Molybdenum and molybdenum alloys are refractory metal and alloys with a very high melting point (non-alloy 2623 °C) and a low thermal expansion coefficient. They are used to fabricate evaporation crucibles, electrodes, rocket technology, furnace components, glass and zinc processing tools, and electrical contacts.
Molybdenum alloys come in a variety of alloy types. The most common types are TZM, MoW, and MoRe.
- TZM (titanium, zirconium, molybdenum) is molybdenum’s primary alloy. It has twice the strength of pure molybdenum at temperatures over 1300°C and offers better weldability, but is roughly thirty percent more expensive to buy and machine. It is used in high temperature applications that require high strength, such as rocket nozzles, furnace structural components, and forging dies.
- MoW (molybdenum-tungsten) is an alloy that provides better corrosion resistance against molten zinc, higher recrystallization temperature, and higher strength than pure molybdenum. It is used in components for zinc processing, stirrers for the glass industry, and sputter targets for coating technology.
- MoRe (molybdenum-rhenium) is an alloy that offers the strength of moly with the ductility and weldability of rhenium. It is a costly alloy and it is only available in a very limited size range. It offers significant advantages in thin foil applications for high temperature delicate parts, especially those that must be welded. It is used in rocket propulsion components for the aerospace industry, welded constructions such as liquid metal heat exchangers (which require ductility at room temperature), and high temperature thermoelements.
Molybdenum is also clad with copper for specialty electrical applications requiring low thermal expansion.
Specifications to Consider
Selecting metal alloys requires an analysis of the desired dimensions and specifications. Dimensions to consider include outer diameter (OD), inner diameter (ID), overall length, and overall thickness. Other specifications of importance (based on application) include product shape, tensile strength, yield strength, melting point, conductivity, corrosion resistance, ductility, and malleability. These properties differ based on the forming method and alloy composition.