Welding of TZM and WRe refractory alloys
TZM alloy is a refractory alloy formed by adding alloy elements (such as Ti and Zr) to molybdenum matrix. It has high recrystallization temperature, excellent high temperature mechanical properties and good corrosion resistance. It has been widely used in aviation, aerospace, nuclear energy and other fields, such as: Using its excellent high temperature mechanical properties, can be used for spacecraft cooling panel, rocket engine nozzle, torpedo engine to withstand high temperature valve body; Using its higher melting point, can be used for seamless stainless steel perforated top, high temperature furnace wall and hot isostatic press heat insulation screen and other high temperature structural materials; TZM alloy in electronic and electrical industry applications are also more, such as electron tube cathode, grid, high voltage rectifier original semiconductor film integrated circuit; In addition, TZM alloy is also widely used in nuclear energy equipment, such as radiation shield, support frame, heat exchanger, rail, etc.
WRe alloy, tungsten as the matrix, rhenium dissolved in tungsten to form a body centered cubic solid solution enhanced tungsten-rhenium alloy, with a series of excellent properties such as: high melting point, high density, high hardness, low thermal expansion coefficient, good corrosion resistance and oxidation resistance, excellent electrical and thermal conductivity and ray absorption. It has become a key material in the fields of national defense industry such as weapons and equipment, aerospace, atomic energy, and advanced technology such as microelectronics information, electrical engineering, and mechanical processing. For example, in the field of weapons, it can be used for ultra-high speed kinetic energy piercing projectile; In the field of nuclear fusion, plasma-oriented materials can be used in fusion reactor devices.
The effective connection of TZM and WRe dissimilar refractory alloys is the key to expand the application of refractory alloys in aerospace, nuclear energy, weapons and other fields. However, the connection between the two materials is very difficult due to the large differences in their physical and chemical properties (such as large differences in melting points). At present, fusion welding, brazing, solid phase diffusion bonding and transient liquid phase bonding are mainly used to realize the connection of superalloy.
The Spark Plasma Sintering (SPS) technique is a new method of rapid consolidation forming of powders by using a strong pulsed DC current flowing through powders or powders to produce Joule heat with different volume fractions. In recent years, the method began to be used in the field of welding, can realize the same materials (alloy and alloy, ceramic and ceramic), dissimilar materials (alloy and ceramic). Compared with traditional solid-phase diffusion welding, SPS solid-phase diffusion welding has advantages not only of fast heating rate and low energy consumption, but more importantly, SPS introduces electric field on the basis of the temperature field and stress field required by traditional solid-phase diffusion welding. Under the action of electric field, electromigration effect can accelerate material diffusion. Therefore, SPS technology is expected to achieve effective connection of TZM and WRe dissimilar refractory alloys at lower temperature and in a short time. On the other hand, the mechanical properties of TZM and WRe alloys will decrease greatly after recrystallization at high temperature. Adding low melting point metal or alloy as the intermediate transition layer can reduce the welding temperature and avoid recrystallization in the welding process of TZM and WRe alloys. Vanadium, with melting point of 1890℃, belongs to refractory metal system with molybdenum and tungsten, and vanadium can form complete solid solution with molybdenum and tungsten. Therefore, the adoption of vanadium as the intermediate transition layer for diffusion welding of TZM alloy and WRe alloy is expected to reduce the welding temperature, avoid recrystallization of the base metal (the recrystallization temperatures of TZM alloy and WRe alloy are 1400℃ and 1750℃ respectively), obtain high quality weld microstructure, and further improve the mechanical properties of welded joints.
Our company can produce TZM plate, TZM rod, TZM wire, TZM foil, TZM machined parts, of WRe alloys, WRe bars, WRe alloys, WRe wire and WRe alloys parts according to customer demand.
