By adding Hf element to the tantalum tungsten alloy matrix to form a stable oxide, the oxide is almost not attacked by alkaline metals, thus significantly improving the corrosion resistance of the alloy, especially the high temperature corrosion resistance, the corrosion resistance of the alloy to liquid metal K, Na, Li increased to 1260℃; At the same time, due to the good affinity between Hf and oxygen, the addition of Hf element not only plays a role in solid solution strengthening in the alloy, but also promotes the combination of Hf and oxygen to form an oxide, reducing the adverse effect of oxygen on the alloy properties, making the high temperature performance and processing performance of the alloy significantly improved, in the temperature range of -160℃ ~ 1370℃, The alloys have maintained excellent ductility and strength, and are suitable for working in extreme environments such as ultra-high temperature, ultra-high pressure, high-speed airflow erosion, acute cooling and acute heating. In addition, the creep strength of the alloy is effectively improved by adding Re element to refine the grain and C element to form a second phase Ta2C pinning in the alloy to prevent the dislocation movement.
First, the raw material powder is mixed and pressed into bars, and then the sintered blank is obtained by vacuum high-temperature sintering, and then the bar of Ta-W-Hf-Re-C alloy is obtained by vacuum electron beam melting and die forging three times. The invention adopts the vacuum high-temperature sintering process, effectively removes the impurities of carbon, oxygen, nitrogen and hydrogen gas and the low melting point and volatile elements in the blank strip, at the same time completes the pre-alloying, combines with three times vacuum electron beam melting, promotes the homogenization of the alloy, effectively avoids the large amount of volatilization of Hf elements, and avoids the introduction of impurity elements. The composition content of Ta-W-Hf-Re-C alloy is effectively guaranteed, thus ensuring the performance of the bar of Ta-W-Hf-Re-C alloy.
It is characterized in that the particle size of the tantalum powder, tungsten powder, hafnium powder, rhenium powder and carbon powder described in step 1 does not exceed 60 mesh, and the mass purity is not less than 99.5%. By controlling the particle size of each raw material powder, the mixture is uniform, which is conducive to improving the uniformity of the alloy, and at the same time, the raw material powder with high quality and purity is adopted, avoiding a large amount of impurities from the source, and further ensuring the composition content of the alloy.
By adding Hf element to the matrix of tantalum tungsten alloy to form a stable oxide, the corrosion resistance, high temperature performance and processing performance of the alloy are improved, and the alloy maintains excellent ductility and strength within a wide temperature range from low to high temperature. At the same time, the creep strength of the alloy is effectively improved by adding Re and C. It makes the alloy suitable for working in extreme environment such as ultra-high temperature, ultra-high pressure, high-speed airflow erosion, rapid cooling and rapid heating.
