Jul 30 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Heat Treatment
Annealing
Forging
Hot Working
Cold Working
Aging
Applications
Introduction
Grade 9 Ti 3Al 2.5V alloy is an alpha-beta alloy that has improved strength over commercially pure titanium grades. This grade also has excellent corrosion resistance, formability and weldability.
The following sections will discuss in detail about grade 9 Ti 3Al 2.5V alloy.
Chemical Composition
The chemical composition of grade 9 Ti 3Al 2.5V alloy is outlined in the following table.
|
Element |
Content (%) |
|
Titanium, Ti |
92.755 - 95.5 |
|
Aluminum, Al |
2.5 - 3.5 |
|
Vanadium, V |
2-3 |
|
Iron, Fe |
≤ 0.20 |
|
Oxygen, O |
≤ 0.15 |
|
Carbon, C |
≤ 0.050 |
|
Nitrogen, N |
≤ 0.030 |
|
Hydrogen, H |
≤ 0.015 |
|
Other, each |
≤ 0.050 |
|
Other, total |
≤ 0.30 |
Physical Properties
The physical properties of grade 9 Ti 3Al 2.5V alloy are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
4.48 g/cm3 |
0.162 lb/in3 |
|
Melting point |
≤ 1700°C |
≤ 3090°F |
Mechanical Properties
The following table shows mechanical properties of grade 9 Ti 3Al 2.5V alloy.
|
Properties |
Metric |
Imperial |
|
Tensile strength |
620 MPa |
89900 psi |
|
Yield strength |
530 MPa |
76900 psi |
|
Poisson’s ratio |
0.3 |
0.3 |
|
Elastic modulus |
100 GPa |
14500 ksi |
|
Shear modulus |
44 GPa |
6380 ksi |
|
Elongation at break |
20% |
20% |
|
Hardness, Vickers |
300 |
300 |
Thermal Properties
The thermal properties of grade 9 Ti 3Al 2.5V alloy are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal expansion co-efficient (@20-95°C/68-203°F) |
9.61 µm/m°C |
5.34 µin/in°F |
|
Thermal conductivity |
8.30 W/mK |
57.6 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to grade 9 Ti 3Al 2.5V alloy are as follows:
|
AMS 4943 |
AMS 4944 |
ASTM B265 (9) |
ASTM B337 (9) |
|
ASTM B338 (9) |
ASTM B348 (9) |
ASTM B381 (9) |
DMS 2241 |
|
GE B50TF117 |
MIL T-9046 |
MIL T-9047 |
PWA 1260 |
AMS 4954
|
|
|
|
Fabrication and Heat Treatment
Machinability
Although tough, grade 9 Ti 3Al 2.5V alloy can be machined using the right quantity of coolant flow, slow speeds and high feed rates. High-speed tools should be used for tooling this alloy and the recommended tool types are tungsten carbide designations C1-C4 or cobalt based.
Forming
Grade 9 Ti 3Al 2.5V alloy can be hot or cold formed using hydropress, power brake, stretch or drop hammer techniques.
Welding
Weldabilty of grade 9 Ti 3Al 2.5V alloy is rated as good.
Heat Treatment
The material has to be solution heat treated to 871-927°C (1600-1700°F), then held for 15-20 min and water quenched.
Annealing
The material can be fully annealed at 593-760°C (1100-1400°F) for 3 h, and then air cooled. For stress relief, the material has to be heated to 316-649°C (600-1200°F) for 3 h and air cooled.
Forging
Rough forging can be performed at 900°C (1650°F) and completed at 843°C (1550°F).
Hot Working
Hot working enhances the overall ductility of the material.
Cold Working
Cold working features of this material is same as that of austenitic stainless steel. Post-work annealing is recommended to re-attain favorable performance properties.
Aging
For aging grade 9 Ti 3Al 2.5V alloy, the material should be heated to 482-510°C (900-950 °F) for 2 to 8 h and then air cooled.
Applications
Grade 9 Ti 3Al 2.5V alloy is used in the following application areas:
-
For tubing in aircraft and engine hydraulic systems
-
Golf clubs and tennis rackets
-
Performance bicycles