Preparation method of tantalum and tantalum alloy parts, adding tantalum powder or tantalum alloy powder and dispersant into ball mill for dissociation and ball grinding; Add the ball mill tantalum or tantalum alloy powder into the light curing monomer, then add dispersant, defoamer, and add photoinitiator under the condition of avoiding light, stir evenly to get the mixed slurry; The mixed slurry is added into the photocuring equipment, and the tantalum and tantalum alloy parts are printed layer by layer and point by point according to the 3D model by surface exposure or point scanning method using ultraviolet light beam. Finally, the blank is put into sintering furnace for degreasing and hot isostatic pressing to obtain tantalum and tantalum alloy parts. The preparation method of the invention adopts the light curing forming technology, which can prepare parts of any complex shape, avoid the dependence on the mold, shorten the processing time, reduce the manufacturing cost, and improve the forming efficiency of tantalum and tantalum alloy parts.
Tantalum and tantalum alloys have excellent properties such as high density, corrosion resistance, excellent high temperature strength, good workability and low plastic/brittle transition temperature. Most of them are concentrated in high temperature structural materials and corrosion resistant materials, so they are widely used in aviation, aerospace and chemical industries. Tantalum and tantalum alloys are formed into parts through powder metallurgy or smelting processes combined with traditional mechanical processing methods. The traditional metal billet is usually heat treated by forging and combined with mechanical machining by hammering or stamping to form parts. However, tantalum and tantalum alloy are prone to oxidation during hot processing, and embrittlement occurs even when the temperature is higher. Traditional processing technology is mainly used to produce small and simple products, but for complex structural parts, the traditional processing method can not meet the requirements.
The method can be used for pure tantalum parts and also for preparing tantalum alloy parts. Tantalum alloy mainly includes tantalum tungsten alloy, tantalum tungsten hafnium alloy, niobium tantalum tungsten alloy and so on. Solidified forming green billet is a mixture of organic binder and parts, which is put into sintering furnace for post-processing, mainly including degreasing and hot isostatic pressing process. First, low temperature degreasing is used to remove the binder, and then hot isostatic pressing is carried out to obtain dense tantalum and tantalum alloy parts with excellent performance. Degreasing temperature was determined according to thermogravimetric (TG) curve, and the temperature range with serious mass change was selected as the degreasing temperature, ranging from 400°C to 600°C. In order to ensure the complete defatting process, the holding time is 2h ~ 4h. In order to reduce the influence of heating process on the properties of blank, the gradient heating mode was selected, and the temperature rise rate was controlled above 5°C/min before reaching the degreasing temperature.
