Mechanical behavior and lattice reorientation during tensile deformation of Al-4%Cu-0.1%Fe single crystals

Abstract

The mechanical behavior and the changes in the orientation of Al-4%Cu-0.1%Fe single crystals during tensile deformation were investigated at room temperature. Tensile tests were performed after three different heat treatment conditions: quenched from solid solution, fully hardened and overaged. For the quenched and fully hardened crystals, tensile axis rotation occurred as a consequence of single slip on the primary system (111)[ 1 01]. In the quenched crystals, double slip was activated in a limited region of the gage length resulting in a typical double wedge previous to failure. Rotation of the tensile axis along the symmetry boundary could be detected in this highly deformed region of the crystals. In the fully hardened condition, however, double slip was not observed and a strong shear band prior to fracture was developed. The overshooting observed never exceeded 3°. The difference in ductility and strain hardening rate observed between the quenched and fully hardened crystals is attributed to the activation of secondary slip systems that interact with the primary system. In the overaged condition, the reorientation of the tensile axes resemble those observed in polycrystalline samples. This behavior and the high hardening rate observed in the early stages of deformation are interpreted in terms of the quasi-simultaneous activation of several slip systems which is in agreement with previous investigations.