High Temperature Metals Alloys

1
High Temperature Metals and Alloys
2

• High-temperature metals and alloys are used in
  many different applications and include tantalum,
  tungsten, graphite and other metals. Most
  high-temperature metals also have good corrosion
  resistance and, when alloyed together with other
  metals, are used to make superalloys that can
  be used in chemical processing plants, nuclear
  reactors, aerospace and similar environments.
  When working in high-temperature environments,
  you need parts you can rely on. Strength and
  longevity under high stress is a must.

3

• How can I be sure that Im picking the right
  product for the right application?
• When selecting high temperature metals and
  alloys, factor in the working temperature for the
  application in question. This is important
  because every high-temperature and refractory
  metal or alloy has its own unique working
  temperature. The products also have their own
  unique densities that differ across the various
  choices. For example, tungsten weighs twice as
  much as molybdenum. If your goal is to keep
  overall weight down, then you would choose the
  latter.
• If you need a metal that has both higher strength
  and higher temperature, then molybdenum TZM will
  be a better choice than pure molybdenum. An
  acronym for the molybdenum alloy
  titanium-zirconium-molybdenum, TZM contains
  titanium, zirconium, carbon and molybdenum,
  giving the alloy extra strengthening elements
  required by some applications.
•  
• Finally, if youre working on a budget and
  focused on affordability, consider using
  molybdenum or tungsten versus higher-cost options
  like tantalum or niobium. In other settings,
  using molybdenum TZMwhich is costlier than pure
  molybdenummay be offset by the materials
  increased strength at elevated temperatures. When
  making these choices, the ultimate goal should
  always be to balance finding the best possible
  metal or alloy for your high-temperature
  application, but without breaking the bank.

4

• Materials commonly associated with durability in
  these environments are as follows.
• Molybdenum
• Molybdenum Lanthanide (MoLa)
• Molybdenum TMZ
• Niobium
• Niobium C-103
• Tantalum
• Titanium CP (Grade 1 2)
• Tungsten
• Heavy Metal Tungsten
• Tungsten Carbide
• Tungsten Copper
• Tungsten Lanthanide

5

• What are high-temperature metal and alloys?
• High-temperature metals and alloys are used in
  many different applications and include tantalum,
  tungsten, graphite and other metals. Most
  high-temperature metals also have good corrosion
  resistance and, when alloyed together with other
  metals, are used to make superalloys that can
  be used in chemical processing plants, nuclear
  reactors, aerospace and similar environments.
• What types of metals and alloys fall into
  high-temperature metal and alloys?
• High-temperature metals and alloys include
  stainless steels, superalloys, refractory metals
  and certain ceramic materials.
• How are high-temperature metals and alloys used?
• These materials are often used in the manufacture
  and repair of aircraft jet engines, industrial
  gas turbines and nuclear reactors. Additionally,
  many furnaces, ductings, and electronic and
  lighting devices operate at such high
  temperatures.
• To perform successfully and economically at high
  temperatures, a material must have at least two
  essential characteristics
• It has to be strong because increasing
  temperature tends to reduce strength. It must
  have resistance to its environment, since
  oxidation and corrosion attack also increase with
  temperature.

6

• What makes these metals and alloys unique?
• With the highest melting point of all metals,
  tungsten possesses high tensile strength and
  hardness, both of which make it a good choice for
  a wide variety of applications that require both
  (e.g., heater coils, turbine blades and defense
  products). Tantalum and graphite each possesses
  both high-temperature and high-strength qualities
  and are used in everything from rockets to jet
  engines to car batteries.
• How do the various metals in this category differ
  from one another?
• All refractory metals are also considered
  high-temperature metals and alloys, but the
  category isnt limited to refractory metals. For
  instance, many of the nickel alloys are
  considered high-temperature. Nickel also readily
  alloys with many other metals, including
  chromium, iron, molybdenum and copper. This
  enables a wide variety of alloys that demonstrate
  outstanding resistance to corrosion and
  high-temperature scaling, exceptional
  high-temperature strength and other unique
  properties, such as shape memory and low
  coefficient of expansion.

7

• Selecting the Right Metal or Alloy
• When selecting electronic grade alloys,
  procurement professionals and engineers should
  carefully consider the specific application that
  theyre working on and the environment that the
  device or equipment will be operating in. This
  will determine your metal purity requirements,
  which is a key consideration due to the fact that
  within the Nickel Alloy 200 series there are
  various purity levels.
• For example, Nickel 290, a grade of nickel made
  by a powder-metallurgy process, offers very high
  purity levels that reach as high as 99.95. Often
  used in electronic applications such as
  components of hydrogen thyratrons and for battery
  applications, Nickel 290 has a low annealing
  temperature that makes it superior to other forms
  of nickel as a substrate for precious-metal
  cladding.
• Finding the right electronic grade alloy for your
  specific project is critical to ensuring proper
  functionality, heat-resistance and
  corrosion-resistance for that application. To
  guarantee the best match, start by carefully
  assessing your own project needs and then
  comparing them against the properties and
  specifications of each prospective metal alloy.

8

• For example, nickel iron alloys are used as soft
  magnetic materials, as glass-to-metal seals and
  as materials with defined thermal expansion
  properties. Invar is 36 nickel with the
  remainder being iron. As such, it has nearly zero
  coefficient of thermal expansion around room
  temperature. This makes nickel iron a good choice
  for applications where high dimensional stability
  is required (i.e., precision measuring
  instruments and thermostat rods).
• Due to its very low thermal expansion rate,
  nickel iron is also used at cryogenic
  temperatures. Alloys containing 72-83 nickel
  have the best soft magnetic properties and are
  used in transformers, inductors, magnetic
  amplifiers, magnetic shields and memory storage
  devices.