Refractory Metals and Alloys
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 (minumum purity)99.2%
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
Tantulum (minumum purity)99.99%
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 (minumum purity)99.6%
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 (minumum purity)99.95%
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 (minumum purity)99.97%
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 Non-Magnetic | Class 1 Magnetic | 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 |
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