Tungsten tantalum alloy material because of its high density, high melting point, corrosion resistance, weldability and many other advantages and make it become the fusion of plasma facing materials, plasma facing materials is a very important material, it is related to the stability of the plasma in the reactor, the first wall structural materials and components from plasma bombardment damage, etc.
In the manufacturing process of tungsten-tantalum alloy, since the atomic radius of tantalum is 53% larger than that of tungsten, the atomic gap of the alloy is large when the solution is replaced, so it is difficult to reach a very high density. After using ordinary powder mixing and vacuum sintering, the porosity of the slab is still very high, and the density of the slab is difficult to reach 98%. Therefore, it is not suitable to use the traditional powder mixing and sintering method to make the tungsten tantalum alloy for nuclear reactors, and only foreign companies can mass-produce high-quality materials for the time being.
Tungsten powder with average particle size of 3.0μm ~ 8.0μm and tantalum powder with average particle size of 5.0μm ~ 8.0μm were placed in a planetary ball mill at a mass ratio of 9.5∶0.5. Absolute ethanol was used as the grinding medium. Tungsten-tantalum mixed powders were obtained by high-energy ball milling for 3h ~ 5h at the speed of 150r/min ~ 225r/min. The tungsten tantalum mixed powder in step 1 was pressed into shape by a cold isostatic press to obtain the blank of tungsten tantalum alloy plate. The pressure of the pressing molding is 150MPa ~ 300MPa, the holding time is 1min ~ 5min. The raw tungsten-tantalum alloy plate is placed in the vacuum hot pressing sintering furnace, and the pressure is 30MPa ~ 45MPa and the heating rate is 10℃/min ~ 30℃/min to heat up the vacuum hot pressing sintering furnace. After the temperature in the furnace rises to 2000℃ ~ 2200℃, it is held for 3h ~ 6h, and the tungsten-tantalum alloy plate is obtained with the cooling of the furnace. The surface of tungsten-tantalum alloy slab was polished and cut to the desired size to obtain the functional material for nuclear use.
