Microstructural evolution and final properties of a cold-swaged multifunctional Ti–Nb–Ta–Zr–O alloy produced by a powder metallurgy route

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 575; pp. 206 - 216
• Main Authors: Guo, W., Quadir, M.Z., Moricca, S., Eddows, T., Ferry, M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15-07-2013; Elsevier
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Elasticity. Plasticity; Exact sciences and technology; Forging; Forming; Gum Metal; Materials science; Mechanical properties; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure and texture; Multifunctional titanium alloy; Other heat and thermomechanical treatments; Physics; Powder metallurgy. Composite materials; Production techniques; Swaging; Technology; Treatment of materials and its effects on microstructure and properties; Microstructure and texture; Mechanical properties; Forging; Gum Metal; Swaging; Multifunctional titanium alloy; Cubic lattices; Beta phase; Die forging; Fiber; Crystal defect; Texture; EBSD; Dislocation; Solution heat treatment; Elongation at fracture; BCC lattices; Thermal expansion coefficient; Stress effects; Titanium alloy; Crystal twin; Elastic modulus; Powder metallurgy; X ray diffraction; Tensile strength; Thermal properties; Transmission electron microscopy; Non linear elasticity; Yield strength; Porosity; Sintering forging; Microstructure
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2013.03.029

Body centred cubic (BCC) β-phase multifunctional titanium alloys have been developed with a very unique combination of thermal and mechanical properties. In this investigation, a very low porosity Ti–36.8–Nb–2.7Zr–2.0Ta–0.44O (wt%) alloy was produced by powder sintering, hot forging, solution treatment and cold swaging. X-ray diffraction and transmission electron microscopy (TEM) of the solution treated alloy revealed the presence of a small amount of ω-phase in a predominantly BCC β-phase matrix. Electron backscatter diffraction (EBSD) of the swaged alloy revealed a highly elongated and fragmented microstructure, and a strong 〈110〉 fibre texture. TEM also revealed the existence of stress-induced twin lamella, dislocations and ω-phase. Consistent with previous studies on these types of alloys, the swaged alloy exhibited non-linear elasticity during tensile straining, low elastic modulus (45.4GPa), high elastic limit (2.3%), high elongation to failure (8.1%), and a high yield strength (880MPa) and tensile strength (940MPa). The coefficient of thermal expansion was also low (∼5×10−6K−1 between 50 and 300°C) in this alloy.