Cyclic degradation of titanium-tantalum high-temperature shape memory alloys - the role of dislocation activity and chemical decomposition
|authors:||T. Niendorf, P. Krooß, C. Somsen, R. Rynko, A. Paulsen, E. Batyrshina, J. Frenzel, G. Eggeler, H.J. Maier|
|publication:||Functional Materials Letters|
Titanium-tantalum shape memory alloys are promising candidates for actuator applications at elevated temperatures. They may even succeed in substituting ternary nickel-titanium high temperature shape memory alloys, which are either extremely expensive or difficult to form. However, titanium-tantalum alloys show rapid functional and structural degradation under cyclic thermo-mechanical loading. The current work reveals that degradation is not only governed by the evolution of the ω-phase. Dislocation processes and chemical deposition of the matrix at grain boundaries also play a major role.