Shock reactive synthesis of TiAl

The shock reactive synthesis (SRS) processing was developed to yield bulk solid titanium aluminides in a non-equilibrium phase structure. From blended element powder compacts with a composition of Ti50A150, TiAl is directly synthesized without porosities. The shock-induced reactions can be macroscopically described by SRS-diagram, and the effect of the detonation condition and the green compact porosity on the constituent phases and microstructure of synthesized materials are also discussed on this diagram. In the reactive zone of this diagram, the abundance ratio of α₂ to γ in the α₂γ two-phase synthesized materials can be controlled from the equilibrium ratio to the α₂ single phase by increasing the detonation velocity and/or the porosity of compact. By using multi-layered samples with a sandwich structure of Ti and Al porous discs, the fundamental mechanism of shock-induced reactions can be investigated to clarify the role of high speed mixing and homogenization of titanium and aluminum in the reaction process at the passage of shock wave.