%0 journal article
%@ 0925-8388
%A Gabrisch, H., Janovská, M., Rackel, M.W., Pyczak, F., Stark, A.

%D 2023
%J Journal of Alloys and Compounds

%P 167578 
%R doi:10.1016/j.jallcom.2022.167578
%T Impact of microstructure on elastic properties in the alloy Ti-42Al-8.5 Nb
%U https://doi.org/10.1016/j.jallcom.2022.167578
 
%X The microstructure of a γ-TiAl alloy containing niobium undergoes continuous transformations during annealing at 550 °C. These take place within the α2-phase of lamellar (α2 +γ) colonies. We have characterized these changes by transmission electron microscopy and made a correlation to the elastic constants determined by resonant ultrasonic spectroscopy during in-situ annealing at the same temperature. The results show a continuous increase of the E-modulus. This can be attributed to elastic strains acting within α2 lamellae as a result of lattice transformations. After 5000 h, a thermodynamic equilibrium was established with equal fractions of α2-phase and O-phase that differ only in lattice symmetry and Nb content. Generally, the presence of O-phase should contribute to lower elastic moduli, however in the present case the evolving microstructural characteristics were responsible for the observed increase in the E-modulus.