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Titanium Alloys - Titanium / Palladium Alloys Grade 11 and Grade 17

Topics Covered

Background

Ti-0.15Pd – Grade 11

Ti-0.05Pd – Grade 17

Titanium Ruthenium Alloys

Composition

Designations

Key Properties

Physical Properties

Mechanical Properties

Fabrication

Background

Ti-0.15Pd – Grade 11

This alloy has mechanical properties similar to commercially pure titanium grade 1, but with palladium added to enhance corrosion resistance in crevices and reducing acid chloride environments. As with grade 1, grade 11 has optimum ductility and cold formability. It has useful strength, high impact toughness and excellent weldability.

Ti-0.05Pd – Grade 17

Grade 17 is identical to grade 11, with the exception that the palladium added to improve corrosion resistance is less then with grade 11. Mechanical and physical properties, specifications and forms are all identical to grade 11.

The alloy composition differs by the reduction of Pd to 0.04-0.08%.

Titanium Ruthenium Alloys

The poor availability and high cost of palladium have led to the development of ruthenium as an alternative alloy addition to provide similar enhancement of corrosion resistance but at lower cost. The relevant ASTM Grade is 27 (CP Grade 1 + 0.1%Ru). Mechanical and physical properties are of the same order as described for grades 11 and 17.

Composition

Table 1. Composition of titanium-palladium alloys.

. Content
Grade 11 Grade 17
O2 <0.18% <0.18%
Fe <0.20% <0.20%
H2 <0.015% <0.015%
C <0.10% <0.10%
N2 5.5-6.5% 5.5-6.5%
Pd 0.12-0.25% 0.04-0.08%
Ti Balance Balance

Designations

Other designations for Ti6Al2Sn4Zr2Mo include:

        ASTM B265

        ASTM B337 (Grade 11 only)

        ASTM B338

        ASTM B348

        ASTM B363 (WPT)

        ASTM B381

        ASTM B861

        ASTM B862

        ASTM B863

        See also ASTM list of B367 casting grades of palladium containing alloys for approximate equivalent specifications to the wrought grades above.

        UNS R52250 Grade 11

        UNS R52252 Grade 17

Key Properties

Physical Properties

Table 2. Typical physical properties for Ti6Al2Sn4Zr2Mo.

Property Typical Value
Density g/cm3 (lb/cu in) 4.51 (0.162)
Melting Range °C±15 °C (°F) 1670 (3038)
Specific Heat J/kg.°C (BTU/lb/°F) 540 (0.129)
Volume Electrical Resistivity ohm.cm (ohm.in) 56 (22)
Thermal Conductivity W/m.K (BTU/ft.h.°F) 20.6 (143)
Mean Co-Efficient of Thermal Expansion 0-100 °C/°C (0-212 °F/°F) 8.6x10-6 (4.8)
Mean Co-Efficient of Thermal Expansion 0-300 °C/°C (0-572 °F/°F) 9.2x10-6 (5.1)
Beta Transus °C±15 °C (°F) 888 (1630)

Mechanical Properties

Property Minimum Typical Value
Tensile Strength MPa (ksi) 241 (35) 345 (50)
0.2% Proof Stress MPa (ksi) 172 (25) 221 (32)
Elongation Over 2 Inches % 25 37
Reduction in Area (%) 35
Elastic Modulus GPa (Msi) 103 (15)
Hardness (Bhn) 120
Specified Bend Radius <0.070 in x Thickness 1.5
Specified Bend Radius >0.070 in x Thickness 2.0
Welded Bend Radius x Thickness 2.0
Charpy, V-Notch Impact J (ft.lbs) 109 (80)

Fabrication

        Weldability – Excellent

        Forging – Rough 871°C (1600°F), finish 788-843°C (1450-1550°F)

        Annealing – 704°C (1300°F) 2hr, AC

        Stress Relief Annealing – 482-538°C (900-1o00°F) 45mins, AC

Source: Titanium Information Group.

For more information on this source please visit Titanium Information Group.

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