Tungsten-molybdenum alloys

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As a tungsten-molybdenum alloys are called high density tungsten alloys having the alloy components nickel , copper , iron , molybdenum in varying compositions.

overview

They have excellent strength and mechanical stability at high temperatures (up to 1900 ° C). Their high ductility and toughness have a greater tolerance for imperfections and brittle fracture than ceramics and they combine a very high density (up to 18.5 g / cm³) with machinability that is otherwise not available with tungsten .

use

The alloys are mainly used in technical areas in which materials have to withstand high temperatures:

  • High temperature heating elements, radiation shields, extrusions, dies etc .;
  • Rotating X-ray anodes are used in clinical diagnostics;
  • Electrodes and components in glass melting furnaces
  • Heat sink with thermal expansion suitable for silicon semiconductor chips;
  • Spray coatings on automobile piston rings and machine components to reduce friction and wear.
  • Spray nozzles made of TZM using plastic injection molding technology
  • Turbine blades that are exposed to very high temperatures

TZM alloy (high temperature alloy)

TZM is a solid-solution hardened and particle-reinforced molybdenum based alloy. The development of a Mo-Ti mixed crystal with finely divided Ti carbides leads to very good strength properties at temperatures of up to 1400 ° C. The recrystallization temperature of TZM is approx. 250 ° C higher than that of molybdenum and TZM offers better weldability.

TZM molybdenum is an alloy of molybdenum, 0.50% titanium, 0.08% zirconium and 0.01-0.04% carbon. TZM molybdenum is manufactured using either P / M or Arc-Cast technologies and is of great use due to its high strength / high temperature applications, especially above 2000 ° C. TZM molybdenum has a higher recrystallization temperature, higher strength, hardness and good toughness at room temperature and elevated temperatures than unalloyed molybdenum. In addition, TZM has good thermal conductivity, low vapor pressure, good corrosion resistance, and is easily machinable.

TZC alloy

The TZC alloy has very good heat resistance and a high recrystallization temperature; it also has good plasticity at room temperature. The alloy can be made using powder metallurgy and the arc melting method. TZC (1.2% titanium, 0.3% zirconium, 0.1% CO 2 ),

Other alloys

Other tungsten-molybdenum alloys are:

  • MHC (1.2% hafnium, 0.05% carbon)
  • ZHM (1.2% hafnium, 0.4% zirconium, 0.12% carbon).

literature

  • Richard Kieffer, Werner Hotop: Powder metallurgy and sintered materials . 2nd Edition. Springer-Verlag, Berlin / Göttingen / Heidelberg 1948, ISBN 978-3-642-94557-1 , p. 267 ( limited preview in Google Book search).

Individual evidence

  1. ↑ TZM (titanium-zirconium-molybdenum). (PDF; 56 kB) ThyssenKrupp Materials Switzerland, accessed on April 24, 2012 .