Preparation and process analysis of molybdenum alloy materials
Molybdenum and molybdenum alloy materials, such as molybdenum plates, molybdenum rods, molybdenum wires, molybdenum tubes, molybdenum foils, etc., are prepared using powder metallurgy and subsequent deformation processing.
The mixed molybdenum and molybdenum alloy powders are made into green bodies using conventional pressing or isostatic pressing techniques. The compact is sintered at a high temperature of 2000-2200°C in a hydrogen protective atmosphere to improve its strength and density so that it can adapt to further deformation processing. The sintered billet is extruded, forged, rolled or rotary forged within the temperature range of 1200-1500C. Material density increases with increasing deformation. Forgings, round bars and plates are all produced using this process. The thick wire is prepared by high-temperature rolling and drawing, and the thin wire is prepared by low-temperature drawing. The melting point of pure molybdenum is as high as 2620C. The high melting point and high temperature strength allow the material to be used at temperatures up to 1900°C.
Depending on the area shrinkage during processing, molybdenum can recrystallize between 80O°C and 1200°C. Spontaneous grain growth occurs between 1600°C and 1800°C, resulting in a significant reduction in strength and hardness. Due to its good high-temperature mechanical stability, molybdenum, molybdenum alloys, and aluminum machined parts have many applications. Among the more typical applications are:
1. Lighting industry: supporting tungsten molybdenum rods, molybdenum pins, molybdenum hooks, and aluminum rings in traditional incandescent lamps; tungsten twisted wire core rods; molybdenum strips used for sealing with quartz glass in low and high-pressure mercury lamps and halogen lamps ; Shields for reducing the brightness of car headlights; High temperature molybdenum wire for car and motorcycle headlight support rods.
2. Electronic tube industry: molybdenum wire used for vacuum-tight connection with borosilicate glass in electron tubes, especially the surface-polished molybdenum pins; grilles made of molybdenum wire that can withstand huge thermal stress; used to improve electronics Gold-plated molybdenum wire with emission characteristics; anode, auxiliary anode, cathode support element and other structural parts in electron tubes such as emission tubes, short-wave tetrodes, and high-power tetrodes; molybdenum end caps and molybdenum tube pins in microwave magnetrons wait.
3. Semiconductor technology: The thermal expansion coefficient of molybdenum is similar to that of silicon. Molybdenum has been widely used in transistors and semiconductor components. High-quality molybdenum discs for silicon single crystal substrates, molybdenum discs and rings for cathode side connections.
4. Switches and contacts: mercury switches and special contacts for telephone relays.
5. Isothermal forging: Titanium alloy and super alloy molybdenum or TZM isothermal forging mold with high mechanical stability in the temperature range of 900-1100°C.
6. Nuclear technology: sintering devices, sintering boats and sintering trays used in nuclear fuel manufacturing, high-temperature flow elements used for exterior wall protection and reversing modules in nuclear fission devices.
7. Lighting industry: discharge tube arc electrodes, filaments, filament wire annealed tungsten tubes, evaporation boats, welding electrodes, etc.
8. Electronics industry: semiconductor substrates, electron tube grids, anodes, passive cooling device radiators, capacitor sintering boats and cups, etc.
9. Medical systems: X-ray targets and their fasteners, fixed anodes, detector components, collimators, shielding covers, containers and accessories.
10. High-temperature furnace manufacturing: heating elements, heat shields, material racks and other components, sintering boats, fasteners, etc.
