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This work presents a detailed description of the microstructural and crystallographic texture changes observed in the transition region in a weld between two Zircaloy-4 cold rolled and recrystallized plates [1]. In the heat affected zone (HAZ) we observed the development of Widmanstätten microstructures, typical of the α(hcp) to β(bcc) phase transformation. Associated with these changes a rotation of the c-poles is found in the HAZ and fusion zone. While the base material shows the typical texture of a cold rolled plate, with their c-poles pointing 35º apart from the normal direction of the plate in the normal-transversal line, in the HAZ, c-poles align along the transversal direction of the plate and then re-orient along different directions, all of these changes occurring within a length scale in the order of mm. The microstructural and texture changes along the HAZ were interpreted as arising due to the effect of differences in the cooling rate and  grain size on the progress of the different  variants during transformation. Fast cooling rates and large  grains are associated to weak variant selection during the  transformation, while slow cooling rates and fine  grains result in strong variant selection. Also in a particular region of the HAZ, where phase transformation was incomplete, a texture memory effect was evidenced.A theoretical model was proposed to describe the origin of the variant selection mechanism. This model is based on the evaluation of the energy advantage for nucleation of  embryos in an infinite  matrix associated to the interaction between the transformation strain misfit and the elastic response of the texture medium [2]. The model was able to reproduce the observed textures after the  transformation, and also the changes on this texture due to differences in the cooling rate.

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