A comparative study of the mechanical properties of high-strength β-titanium alloys

• Published in: Journal of alloys and compounds Vol. 457; no. 1; pp. 296 - 309
• Main Authors: Ivasishin, O.M., Markovsky, P.E., Matviychuk, Yu.V., Semiatin, S.L., Ward, C.H., Fox, S.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 12-06-2008; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Mechanical properties; Metals; Other heat and thermomechanical treatments; Physics; Precipitation; Treatment of materials and its effects on microstructure and properties; Mechanical properties; Precipitation; Metals; Ductility; Defects; Solution heat treatment; Rapid thermal annealing; Titanium alloys; Transmission electron microscopy; Recrystallization; Fine grain structure; Aging; Thermomechanical treatments; Cold deformation; Microstructure; Tensile properties; Recovery (properties)
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2007.03.070

The mechanical properties of four commercial β-titanium alloys (TIMETAL-LCB, Ti-15-3, β-21S, and VT22) were compared in the solution-treated-and-aged (STA) condition following thermomechanical processing comprising β solid solutioning, cold deformation (CD), continuous rapid heating, and final aging. The peak temperature during the rapid heating step was chosen to obtain either a recovered or recrystallized condition and thereby to control the distribution of residual deformation defects, which in turn influenced the size and distribution of α precipitates in the final microstructure. It was established that a good balance of high strength (in excess of 1600
MPa) and reasonable ductility could be obtained if a fine-grain microstructure with a β grain size of ∼10
μm was formed by recrystallization. The development of such a fine-grain size enabled a reduction in the aging temperature and thus increased the strength while maintaining ductility within the desired limits. In this respect, the properties could be varied to a great extent by varying the rate of heating to the aging temperature. On the other hand, aging of the recovered condition also led to a strength level of approximately 1600
MPa but with generally lower ductility than in the fine-grain, recrystallized condition. Another distinctive feature of the recovered condition was that the properties were relatively insensitive to the rate of heating to the aging temperature.