Advances in the fundamental understanding for designing engineering gamma TiAl alloys*

Abstract

Phase transformations and microstructural evolution observed in various γ‐TiAl based alloys are discussed. The mechanical properties are summarized and analyzed in duplex as well as fully‐lamellar materials over a wide range of grain sizes. From the structure‐property relationships, a generalization is made on the desired microstructural features which will result in significant improvements in balanced or specific properties. Further property enhancement, especially in creep resistance achieved by microalloying with carbon and Si, is also discussed. On the basis of the accumulated knowledge and data, the next‐generation TiAl alloy system for higher temperature use is formulated.