Published online by Cambridge University Press: 10 February 2011
A new generation of wrought γ-TiAl alloys having a good balance of properties at both low and high temperatures has recently been developed. Addition of light elements (C, Si) to the base alloy of this system (K5 material) has been shown to increase the creep strength of the material significantly. The microstructure of the materials with superior creep performance was found to consist of wellaligned rows of fine precipitates, delineating partially dissolved α2 laths. These precipitates were found to interact strongly with dislocation structures. This paper studies the mechanisms for α2 dissolution and fine particle precipitation in annealed samples of the K5 series alloys. Microstructural design issues that would allow for optimization of the particular strengthening mechanism will also be discussed.