High-purity hafnium-nickel alloy and preparation method thereof

Abstract

The invention relates to the technical field of metal materials, and discloses a high-purity hafnium-nickel alloy and a preparation method thereof.According to the high-purity hafnium-nickel alloy, the vacuum electron beam horizontal furnace smelting technology is adopted, and the cost is reduced by controlling the purity of raw materials and smelting parameters, so that the high-purity hafnium-nickel alloy is prepared. Sponge hafnium with the purity of 96% and a nickel plate with the purity of 99.99% which meet the YS / T399-2013 standard are selected as raw materials of the alloy, an electron beam horizontal furnace with the vacuum degree better than 10 <-3 > Pa is adopted for smelting, the overheating temperature is high during smelting, the liquid state maintaining time is long, the refining and purifying process of the material is fully and effectively carried out, and meanwhile, the alloy has the advantages of being high in mechanical strength, high in mechanical strength and good in mechanical property. The main processes of degassing, decomposition, deoxidation, volatilization of metal impurities and floating of infusible impurities of the materials in the smelting process are fully carried out in the high-vacuum environment, and therefore the high-purity hafnium-nickel alloy with the purity being 99.9% or above can be directly prepared with low cost through sponge hafnium with low cost.

Description

Technical Field

[0001] The invention relates to the technical field of metal materials, in particular to a high-purity hafnium-nickel alloy and a preparation method thereof. Background Art

[0002] In recent years, nickel-based high-temperature alloys have been widely used in the manufacture of aviation jet engines and various industrial gas turbine hot end components due to their excellent high-temperature strength, high-temperature oxidation and corrosion resistance, fatigue resistance and high fracture toughness.

[0003] The nickel-based high-temperature alloys currently used generally have low plasticity and strength around 760°C (650-850°C), which leads to sudden damage of alloy parts at the end of the creep stage. Adding metal hafnium (Hf) to nickel-based high-temperature alloys is one of the effective ways to improve the medium-temperature strength and plasticity of nickel-based casting alloys. However, the melting point of hafnium is as high as 2231°C and the density is 13.31 g / cm 3 , while the melting point of nickel (Ni) is 1455 ℃ and the density is 8.9 g / cm 3 The melting points and densities of the two elements are quite different. Therefore, when using traditional induction melting equipment to prepare nickel-based high-temperature alloys, there are problems such as pure hafnium being difficult to melt and hafnium component segregation in the metal ingot after solidification. This requires the use of hafnium-nickel master alloy as an additive to add hafnium to nickel-based high-temperature alloys to reduce the melting point of hafnium-nickel alloys. It is more conducive to the alloying of hafnium to nickel-based high-temperature alloys than directly adding pure hafnium metal, and makes the distribution of hafnium in the alloy more uniform.

[0004] Traditional preparation technologies are all implemented through vacuum induction melting, and the yield is generally around 90%; the vacuum degree of the vacuum induction melting furnace used is 0.1-50 Pa, preferably below 5 Pa, which only reaches the level of medium vacuum; before melting, a new crucible needs to be made, and even a special zirconium oxide surface ceramic shell needs to be created, and the preparation cycle is long; the melting process is carried out by filling with protective gas (mainly argon), so the effect of using vacuum technology to remove impurities and gases in the melt is limited, and the purity of the actual alloy is not very ideal. In particular, when using hafnium sponge to produce hafnium-nickel alloy, hafnium oxide inclusions are easily formed inside. Hafnium dioxide has a high density (10-14 g / cm 3 ), high stability, hafnium dioxide will reduce the fluidity of liquid metal, and at the same time cause pores to form inside the alloy plate, reducing the performance of high-temperature alloy parts.

