Grade 8 Al 1Mo 1V Titanium Alloy (UNS R54810)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Annealing
     Forging
     Hot Working
     Cold Working
Applications

Introduction

Titanium alloys contain titanium and other chemical elements such as molybdenum, aluminum, vanadium, and iron.

Grade 8 Al 1Mo 1V titanium alloy is a near alpha alloy. This grade has high stiffness/density ratio, high modulus, low density, good elevated temperature tensile properties, medium to high strength, and excellent creep resistance to enable operating temperatures of up to 455°C (851°F).

The following sections will discuss in detail about grade 8 Al 1Mo 1V titanium alloy.

Chemical Composition

The chemical composition of grade 8 Al 1Mo 1V titanium alloy is outlined in the following table.

Element Content (%)
Aluminum, Al 7.35 - 8.35
Vanadium, V 0.75 - 1.25
Molybdenum, Mo 0.75 - 1.25
Iron, Fe 0.3 max
Oxygen, O 0.12 max
Carbon, C 0.08 max
Nitrogen, N 0.05 max
Hydrogen, H 0.0125 max
Titanium, Ti Remainder

Physical Properties

The physical properties of grade 8 Al 1Mo 1V titanium alloy are tabulated below.

Properties Metric Imperial
Density 4.37 g/cm3 0.158 lb/in3
Melting point ≤ 1540°C ≤ 2800°F

Mechanical Properties

The following table shows mechanical properties of grade 8 Al 1Mo 1V titanium alloy.

Properties Metric Imperial
Tensile strength 937 MPa 136000 psi
Yield strength 910 MPa 132000 psi
Poisson’s ratio 0.32 0.32
Elastic modulus 120 GPa 17400 ksi
Shear modulus 46 GPa 6670 ksi
Elongation at break 18% 18%
Hardness, Brinell 334 334
Hardness, Knoop 363 363
Hardness, Rockwell C 36 36
Hardness, Vickers 349 349

Thermal Properties

The thermal properties of grade 8 Al 1Mo 1V titanium alloy are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (@0.000-100°C/32-212°F) 8.50 µm/m°C 4.72 µin/in°F
Thermal conductivity 6 W/mK 41.6 BTU in/hr.ft².°F

Other Designations

Equivalent materials to grade 8 Al 1Mo 1V titanium alloy are as follows:

  • AMS 4915
  • AMS 4916
  • AMS 4933
  • AMS 4955
  • AMS 4972
  • AMS 4973
  • MIL F-83142
  • MIL T-81556
  • MIL T-9046
  • MIL T-9047

Fabrication and Heat Treatment

Machinability

Although tough, grade 8 Al 1Mo 1V titanium 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 8 Al 1Mo 1V titanium alloy can be hot or cold formed using hydropress, stretch or drop-hammer methods.

Welding

Weldabilty of grade 8 Al 1Mo 1V titanium alloy is rated as fair.

Annealing

Annealing of this material requires single-hold at 738°C (1450° F) for 8 h, followed by furnace cooling. Duplex single annealing is performed by heating to 788°C (1450 °F) for 1/4 h and air cooled. Stress relief annealing requires the material to be held at 593-649°C (1100-1200 °F) for 1 h and air cooled.

Forging

Rough forging can be performed at 1010-1038°C (1850-1980°F) and completed at 1010°C (1850°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.

Applications

Grade 8 Al 1Mo 1V titanium alloy is used in the following application areas:

  • In jet engine components such as forged fan and compressor blades.
  • Industrial components such as discs, spacers, seals, rings, etc.

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