Effect of β (110) texture intensity on α-variant selection and microstructure morphology during β → α phase transformation in near α titanium alloy

In the present work, we investigated the texture evolution as well as the role of the 3 texture intensity on the alpha-variant selection and microstructure morphology during the alpha ->beta ->alpha phase transformation in Ti60 alloy. Different microstructures and textures were obtained through forging the Ti60 bars into diameters of 45 mm denoted as D45 and 30 mm as D30. Subsequently, small samples with the same size cut from both bars were heat-treated above the beta transus followed by furnace cooling and air cooling. We found that the beta texture intensity, cooling rate, and variant selection affect both the texture intensity and microstructure morphology of the transformed alpha phase. The high temperature beta phase exhibits stronger (110) parallel to axial direction fiber texture in the beta annealed D30 bar than that for the D45 bar. A basketweave microstructure was found in the beta annealed D45 bar after air cooling whereas a coarse a colonies populated by fine alpha lamellae formed in the D30 bar. For furnace cooled samples, the a texture is stronger than that in the air cooled sample in D45 bar whereas the intensities of the textures are very similar to air cooled sample in the D30 bar. The influence of the (beta texture intensity and variant selection on the alpha texture evolution were studied by comparing the four experimental results and simulation data. The effect of alpha variant number in a beta grain on alpha texture intensity, base on variant selection, and the effects of beta texture intensity on microstructure morphology are discussed. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.