Hafnium-free high-anti-oxidation Nb-Si-based alloy and preparation method thereof

Abstract

The invention discloses hafnium-free high-anti-oxidation Nb-Si-based alloy and a preparation method thereof, and relates to Nb-Si-based alloy. The hafnium-free high-anti-oxidation Nb-Si-based alloy is prepared from the following raw materials in atomic percentage: 12 to 24 atomic percent of Ti, 12 to 18 atomic percent of Si, 2 to 12 atomic percent of Cr, 3 to 8 atomic percent of Al and the balance of Nb. The preparation method comprises the following steps: (1) weighing the raw materials, i.e., the Nb, the Si, the Ti, the Cr and the Al according to the component proportion; (2) smelting the raw materials by adopting an electric arc furnace, and casting the raw materials after smelting is completed; (3) carrying out homogenization treatment on a cast material in an argon atmosphere; then quenching by ice water, thus obtaining the Nb-Si-based high-temperature alloy containing Nbss / Nb5Si3 / Cr2Nb complex tissues, i.e., the hafnium-free high-anti-oxidation Nb-Si-based alloy.

Description

technical field [0001] The invention relates to a Nb-Si base alloy, in particular to a hafnium-free Nb-Si base alloy with high oxidation resistance and a preparation method thereof. Background technique [0002] To a certain extent, the development level of aviation industry is an important indicator to measure a country's industrial modernization and national defense industry development level. With the development of the aviation industry, higher requirements are placed on the high temperature bearing capacity of engine blade materials. At present, the most advanced third-generation nickel-based alloy has a service temperature limit of 1150°C (about 85% of the melting point of this type of alloy). Therefore, the development of blade materials with higher temperature-bearing capacity has become the forerunner to promote the development of the aviation industry. Nb-Si-based intermetallic compound ultra-high temperature alloy has high melting point, low density and good proc...

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Problems solved by technology

But this patent has the following serious defects: ①In this patent, the alloy is filled with 1.01×10 5 Pa protective atmosphere is high-purity argon, and melting at a temperature of 2000-2400 °C will lead to a sharp increase in the pressure in the furnace cavity, and there is a greater risk in the preparation technology; ②The added Hf element is a rare metal, and the price is relatively high. , and the density of Hf is large, which is not conducive to reducing the density of the alloy; ③The high temperature oxidation resistance needs to be improved

This patent has the following deficiencies: ①Sr, as the rare metal with the least content in the earth’s crust, is relatively expensive and has active chemical properties; ②The preparation technology of this patent is similar to the patent CN 101235460A, and there is a greater risk

Although the alloy material prepared by this method has certain comprehensive properties, there are certain defects: Hf, as a rare metal, will increase the preparation cost, and the density of Hf is relatively large, which is not conducive to reducing the density of the alloy; Alloy materials are obtained through processes such as ingot making, cutting rods, directional solidification, and vacuum heat treatment. The process is complicated and will increase the cost of alloy preparation; in addition, the patent does not have the high-temperature oxidation resistance of the alloy

But the patent itself also has certain deficiencies: First, the patent not only contains rare metals such as Hf, Re, Y, but also contains volatile elements such as B and elements with high density such as Ta, Mo, and W.

However, this patent has the following disadvantages: ① the patent contains Hf element, which is not conducive to reducing the density and preparation cost of the alloy; ② the alloy structure contains Nb 5 Si 3 and Nbss two phases, lack of Cr to improve the high temperature oxidation resistance of the alloy 2 Nb phase

However, there are obvious deficiencies in this patent: firstly, the preparation process of this patent is complicated and the cost is high; secondly, the density of Ta in the alloy is relatively high, which is not conducive to reducing the density of the alloy, and the B element is easy to volatilize, and its composition ratio is not easy to control

There are certain defects in this patent: firstly, from the technical point of view, the metal powder is mixed, ball milled, and plasma discharge sintered. The preparation process of this patent is complicated and the cost is high; An important indicator; the lack of Cr with good oxidation resistance in the alloy structure 2 Nb phase, and the patent lacks information on the high-temperature oxidation resistance of the alloy; in addition, there are dense W and Hf elements in the alloy composition, which is not conducive to reducing the density of the alloy

There are certain defects in this patent: first, the preparation process is similar to that of patent CN105177385A, and the process is complicated and the cost is high; the B element contained in the alloy composition is volatile, and it is difficult to control the composition ratio; in addition, the patent does not mention the density of the alloy sample, This is precisely the very important index in plasma sintered samples

Although there are many patents on Nb-Si-based superalloys, each of them has shortcomings and defects: such as containing high-density W, Mo and other elements, volatile B and other elements, rare metal Hf and rare earth elements, the process is complicated and the cost is high. higher

At present, there is no patent on Nb-Si based superalloy with excellent comprehensive performance

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