Processing of an α-2 aluminide alloy, Ti-24Al-11Nb

Abstract

Compressive stress-strain curves have been generated over a range of temperatures (900–1100°C and strain rates (0.001–100 s⁻¹) for two starting structures consisting of lath α₂ and equiaxed α₂ in a Ti-24Al-11Nb alloy. The data from these tests have been analysed in terms of a dynamic model for processing. The results define domains of strain rate and temperature in which dynamic recrystallization of α₂ occurs for both starting structures. The rate controlling process for dynamic recrystallization is suggested to be cross-slip in the α₂ phase. A region of processing instability has also been defined within which shear bands form in the lath structure. Recrystallization of the β phase is shown to occur for different combinations of strain rate and temperature from those in which the α₂ phase recrystallizes dynamically.