The creep anisotropy of hexagonal close-packed metals was thought to be controlled by the crystallographic texture. Here, it was shown that the creep anisotropy of cold-worked Zr–2.5Nb tubes was also very dependent upon the anisotropic dislocation structures introduced by cold work. The contribution of each slip system to the creep deformation of an individual grain orientation depended upon the activity of that slip system during prior cold-work. This conclusion was reached by comparing the self-consistent visco-plastic polycrystalline models with thermal creep tests performed on internally pressurized thin-wall capsules with different textures under a transverse stress of 300MPa at 350C, where dislocation creep was the dominant operating mechanism. The non-uniform dislocation distributions prior to creep were derived by simulating the cold-work process of Zr–2.5Nb tubes from an elastoplastic self-consistent model.

Influence of Prior Dislocation Structure on Anisotropy of Thermal Creep of Cold-Worked Zr–2.5Nb Tubes. W.Li, R.A.Holt, M.R.Daymond, F.Xu: Journal of Nuclear Materials, 2011, 412[1], 138-44