Written by AZoMOct 15 2002
Chemical Formula
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Ti6Al2Sn4Zr6Mo
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Background
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Ti6Al2Sn4Zr6Mo is a heat treatable alpha-beta alloy designed to combine the elevated temperature characteristics of Ti6Al2Sn4Zr2Mo with high strength levels. The alloy is thus competitive over Ti6Al2Sn4Zr2Mo up to approximately 454°C (850°F). It is used extensively in gas turbine applications such as discs and impellers. The alloy is also used for deep sour well piping and tooling and is listed in the MR0175 series of alloys suitable for this application.
Composition
Table 1. The composition of Ti6Al2Sn4Zr6Mo.
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C
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<0.10%
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Fe
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<0.25%
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N2
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<0.5%
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O2
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<0.15%
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Al
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5.5-6.5%
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Sn
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1.8-2.2%
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Zr
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3.6-4.4%
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Mo
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1.8-2.2%
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Si
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0.06-0.1%
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H2(bar)
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<0.125%
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H2(forging)
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<0.150%
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Ti
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Balance
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Designations
Other designations for Ti6Al2Sn4Zr6Mo include:
• AMS 4981
• MIL –T-9047
• UNS 56260
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Key Properties
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Physical Properties
Table 2. Typical physical properties for Ti6Al2Sn4Zr6Mo.
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Density g/cm3 (lb/ cu in)
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4.65 (0.167)
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Melting Range °C±15°C (°F)
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1635 (2975)
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Thermal Conductivity W/m.K (BTU/ft.h.°F)
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6.9 (4.1)
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Mean Co-Efficient of Thermal Expansion 20-100°C /°C (68-212°F /°F)
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9.4x10-6 (5.2)
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Mean Co-Efficient of Thermal Expansion 20-400°C /°C (68-752°F /°F)
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10.3x10-6 (5.7)
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Mean Co-Efficient of Thermal Expansion 20-600°C /°C (68-1112°F /°F)
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10.4x10-6 (5.8)
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Beta Transus °C±15°C (°F)
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937 (1720)
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Mechanical Properties
Table 3. Typical mechanical properties for Ti6Al2Sn4Zr6Mo.
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Tensile Strength MPa (ksi)
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1104 (160)
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1310 (190)
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0.2% Proof Stress MPa (ksi)
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1035 (150)
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1200 (174)
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Elongation Over 2 Inches %
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6
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11
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Reduction in Area %
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12
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Elastic Modulus GPa (Msi)
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114 (17)
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Hardness Rockwell C
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42
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Specified Bend Radius <0.070 in x Thickness (Annealed 857°C (1575°F), 5 min, FAC)
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4.0
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Table 4. Guaranteed minimum properties at 427°C (800°F).
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Tensile Strength MPa (ksi)
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931 (135)
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0.2% Proof Stress MPa (ksi)
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724 (105)
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Elongation Over 2 Inches %
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10
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Reduction in Area %
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30
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Fabrication
• Weldability – Limited
• Forging – Rough 871-899°C (1600-1650°F), finish 843-899°C (1550-1650°F)
• Annealing – Duplex – 816-913°C, 1-2hr, AC or faster + 593°C 4-8hrs, AC.
• Solution Treating – 843-913°C (1550-1675°F), AC, OQ or WQ.
• Ageing – 579-607°C (1075-1125°F), 8hr, AC.
• Stress Relief Annealing – 482-649°C (900-1200°F), 1-4 hrs.
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Applications
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As mentioned previously, this alloy is most commonly used for gas turbine components such as impellers and discs as well as piping and tooling.
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Source: Titanium Information Group.
For more information on this source please visit Titanium Information Group.
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