Evolution of Texture and Deformation Mechanisms During Repeated Deformation and Heat Treating Cycles of U-6Nb

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2021-06, Vol.52 (6), p.2195-2207
• Main Authors: Brown, Donald W., Clarke, Kester D., Clausen, Bjorn, Tupper, Catherine N., Vogel, Sven, Zepeda-Alarcon, Eloisa
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Crystal structure; Crystallography; Deformation mechanisms; Evolution; Gamma phase; Heat treating; Heat treatment; High temperature; Lattice strain; Materials Science; Mechanical properties; Metallic Materials; Nanotechnology; Niobium base alloys; Original Research Article; Room temperature; Structural Materials; Surfaces and Interfaces; Texture; Thermomechanical treatment; Thin Films; True strain; Uranium
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-021-06210-y

The evolution of the crystallographic texture and lattice strain of uranium 6-weight percent niobium alloy samples are tracked during multiple deformation and heat treating cycles in an effort to understand and control the mechanical properties of the material following thermo-mechanical processing. The heavily twinned microstructure and low-symmetry crystal structure of U-6Nb result in multiple sequential active deformation mechanisms associated with distinctive deformation textures in strain ranges from 0-0.15 true strain. It is found that heating into the high-temperature γ-phase erases much of the texture formed during deformation at room temperature in the α′′-phase and resets the active deformation mechanisms. Through a small number of deformation/heat treat cycles to moderate strains, i.e. , ~ 0.13 per cycle, the flow strength of the material is recovered to its original value. However, on the fourth such cycle, a reduction of strength is observed and the sample failed.