The effect of stored prismatic dislocations on the onset and growth of {10•2} and {11•2} twins in pure Zr was investigated. A set of temperature jump tests, some combined with a strain path changes, were performed here to exploit the fact that slip-dominated plastic behavior occurs at room temperature and twin-dominated plastic behavior at lower temperatures. In some of the tests the material was pre-strained to various levels at room temperature to introduce prismatic slip dislocations, and then reloaded at liquid nitrogen. In other tests the material was pre-strained at liquid nitrogen, to different levels and in different directions, to generate either {10•2} tensile or {11•2} compressive twins, and then reloaded at room temperature. These tests were interpreted with a recently developed dislocation-density based single crystal model in order to elucidate slip-twin interactions operating at the nanometer scale. The analysis suggested that (1) stored dislocations increase the resistance for further slip and for {11•2} twin propagation, but not for {10•2} twin propagation; (2) the onset of {11•2} twinning was insensitive to the amount of stored dislocations; (3) substantial slip occurs within the twin oriented domains, which could either increase or decrease the hardening rate by comparison to the one without twins.

On the Interaction between Slip Dislocations and Twins in HCP Zr. L.Capolungo, I.J.Beyerlein, G.C.Kaschner, C.N.Tomé: Materials Science and Engineering A, 2009, 513-514, 42-51