Molybdenum metal is usually produced by powder metallurgy techniques in which Mo powder is hydrostratically compacted and sintered at about 2100°C. Hot working is done in the 870-1260°C range. Moly forms a volatile oxide when heated in air above about 600°C and therefore high temperature applications are limited to non-oxidizing or vacuum environments.
Molybdenum Alloys have excellent strength and mechanical stability at high temperatures (up to 1900°C). Their high ductility and toughness provide a greater tolerance for imperfections and brittle fracture than ceramics.
The unique properties of molybdenum alloys are utilised in many applications:
High temperature heating elements, radiation shields, extrusions, forging dies, etc;
Rotating X-ray anodes used in clinical diagnostics;
Glass melting furnace electrodes and components that are resistant to molten glass;
Sprayed coatings on automotive piston rings and machine components to reduce friction and improve wear.
For specialised applications, Mo is alloyed with many other metals like Lanthanated Molybdenum Alloy:
Mo-tungsten alloys are noted for exceptional resistance to molten zinc;
Mo is clad with copper to provide low expansion and high conductivity electronic circuit boards;
Mo-25% rhenium alloys are used for rocket engine components and liquid metal heat exchangers which must be ductile at room temperature.
Except for Molybdenum, Tungsten is also a popular metal. Tungsten is an invaluable element in the alloying process, where elements are blended to form new and improved metals known as alloys. Tungsten provides a unique contribution, as it imbues exceptional strength, corrosion resistance, and other useful properties to base metals. Besides being a great alloying element, tungsten can also be the base for its own alloys.
Tungsten alloy
Tungsten alloys, sometimes referred to as heavy alloys, are usually 90-97% tungsten with the rest of its composition being a matrix of metals which improve the ductility and machinability of the resulting alloy. There is no true naming standard for these alloys, as they are set individually by the manufacturer and are not superimposable onto a general scheme such as with the alloys of steel or aluminum.