Grade 9 Ti 3Al 2.5V Alloy (UNS R56320)

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

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