ELASTIC-CONSTANTS AND THERMAL-EXPANSION OF SINGLE-CRYSTAL GAMMA-TIAL FROM 300 TO 750 K

The six independent elastic constants of a gamma-TiAl (Ti44Al56) singl e crystal have been measured for the first time from room temperature to 750 K using a resonant ultrasound spectroscopy technique. The value s of C-12 and C-13 are virtually temperature independent, whereas C-11 , C-33, C-44, and C-66 decrease between 6 and 9% from 300 to 750 K, Th e two independent linear thermal expansion coefficients alpha(1) (alon g [100] direction) and alpha(2) (along [001] direction) of single crys tal gamma-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 C-ij have been used to calculate the Young's and shear moduli along various crystal directions. The el astic constants and moduli values have also been extrapolated to 1273 K. Finally, the elastic anisotropy has also been calculated as a funct ion of temperature. (C) 1997 Elsevier Science S.A.