[0005] Therefore, the key is to prepare high-purity hafnium-nickel alloy with low oxygen and impurity content. Currently, there is a lack of better preparation technology at home and abroad. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a high-purity hafnium-nickel alloy and a preparation method thereof, which has the advantages of high purity, short production cycle and high yield of the hafnium-nickel alloy, and solves the problems of low purity, long production cycle and low yield of the hafnium-nickel alloy in the current technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a high-purity hafnium-nickel alloy, wherein the alloy raw materials and their mass percentages are: 88% to 92% hafnium and 8% to 12% nickel.

[0008] Preferably, the purity of the nickel is 99.99%, the particle size of the nickel particles is 10-20 mm, and the original nickel blank is a plate material, which is cut into 10-20 mm particle blocks for standby use.

[0009] Preferably, the hafnium is sponge hafnium, the purity of which meets the YS / T 399-2013 standard, and the particle size of the sponge hafnium particles is 10 to 25 mm.

[0010] Preferably, a method for preparing a high-purity hafnium-nickel alloy is prepared according to the mass percentage of the above-mentioned high-purity hafnium-nickel alloy raw material, comprising the following preparation steps: Step 1: Raw material configuration: prepare alloy raw materials according to the ratio of 88% to 92% hafnium to 8% to 12% nickel by mass, and divide all the hafnium into two equal parts by mass to complete the raw material configuration; Step 2: Loading the raw materials into the furnace: Load the raw materials from the first step into the electron beam horizontal melting furnace in three layers, close the furnace door and start vacuuming to complete the loading of raw materials into the furnace; Step 3: First vacuum electron beam melting: using a horizontal electron beam melting furnace to perform vacuum electron beam melting, including preparation before melting, melting process and parameter adjustment; Step 4: Second vacuum electron beam melting: Turn over the plate obtained in the third step, turn the head of the plate into the tail, and perform a second melting to obtain a high-purity hafnium-nickel alloy product.

[0011] Preferably, in step 2, the process of dividing the raw materials into three layers is as follows: in the first layer, one of the two equal parts of the hafnium sponge particles is evenly dispersed and laid in a cleaned copper crucible free of impurities; in the second layer, nickel particles are evenly dispersed and arranged on the hafnium sponge particles in the first layer; and in the third layer, the other of the two equal parts of the hafnium sponge particles is evenly dispersed and laid on the nickel particles in the second layer.

[0012] Preferably, the preparation and parameter adjustment before the first vacuum electron beam melting in step 3: S1.1. Preheat the electron gun of the horizontal electron beam melting furnace and evacuate the furnace. When the vacuum degree in the horizontal electron beam melting furnace is lower than 5×10 -2Pa, start cathode heating for 5 to 10 minutes; S1.2. After the cathode is heated, adjust and focus the electron beam position so that the emission current range of the electron gun is 0.5 to 3A; S1.3, adjust the scanning pattern again, widen a small dot of the electron beam emitted from the center of the crucible to 10-20cm horizontally, and slowly increase the emission current to 3.5-4A; S1.4. Finally, adjust the electron beam to the starting melting position of the crucible and 2 cm away from the top of the crucible molten pool.

[0013] Preferably, the first vacuum electron beam melting process and its parameter adjustment in step three are as follows: after the preparatory work before melting is completed, melting is started from the top position, and the melting is scanned toward the tail end at a speed of 0.6-0.7 mm / s. During the melting process, the electron beam stays in the molten pool for 3-5 seconds to melt the raw materials thoroughly, and the melting is continued until the tail end of the crucible molten pool is finished to obtain a preliminarily formed plate.

[0014] Preferably, after the first vacuum electron beam melting is completed, the initially formed plate is cooled for 1 to 3 hours and then taken out of the furnace to obtain a plate melted by the first vacuum electron beam melting.

[0015] Preferably, in the second vacuum electron beam melting process in step 4, the second melting will repeat the steps of the first melting; the beam is drawn from 10 to 20 cm away from the head of the crucible; after the beam is drawn normally, the electron beam is widened to 10 to 20 cm from the head of the crucible molten pool, and the electron beam is scanned and melted toward the tail end at a speed of 0.6 to 0.7 mm / s, and the technical parameters of other operations are the same as those of the third step, to obtain a preliminarily formed high-purity hafnium nickel alloy.

