Influence of crystallographic orientation on cyclic strain-hardening behaviour of copper single crystals

The cyclic strain-hardening behaviour of copper single crystals with variou s slip orientations is considered systematically. It is shown that the crys tallographic orientation has a strong effect on the cyclic hardening behavi ours of double- and multiple-slip-oriented copper single crystals. The init ial cyclic hardening of differently oriented copper single crystals is main ly dependent on the modes and intensities of dislocation interactions betwe en slip systems operating in the crystal, as well as on the possibility of cross-slip. A distinctive strain burst phenomenon has been frequently obser ved in the very early stage of cyclic hardening for critical double-slip-or iented crystals. A secondary cyclic hardening stage occurs readily late in cyclic deformation of coplanar double-slip-oriented crystals.