A study of latent hardening behavior in aluminium single crystals

Parent single crystals were grown from 99.999% pure aluminium using the critical strain-annealing method. The latent hardening is about equal to or a little less than the self-hardening, and the effects of the slip direction, the relative orientation of latent system and the prestrain of primary system on the latent hardening are little. The strain range of the initial transient zone with rapid work-hardening, which occurred in the latent hardening tests, is usually less than the Bauschinger strain. Both the latent hardening and the initial work-hardening on the positive slip direction are roughly the same as that on the negative one, that is, the directionality of latent system is hardly existing. The relative orientation of latent system has remarkably influenced on the initial work-hardening, but does not on the latent hardening. It is seen that there is the stronger dislocation interaction between latent system and primary one, the higher initial work-hardening. The prestrain of primary system has also an effect on the initial work-hardening, but none on the latent hardening. It is seen that the initial work-hardening tends to become reducing with increasing prestrain. Based on the experimental results, a hardening rule for crystal plastic deformation could be proposed approximately, that is, except the hardening on the system negative to the active system is very low, the latent hardening on other systems is about the same as the self-hardening.