Tungsten block
The spall neutron source uses tungsten as the target material, because the high energy proton beam bombarding tungsten will produce a lot of heat, in order to cool it, it must be cooled by high speed water. However, tungsten block is easy to corrod and crack under high irradiation and high speed water flow, which affects the life of tungsten target. Therefore, it is necessary to weld a tantalum layer on the surface of the tungsten block to enhance the corrosion resistance of the target block and improve the life of the target.
At present, the international common method of welding tantalum layer with tungsten block is to weld tantalum sheet into a hollow box through electron beam welding technology in advance, and the hollow tantalum box size is consistent with the size of tungsten block; The tungsten block is put into the tantalum box, and then another tantalum sheet is covered. The tantalum sheet on the cover is welded with the tantalum box by electron beam welding, so that the hollow tantalum box containing the tungsten block is closed. Then, the tantalum box is packed with tungsten block and sealed with multiple layers of aspirating material. After the package is completed, the tantalum box and tungsten block are diffused together on six sides by hot isostatic pressure diffusion welding for 2-3 hours at 1500 degrees to form tantalum tungsten composite material specially used for spallation neutron source.
The invention relates to a method for welding tantalum layer with a six-sided diffusion tungsten block, which comprises at least one metal in titanium, iron or molybdenum to make an outsourcing sleeve. The outsourcing sleeve has a hollow inner cavity to accommodate a tungsten block, and the spacer and tantalum sheet are placed sequently on the inner wall of the hollow inner cavity of the outsourcing sleeve, and then the tungsten block is placed. The tantalum sheet is closely attached to the surface of the tungsten block, and the spacer separates the tantalum sheet and the outsourcing sleeve. Then, under vacuum condition, electron beam welding is performed on one or two end faces of the outer sheath. Before electron beam welding, tantalum sheet and spacer are placed on the surface of the tungsten block located on the end face of the outer sheath in sequence, and tantalum sheet is closely bonded to the surface of the tungsten block, and then the metal sheet covered with a metal sheet is welded with the electron beam of the outer sheath. Then it is put into the hot isostatic pressure diffusion welding device for diffusion welding. After the welding is completed, remove the outer sheath, that is, obtain a tungsten block with tantalum layer.
