Characterization of Microstructure, Texture, and Microtexture in Near-Alpha Titanium Mill Products

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2013-11, Vol.44 (11), p.4881-4890
• Main Authors: Pilchak, A. L., Szczepanski, C. J., Shaffer, J. A., Salem, A. A., Semiatin, S. L.
• Format: Article
• Language: English
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Deformation; Exact sciences and technology; Materials Science; Metallic Materials; Metallurgy; Metals. Metallurgy; Microstructure; Nanotechnology; Scattering; Structural Materials; Surfaces and Interfaces; Symposium: Quantification of Texture and Microstructure Gradients in Polycrystalline Materials; Thin Films; Titanium alloys
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-013-1804-x

Microstructure, texture, and microtexture in Ti-6Al-2Sn-4Zr-2Mo-0.1Si billet/bar of three different diameters (57, 152, and 209 mm) were quantified using backscattered electron imaging and electron backscatter diffraction. All three billets exhibited a microstructure comprising a large fraction (≥70 pct) of primary alpha particles, the average size of which decreased and aspect ratio increased with increasing reduction/decreasing billet diameter, or trends suggestive of low final hot working temperatures and/or slow cooling rates after deformation. Appreciable radial variations in the volume fraction and aspect ratio of alpha particles were noticeable only for the smallest-diameter billet. Alpha-phase textures were typical of axisymmetric deformation, but were relatively weak (~3× random) for all billet diameters. By contrast, bands of microtexture, which were multiple millimeters in length along the axial direction, were relatively strong for all of the materials. The intensity and radial thickness of the bands tended to decrease with decreasing billet diameter, thus indicating the important influence of imposed strain on the elimination of microtexture and the possible influence of surface preform microstructure following the beta quench on the evolution of microstructure and microtexture.