The invention relates to a method for preparing niobium alloy sheet by powder metallurgy, which comprises the following steps: first, the niobium alloy scraps are polished, pickling, washing and drying in turn, and then hydrogen-osmotic dehydrogenation treatment, and then sieving, pickling, washing and drying in turn, to obtain coarse and fine diameter powder; Second, the coarse diameter powder, fine diameter powder and the forming agent are mixed evenly to obtain the mixed powder, and the blank is obtained after pressing and forming; Third, pre-sintering treatment, and then seal welding; Fourth, hot isostatic pressing. Vacuum heat treatment to obtain niobium alloy sheet. The method of preparing niobium alloy sheet by powder metallurgy is especially suitable for low density Nb-Ti-Al V-Zr alloy; The invention can achieve the purpose of preparing niobium alloy sheet at low cost by reasonably combining and optimizing the processes of hydrogenation dehydrogenation method, hot isostatic pressing method, hot rolling and cold rolling etc.
At present, the turbine inlet temperature of the advanced aircraft engine is greater than 1350℃, the density of the nickel-based alloy used now is 8.0g/cm3 ~ 9.2g/cm3, the melting point is 1300℃ ~ 1350℃, and the maximum working temperature is less than 1200℃, so special processing and cooling technology must be used to use; Its application in new and advanced aerospace spacecraft is limited due to its heavy ratio and limited operating temperature. By reducing material density or mass, it can increase payload, extend range, and reduce fuel consumption, which is an important idea in aerospace design. The new Nb-Ti-Al low density niobium alloy is an important candidate material to meet these objective requirements. Because of its low density, easy processing and good oxidation resistance, it has become a new class of materials that attract attention, which is suitable for important high-temperature parts in aerospace engineering. Due to the addition of different alloying elements, this series of alloys can be divided into Nb-Ti-Al elastic alloys, Nb-Ti-al-V-Zr alloys and Nb-Ti-al-Cr-HF-W-Mo alloys.
For Nb-Ti-Al-V-Zr series niobium alloy, it belongs to the category of low-density niobium alloy, the density of the alloy is about 5.8g/cm3 ~ 6.3g/cm3, much lower than Nb521 or C103 niobium alloy. In other literatures, the preparation of niobium alloy plate and bar is usually first prepared by electron beam melting or plasma arc melting, then by forging or extrusion processing to open the billet, refine the grain structure, improve the plasticity of the alloy, and finally by forging or rolling the blank is prepared into the required specifications of plate and bar. However, the niobium alloy plate prepared by the process route has a low yield, about 20% to 30%, and because of the alloy's high hardness and high room temperature strength, the turning process is difficult, and the stress relief annealing over 1000℃ can not significantly soften the material, which is not conducive to the recycling of scraps, and it is difficult to reduce the cost of alloy preparation. Therefore, it is urgent to develop a simple and economical method for preparing sheet metal.
