Elastic constants and thermal expansion of single crystal γ-TiAl from 300 to 750 K1

The six independent elastic constants of a γ-TiAl (Ti44Al56) single crystal have been measured for the first time from room temperature to 750 K using a resonant ultrasound spectroscopy technique. The values of C12 and C13 are virtually temperature independent, whereas C11, C33, C44, and C66 decrease between 6 and 9% from 300 to 750 K. The two independent linear thermal expansion coefficients α1 (along [100] direction) and α2 (along [001] direction) of single crystal γ-TiAl have been measured from 4 to 750 K using two different apparatus. The elastic constants have been corrected for the effect of thermal expansion, and the corrected Cij have been used to calculate the Youngʹs and shear moduli along various crystal directions. The elastic constants and moduli values have also been extrapolated to 1273 K. Finally, the elastic anisotropy has also been calculated as a function of temperature.