Molybdenum

Molybdenum has unique properties that support processes and applications in the electronics, aerospace, nuclear and metal working industries. These properties include a high melting point, excellent high temperature strength, good thermal and electrical conductivity, low coefficient of expansion and low vapour pressure at elevated temperature.

Applications – Missile Industry

  • Nose cones
  • High temperature structural parts
  • Nozzles
  • Leading edges of control surfaces
  • Support vanes
  • Re-entry cones
  • Heat radiation shields

Applications – Electronics Industry

  • Cathodes
  • Magnetron end hats
  • X-ray tube components

Applications – High Temperature

  • Furnace windings
  • Structural furnace members
  • Containers for components exposed to high temperatures


TZM Molybdenum

TZM Molybdenum is an alloy of 0.50% Titanium, 0.08% Zirconium and 0.02% Carbon with the balance Molybdenum. It is manufactured using p/m or arc-cast technologies and is suited to high strength, high temperature applications, especially above 1,000°C. Compared to unalloyed molybdenum, TZM has a higher recrystallisation temperature, higher strength and hardness, as well as good ductility at room and elevated temperatures. TZM is also machinable and displays good thermal conductivity, corrosion resistance, and low vapour pressure.

Applications

  • Structural furnace components
  • Die inserts for casting aluminium
  • Hot stamping tooling
  • Rocket nozzles
  • Glass to metal seals
  • Electrodes


Tantalum

Tantalum is known for its resistance to corrosion by acids – below 150 ̊C, it is almost completely immune to corrosion by aqua regia. Its resistance to attack by body fluids means tantalum is well suited to medical applications. It is also used extensively in electrical components, while its absorption properties make it an excellent getter of residual gasses in evacuation tubes.

Applications

  • Capacitors
  • Surgical implants and instruments
  • Ink jet nozzles


Niobium (or Columbium)

Niobium, or Columbium, is a shiny grey metal that takes on a blue colour when exposed to air at room temperature. Its low capture cross section for thermal neutrons supports applications in the nuclear industry, and because it can be electrically heated and anodized to a wide variety of colours, Niobium is a popular choice for jewellery-making. Niobium is also added to iron or nickel to produce alloys in the aerospace, medical and electronics industries.

Applications

  • Jet engines
  • Rocket nozzles
  • Semi-conductor equipment
  • Reaction vessels
  • jewellery


Tungsten

Tungsten has the highest melting point and the lowest vapour pressure of all metals, which makes it an excellent material for high-vacuum technology and related applications at the highest temperatures. Its low thermal expansion, high melting point and impressive dimensional stability at high temperatures mean that Tungsten is used extensively for glass seals. Tungsten is often used in high temperature furnace construction because of its electrical resistance characteristics, while its density gives the metal high capacity to absorb radioactive radiation.

Applications

  • High temperature furnaces
  • Arc lamps
  • Welding electrodes
  • Glass-to-metal seals
  • Vacuum deposition
  • Medical apparatus
  • Lamp components
  • Lamp filaments

Applications – In alloy form (heavy metal or alloy)

  • Munitions
  • Radioactive shielding
  • Counter balances


Rhenium

Rhenium has one of the highest densities and melting points of any element. It does not have a ductile to brittle transition temperature and does not form carbides. High resistivity combined with low vapour pressure make it ideal for filament applications, while its resistance to corrosion means it can resist acid attack and the mechanical effects of electrical erosion. Rhenium is beneficial as an alloying addition to other refractory metals as it greatly enhances the ductility and tensile strength of these alloys.

Applications

  • Mass spectrometer filaments
  • Grid heaters
  • Cathode cups
  • Thermocouples
  • Nuclear reactors
  • Semiconductors


Refractory Metals and Alloys

Physical Properties UNIT Molybdenum TZM Molybdenum Tantalum Niobium Tungsten Rhenium
Density lb/cu in 0.369 0.37 0.6 0.31 0.7 0.77
Density gm/cm3 10.30 10.22 16.6 8.57 19.30 21.20
Melting Point °F 4760 4753 5425 4380 6170 5767
Melting Point °C 2625 2623 2996 2415 3410 3180
Electrical Resistivity micro-ohm-cm 5.17 6.85 12.40 13.10 5.5 13.5
Thermal Conductivity cal/cm2/cm°C/sec 0.35 0.30 0.13 - 0.48 0.39
Specific Heat Cal/gm/°C 0.061 0.073 0.036 0.065 0.032 0.033
Recrystalization Temp. °C 1100 1400 - 800 - -
Coefficient of in/in/°F x 106 4.9 4.9 6.5 7.1 4.3 6.32
Linear Thermal Expansion m/m/°K/ x 106 4.8 4.8 6.3 7.3 4.6 6.80

