Grade Ti 8Mn Alloy (UNS R56080)

Topics Covered

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

Introduction

Titanium alloys are formed when titanium is combined with other alloying metals such as manganese, aluminum, zirconium, tin and molybdenum.

Grade Ti 8 Mn alloy is an alpha-beta wrought alloy. This alloy is heat treatable and combines superior strength to weight ratio with good corrosion resistance and fabricability.

The following sections will discuss in detail about grade Ti 8 Mn alloy.

Chemical Composition

The chemical composition of grade Ti 8 Mn alloy is outlined in the following table.

Element Content (%)
Titanium, Ti 92
Manganese, Mn 8
Oxygen, O ≤ 0.20
Carbon, C ≤ 0.20
Nitrogen, N ≤ 0.070
Hydrogen, H ≤ 0.015

Physical Properties

The physical properties of grade Ti 8 Mn alloy are tabulated below.

Properties Metric Imperial
Density 4.73 g/cm3 0.171 lb/in3
Melting point 1565°C 2849°F

Mechanical Properties

The following table shows mechanical properties of grade Ti 8 Mn alloy.

Properties Metric Imperial
Tensile strength 900 MPa 131000 psi
Yield strength 810 MPa 117000 psi
Poisson’s ratio 0.33 0.33
Elastic modulus 115 GPa 16700 ksi
Shear modulus 43.2 GPa 6270 ksi
Elongation at break 14% 14%
Hardness, Brinell 318 318
Hardness, Knoop 346 346
Hardness, Rockwell C 34 34
Hardness, Vickers 333 333

Thermal Properties

The thermal properties of grade Ti 8 Mn alloy are tabulated below.

Properties Metric Imperial
Thermal expansion co-efficient (@20-100°C/68-212°F) 8.60 µm/m°C 4.78 µin/in°F
Thermal conductivity 10.9 W/mK 75.6 BTU in/hr.ft².°F

Other Designations

Equivalent materials to grade Ti 8 Mn alloy are as follows:

  • AMS 4908
  • MIL T-9047

Fabrication and Heat Treatment

Machinability

Grade Ti 8 Mn alloy is hard to machine but can be successfully done using slow speeds, high coolant flow, and high feed rates. Tooling should be performed using tungsten carbide designations C1-C4 or cobalt type high speed tools.

Forming

Grade Ti 8 Mn alloy can be hot or cold formed using hydropress, stretch or drop hammer methods.

Welding

Welding of grade Ti 8 Mn alloy should be avoided.

Annealing

Full annealing of grade Ti 8 Mn alloy can be performed by holding the material at 680°C (1250°F) for 1 h, furnace cooling to 490°C (900°F), and finally air cooling.

Hot Working

Hot working enhances the overall ductility of the material.

Cold Working

Cold working features of this material is same as that of a moderately tempered austenitic stainless steel. Post-work annealing is recommended to re-attain favorable performance properties.

Applications

Grade Ti 8 Mn alloy is mainly used in aircraft and structural parts.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback
Submit