In situ observation of texture evolution during α→β and α→β phase transformations in titanium alloys investigated by neutron diffraction

Texture changes during recrystallization and the alpha-beta-alpha phase transformation in two titanium alloys were investigated in situ by timeof-flight neutron diffraction by heating in a vacuum furnace to 950 C. In commercially pure titanium, a strong texture memory effect is observed. This effect is a direct consequence of an orientation-selective a, (3 transformation, favoring new orientations produced during nucleation and grain growth. The beta-alpha transformation favors beta orientations with minimal misorientations, resulting in a strong final alpha texture that emphasizes the grain growth component. In Ti-6Al-4V, the texture memory effect is less pronounced. The high-temperature beta texture is obtained by growth of pre-existing beta nuclei. In a similar way, during cooling, the growth of alpha domains is controlled by high-temperature a orientations inherited from the beta grains with Burgers orientation relation. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.