Elastic properties of tantalum carbide (TaC)

Elastic properties of TaC have been investigated experimentally and by model calculations. The elastic stiffness coefficients c11=597(11) GPa and c44=153(2) GPa were determined on a (100)-oriented disc-shaped monocrystal at room temperature using a plane-wave ultrasound method. The corresponding theoretical values (c11=621(3), c44=166.8(3) GPa) agree within 4 and 8%, respectively. Therefore, we are confident that the predicted value for c12 is equally accurate, and this allows the prediction of the Bulk and Young's moduli and the Poisson ratio. Data published earlier are critically reviewed and predictions concerning the possibility to synthesize extremely incompressible carbides are made.