Aug 23 2002
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.