Molybdenum and rhenium are rare metals, molybdenum rhenium alloy has high melting point and boiling point, low vapor pressure, high density, high temperature hardness and high temperature strength and many excellent high temperature properties, in metal processing, electronic industry, aerospace and nuclear industry, military and other fields have a very wide range of applications. Molybdenum-rhenium alloy is the main material of the fuel rod used in the widely used pressurized water reactor. Because molybdenum-rhenium alloy has obvious brittle fracture tendency at low temperature and produces great thermal stress during welding, there are often a lot of cracks and pores in welding joints. As for the fusion welding process, the welding temperature is too high, which will lead to the coarse grain of the heat affected zone and the weld, so that the mechanical properties of the joint are seriously reduced. If the electron beam welding is adopted, the welding parts cannot be too large due to the size of the vacuum chamber, so it is not of application value. Resistance welding and friction welding methods are not suitable for complex structure of workpiece or workpiece fine structure, can not be mass production. However, the low melting point of the solder used in brazing will reduce the high temperature performance of the material itself.
As a solid state bonding method, diffusion welding has incomparable advantages over other welding methods. Diffusion welding is carried out in vacuum, there is no influence of gas impurities on the joint, by diffusion connection of different components, the product does not need to carry out secondary processing, and can achieve a complex structure that cannot be achieved in mechanical processing. At present, the diffusion bonding technology of molybdenum-rhenium alloy mainly focuses on diffusion welding with interlayer, but the introduction of interlayer will make the process complicated, and the type of interlayer material will also affect the high temperature performance of materials, so it is of great significance to study the direct diffusion bonding of molybdenum-rhenium alloy.
The existing molybdenum-rhenium alloy connection mainly adopts interlayer polar welding, but the introduction of interlayer will make the process complicated, and the type of interlayer material will also affect the high temperature performance of the material, so a molybdenum- Rhenium alloy non-interlayer diffusion bonding method is provided.
