Abstract
A study was initiated to understand the effect of grain refinement on mechanical properties of TiAl-based alloys at room and elevated temperatures. The following was found in that study. Utilizing a processing approach that includes homogenizing annealing or deformation in the α-phase field, followed by multi-step isothermal forging in the γ+ α2 phase range at relatively low strain rates and a continuously decreasing temperature, homogeneous submicro-crystalline structures were produced in titanium aluminides, facilitating further processing such as superplastic forming at temperatures below 1,000°C. Also described in this paper is a fully lamellar structure with a colony size as small as 15 µm, produced in gamma TiAl-based alloys containing borides by the fast-heating of an initially submicro-crystalline structure in the alpha-phase range followed by air cooling.
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References
F.H. Froes, C. Suryanarayana, and D. Eliezer, “Synthesis, Properties and Applications of Titanium Aluminides,” J. Mater. Sci., 27 (1992), pp. 5113–5140.
P. Bartolotta et al., “The Use of Cast Ti-48Al-2Cr-2Nb in Jet Engines,” JOM, 49 (5) (1997), pp. 48–50, 76.
Y.-W. Kim, and D.M. Dimiduk, “Designing Gamma TiAl Alloys: Fundamentals, Strategy and Production,” Structural Intermetallics 1997, ed. M.V. Nathal et al. (Warrendale, PA: TMS, 1997), pp. 531–543.
V.M. Imayev et al., “An Approach to Ductility Improvement of TiAl and Ti3Al Titanium Aluminides Based on Microstructure Control, Structural Intermetallics 1997, ed. M.V. Nathal et al. (Warrendale, PA: TMS, 1997), pp. 505–514.
Y.-W. Kim, “Ordered Intermetallic Alloys, Part 3: Gamma Titanium Aluminides,” JOM, 46 (7) (1994), pp. 30–40.
S.L. Semiatin et al., “Processing of Intermetallic Alloys,” Structural Intermetallics 1997, ed. M.V. Nathal et al. (Warrendale, PA: TMS, 1997), pp. 263–276.
C.T. Liu et al., “Tensile Properties and Fracture Toughness of TiAl Alloys with Controlled Microstructures,” Intermetallics, 4 (1996), pp. 429–440.
R.M. Imayev et al., “Hot Deformation of Gamma Titanium Alloys: Fundamentals and Application,” Gamma Titanium Aluminides 99, ed. Y.W. Kim, D.M. Dimiduk, and M.H. Loretto (Warrendale, PA: TMS, 1999), pp. 565–572.
G.A. Salishchev et al., “Processing and Deformation Behavior of Gamma TiAl Alloys with Fine-Grained Equiaxed Microstructures,” Advanced Performance Materials, 6 (1999), pp. 107–116.
G.A. Salishchev et al., “Formation of a Lamellar Structure with a Fine Colony Size in Gamma Titanium Aluminides by Rapid Heating,” Gamma Titanium Aluminides 99, ed. Y.-W. Kim, D.M. Dimiduk, and M.H. Loretto (Warrendale, PA: TMS, 1999), pp. 291–294.
G.A. Salishchev et al., “Formation of a Submicrocrystalline Structure in TiAl and Ti3Al Intermetallics by Hot Working,” Mater. Sci. Eng. A, A286 (2000), pp. 236–243.
V.M. Imayev et al., “Low-Temperature Superplasticity of Submicrocrystalline Ti-48Al-2Nb-2Cr Alloy Produced by Multiple Forging,” Scripta Materialia, 40 (1999), pp. 183–190.
R.M. Imayev et al., “Low-Temperature Superplasticity of Submicrocrystalline Intermetallics,” Materials Science Forum, 304–306 (1999), pp. 195–200.
G.A. Salishchev and R.M. Galeev, “Dynamic Recrystallization and Superplasticity of Metals and Alloys,” Recrystallization ’90, ed. T. Chandra (Warrendale, PA: TMS, 1990), pp. 603–608.
G.A. Salishchev et al., “Formation of a Submicrocrystalline Structure in TiAl and Ti3Al Intermetallics via Hot Working,” Investigations and Applications of Severe Plastic Deformation, ed. T.C. Lowe and R.Z. Valiev (Kluwer Acad. Publ., the Netherlands, 2000), pp. 49–55.
H.J. McQueen and J.J. Jonas, “Recovery and Recrystallization during High Temperature Deformation,” Treatise on Materials Science and Technology, 6, Plastic Deformation of Materials, ed. R.J. Arsenault (New York: Academic Press, 1975), pp. 393–493.
V.M. Imayev, R.M. Imayev, and G.A. Salishchev, “Porosity of TiAl Intermetallic Compound with Micro- and Submicrocrystalline Structure after Superplastic Deformation,” Mater. Sci. Eng., A208 (1996), pp. 226–231.
G.A. Salishchev et al., “Microstructure and Mechanical Properties of Ti-48Al-2Nb-2Cr Alloy after Thermomechanical Processing,” The Third Pacific International Conference on Advanced Materials and Processing (PRICM 3), vol. 1, ed. M.A. Imam et al. (Warrendale, PA: TMS, 1998), pp. 833–840.
R.M. Imayev et al., “Effect of Grain Size and Partial Disordering on Ductility of Ti3Al at Temperatures of 20°C to 600°C,” Acta Materialia, 47 (6) (1999), pp. 1809–1821.
V.M. Imayev et al., “Effect of Strain Rate on Twinning and Room Temperature Ductility of TiAl with Fine Equiaxed Microstructure,” Scripta Mater., 36 (8) (1997), pp. 891–897.
J. Karch, R. Birringer, and H. Gleiter, “Ceramics Ductile at Low Temperature,” Nature, 330 (1987), pp. 556–558.
P.J. Maziasz and C.T. Liu, “Development of Ultrafine Lamellar Structures in Two-Phase Gamma-TiAl Alloys,” Metall. Mater. Trans. A, 29A (1998), pp. 105–117.
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For more information, contact F.H. Froes, Institute for Materials and Advanced Processes, University of Idaho, Mines Building, Room 321, Moscow, Idaho 83844-3026; (208) 885-7989; fax (208) 885-4009; e-mail imap@uidaho.edu.
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Salishchev, G.A., Imayevare, R.I., Senkov, O.N. et al. Microstructural control in Ti-Al for enhanced mechanical properties. JOM 52, 46–48 (2000). https://doi.org/10.1007/s11837-000-0069-1
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DOI: https://doi.org/10.1007/s11837-000-0069-1