing, University of Birmingham, Birmingham, United Kingdom
The factors that control the nucleation and growth of massive gamma in TiAl-based alloys are reviewed with the aim of understanding the role that alloy composition has on the kinetics of the massive transformation. It is accepted that the growth of massive gamma, which involves individual atomic jumps across the interface between the alpha and the massive gamma, takes place far more rapidly than the growth of the other transformation products, lamellae, feathery and Widmenstatten because these require long distance diffusion. The situation concerning the factors which control the rate of nucleation is less clear and recent work aimed at understanding nucleation will be presented.
Summary: The factors that control the nucleation and growth of massive gamma in TiAl-based alloys are reviewed with the aim of understanding the role that alloy composition has on the kinetics of the massive transformation. It is accepted that the growth of massive gamma, which involves individual atomic jumps across the interface between the alpha and the massive gamma, takes place far more rapidly than the growth of the other transformation products, lamellae, feathery and Widmenstatten because these require long distance diffusion. The situation concerning the factors which control the rate of nucleation is less clear and recent work aimed at understanding nucleation will be presented.
