Texture heterogeneities induced by subtransus processing of near α titanium alloys

Abstract Clusters of α grains with sharp local texture, called macrozones, have been observed in titanium products and reported to reduce the fatigue performances. This work investigated how these macrozones form during manufacturing so that their development can be avoided. It mainly focused on the role of the α/β deformation step. This step converts the lamellar microstructure into equiaxed primary α p grains and secondary α s lamellar colonies inherited from the β to α transformation. A lamellar TIMETAL 834 alloy was compressed and annealed in the α/β domain. Orientation maps were acquired and combined with the corresponding microstructure to characterize the α p /α s microtexture. Moreover, advanced orientation data processing was applied to evaluate the final α p /β microtexture at the deformation temperature. The results showed that α/β processing produced macrozones of α p grains and α s colonies. The mechanisms by which they formed are investigated.