The so-called barrier-effect which tensile and compressive twins exerted upon the propagation of dislocations and other twins in Zr was studied. This was done by pre-deforming textured Zr at liquid-N temperatures in order to induce either tensile or compressive twins selectively. The dislocations were then annealed, hile preserving the twinning structure. Finally, the material was re-loaded at room temperature, where only prism slip, pyramidal slip and tensile twins were active. An analysis of the yield stress upon re-loading, and of the subsequent hardening response, permitted it to be concluded that the twins played a dominant role in determining the hardening, while dislocations had only a second-order effect.

Exploring the Dislocation/Twin Interactions in Zirconium. G.C.Kaschner, C.N.Tomé, R.J.McCabe, A.Misra, S.C.Vogel, D.W.Brown: Materials Science and Engineering A, 2007, 463[1-2], 122-7