Hot isostatic pressure diffusion connection method for vanadium alloys and steels. The invention comprises the following steps: machining, sleeve making, cleaning, baking, assembly, packaging, leak detection, baking and venting, clamping and hot isostatic pressing. The invention can realize the uniform transition of connecting interface elements, no intermediate phase is generated, and the connecting member has high bonding strength. It is suitable for the manufacture of cladding components of fusion reactor with vanadium alloy as the main structural material, and can meet the performance requirements of materials.
According to the properties of the two materials, fusion welding will form σ brittle phase material in the weld fusion zone, and the weld performance is difficult to be guaranteed. At present, the main ways to achieve large area seamless connection between dissimilar metals are explosion welding, brazing welding, hot pressing welding and hot isostatic pressing welding. Among them, the explosive welds generally have more pores and large size unwelded defects, and for some complex structures, the implementation is difficult to meet the requirements; Brazing generally uses low melting point brazing filler metal with high radiation activity, and its weld resistance to high temperature is poor, so it is difficult to guarantee the high temperature performance and low radiation activity of components. Both vacuum hot pressing and hot isostatic pressing are suitable for solid diffusion welding of vanadium alloy/steel. The disadvantage of vacuum hot pressing method is that it has large deformation, it is difficult to meet the requirements of precision manufacturing of fusion reactor components, and only one workpiece can be processed at a time, so it is not suitable for mass production. Hot isostatic pressure diffusion connection is a reliable welding method to realize metallurgical bonding of heterogeneous metals, which does not limit the number of workpieces and has high production efficiency. Basically no welding deformation is suitable for precision manufacturing of the first wall component of fusion reactor. Some studies have used hot isostatic pressing method to realize the connection of vanadium alloy (V4Cr4Ti) and anti-hydrogen embrittlement austenitic stainless steel HR2. However, the shear strength is only 39MPa, which cannot meet the design and manufacturing requirements of cladding components of fusion reactor.
The hot isostatic pressure diffusion connection between vanadium alloy and RAFM steel has not been reported so far. The main difficulty of the diffusion connection lies in the interface residual stress caused by the difference of thermal expansion coefficient (Vanadium alloy: 8 ~ 10× 10-6k-1; Steel: 10 ~ 14×10-6K-1), excessive residual stress may lead to interface cracking, material bending deformation and other problems, affect the quality of the connection.
