Abstract
The elastic stiffnesses of Al-Cu alloys containing columnar crystals were determined from the ultrasonic wave velocities. Ultrasonic testing was done on the alloys subjected to different conditions of casting, solution treatment, and aging preceded by solution treatment. The stiffnesses (A, C and F) relating to normal strain were more influenced by the solute content and the heat treatment than the stiffnesses (L and N) relating to shear strain. The decrease of the stiffnesses A and C after the solution treatment was explained by the dissolution of the eutectic phase occurred in the cast structure. The influence of the solute segregation on the stiffnesses was analyzed to be negligible for a simple model.
