Instead of conventional grain-refinement treatments for improving the ductility of fully lamellar TiAl alloys, multiorientational, lamellar, subcolony refinement with good ductility has been achieved simply by using an electric-current pulse treatment. The microstructural refinement mechanism is attributed to the transformation on heating of γ laths in the prior large-grain lamellar structure to Widmanstätten α in several orientations, which on subsequent cooling forms lamellar structure colonies in multiple orientations. This kind of refined multiple-colony lamellar structure was found to enhance the ductility of the TiAl alloy.
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This research was supported by the National Nature Science Foundation of China, Grant No. 50571100, the Hundred Talents Project funded by the Chinese Academy of Sciences, and the Special Funds for the Major State Basic Research Project of China (No. 2002CB613503).
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Cui, J., Sui, M., Cui, Y. et al. Ductile TiAl alloy with a Widmanstätten lamellar structure formed by rapid heating. Journal of Materials Research 23, 949–953 (2008). https://doi.org/10.1557/jmr.2008.0138