Texture evolution in two-phase Zr/Nb lamellar composites during accumulative roll bonding

We study the texture evolution and deformation mechanisms in a Zr/Nb layered composite using a combination of electron backscattered diffraction, dislocation density evolution modeling, and polycrystal plasticity simulations. Zr/Nb composites with individual layer thicknesses ranging from 1 to 4 mm one-millimeter to four-micrometers were successfully fabricated at room temperature by accumulative roll bonding. Measured texture data during rolling and stress–strain curves in compression are presented. Under severe plastic deformation, we show that the textures of each polycrystalline phase correspond to textures of severely rolled single-phase rolled Zr and Nb. A visco-plastic self-consistent (VPSC)-dislocation density based model is applied to predict the deformation textures in the individual phases. The model indicates that large-strain deformation in Zr is accommodated by prismatic, pyramidal, and anomalously basal slip, and in Nb by both image and image slip. Our findings suggest that the polycrystalline layers of four micrometers per phase are still too coarse for the bimetal interfaces to have an effect on the texture evolution.