Mechanical Properties UNIT Molybdenum TZM Molybdenum Tantalum Niobium Tungsten Rhenium
Tensile Strength KSI (Mpa)-RT 150 (1035) 110 (750) 50 (345) 40 (275) 250 (1725) 200 (1380)
Tensile Strength KSI (Mpa)-500°C 75 (515) - 35 (240) 30 (205) 150 (1035) 135 (930)
Tensile Strength KSI (Mpa)-1000°C 25 (175) - 15 (100) 10 (70) 75 (515) 70 (480)
Elongation %(in.) 1.0" 12 15 20 30 - 2
Typical Hardness DPH (vickers) RC 230 220 200 130 300 -
Modulus of Elasticity ksi 45,000 48,000 27,000 15,250 58,000 67,150
Modulus of Elasticity Gpa 310 320 185 105 400 483

Chemistry UNIT Molybdenum TZM Molybdenum Tantalum Niobium Tungsten Rhenium
minimum % - 99.95 Mo 99.20 Mo 98.99 Ta 99.6 Nb 99.95 W 99.97 Re
minimum % - - 0.08 - 0.12 Zn - - - -
minimum % - - 0.40 - 0.50 Ti - - - -

Specifications Molybdenum TZM Molybdenum Tantalum Niobium Tungsten Rhenium
ASTM B386 type 361 B386 type 364 B365 B392 - -
ASTM B387 type 361 B387 type 364 - B393 - -
AMS 7800 7817 7849 7850 7898/7899 -

Tungsten Heavy Alloys (WHA) – ASTM B 777 Class 1-4

These alloys contain elements such as nickel, copper and iron. With engineering properties similar to steel, they are easy to machine and can be plated or painted to enhance their corrosion protection. The materials are around 50% denser than lead that enables you to have a higher concentration of mass in a limited area.
Also known as: Mallory 1000, Densalloy, Fansteel 77, Densimet

Applications

  • Radiation shielding
  • Boring bars
  • Counterweights in aircraft and racing cars

ASTM-B-777 Class 1 Class 1 Class 2 Super Chatter Free™ Class 3 Class 3 Class 4
Chemistry 90% W  6% Ni 4% Cu 90% W 7% Ni 3% Fe 92.5% W 5.25% Ni 2.25% Fe 93% W Balance Ni Fe Mo 95% W 3.5% Ni 1.5% Fe 95% W 3.5% Ni 1.5% Fe 97% W 2.1% Ni .9% Fe
Density Gms/cc 17 17 17.5 17.7 18 18 18.5
Density Lbs/cu. in. 0.614 0.614 0.632 0.639 0.65 0.65 0.668
Hardness Rockwell C 24 25 26 30 27 27 28
Ultimate Tensile Strength (PSI) 110,000 125,000 114,000 130,000 115,000 125,000 128,000
Yield Strength .2% offset (PSI) 90,000 88,000 90,000 90,000 85,000 90,000 85,000
Elongation (% in 1") 8 14 12 10 7 12 10
Proportional Elastic Limit (PSI) 45,000 52,000 46,000 60,000 45,000 44,000 45,000
Modules of  Elasticity (PSI) 40 x 106 45 x 106 47 x 106 53 x 106 45 x 106 50 x 106 53 x 106
Coefficient of Thermal Expansion X 10-6/°C (20-400°C) 5.4 4.8 4.6 4.5 4.4 4.6 4.5
Thermal Conductivity (CGS Units) 0.23 0.18 0.2 0.27 0.33 0.26 0.3
Electrical Conductivity  (% IACS) 14 10 13 14 16 13 17
Magnetic Properties HD 17 = NIL  HD 17BB = Slightly Magnetic Slightly  Magnetic Slightly  Magnetic Slightly  Magnetic NIL Slightly  Magnetic Slightly  Magnetic

Tungsten Copper – ASTM B 702

This powder metallurgical material is produced using an infiltration process to introduce copper content that constitutes 10-40% of the product. With a typical mix of 75% Tungsten and 25% copper, materials are back-cast with copper and can be joined by welding or brazing with various supporting materials. The product displays properties such as high arc resistance, good electrical conductivity, high thermal conductivity and low thermal expansion.

Applications

  • Arcing contacts in high voltage breakers for transmission and distribution of electrical power
  • Carrier plates or heat sinks as passive cooling elements of electronic devices
  • Erosion electrodes for EDM made of Sparkal
  • Electrodes for surge protection
  • Welding and laser applications