[0016] Preferably, after the second vacuum electron beam melting is completed, the initially formed high-purity hafnium-nickel alloy is cooled for 1 to 3 hours and then taken out of the furnace to obtain a high-purity hafnium-nickel alloy product.

[0017] Compared with the prior art, the present invention provides a high-purity hafnium-nickel alloy and a preparation method thereof, which has the following beneficial effects: 1. The present invention uses an electron beam horizontal furnace for smelting, which not only makes the alloy surface smooth and of better quality, but also saves the process of alloy surface finishing, thereby reducing production costs and reducing material waste. After completing electron beam smelting, it is only necessary to clean the furnace, crystallizer and gun barrel in the electron beam furnace before smelting. The cleaning time only takes 1 to 2 hours, which shortens the cleaning time.

[0018] 2. The present invention uses an electron beam melting furnace, which helps to overcome the disadvantage of metal liquid splashing during the induction furnace melting process, thereby increasing the product yield by more than 7% and the product purity to 99.9%. It solves the problem that when using a vacuum induction furnace, the molten metal liquid will adhere to the furnace wall during the melting process, leaving alloy residues that are difficult to clean, which seriously reduces the purity and yield of the metal melting.

[0019] 3. The present invention is prepared by using an electron beam melting furnace, and its preparation process has better deoxidation and impurity removal effects. The high-purity hafnium-nickel alloy finally obtained has a composition of 88% to 92% by mass of Hf and 8% to 12% by mass of Ni. The contents of other components after the first electron beam melting are: Al≤0.0045%, Co≤0.01%, Cu≤0.0022%, Fe≤0.02%, Mg≤0.005%, Ti≤0.005%, Cr≤0.002%, Si≤0.01%, Mo≤0 .01%, V≤0.01%, O≤0.05%, N≤0.007%, C≤0.02%; after the second electron beam melting, the following are achieved: Al≤0.0005%, Co≤0.01%, Cu≤0.002%, Fe≤0.01%, Mg≤0.001%, Ti≤0.001%, Cr≤0.001%, Si≤0.003%, Mo≤0.005%, V≤0.001%, O≤0.03%, N≤0.003%, C≤0.02%, and the preparation process is short and the product yield is high.

[0020] 4. The present invention adopts vacuum electron beam horizontal furnace smelting technology to reduce the cost of preparing high-purity hafnium-nickel alloy by controlling the purity of raw materials and smelting parameters. The raw materials of the alloy are selected from hafnium sponge with a purity of 96% and nickel plate with a purity of 99.99% that conforms to the YS / T399-2013 standard. The vacuum degree is better than 10 —3 Pa electron beam horizontal furnace melting, the superheat temperature during melting is high, and the liquid state is maintained for a long time, so that the refining and purification process of the material can be fully and effectively carried out. At the same time, the high vacuum environment allows the main processes of degassing, decomposition, deoxidation, volatilization of metal impurities and floating of infusible impurities in the melting process to be fully carried out, so that high-purity hafnium nickel alloy with a purity of more than 99.9% can be directly prepared at low cost using low-cost sponge hafnium. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart was prepared for the present invention. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1 , a high-purity hafnium-nickel alloy, the raw materials of the alloy and their mass percentages are: 88% to 92% hafnium and 8% to 12% nickel.

[0024] Specifically, the purity of nickel is 99.99%, the particle size of nickel particles is 10-20 mm, and the original nickel blank is a plate material, which is cut into particle blocks of 10-20 mm for standby use.

[0025] Specifically, the hafnium is sponge hafnium, the purity of which meets the standard of YS / T 399-2013, and the particle size of the sponge hafnium particles is 10 to 25 mm.

[0026] Preferably, a method for preparing a high-purity hafnium-nickel alloy is prepared according to the mass percentage of the above-mentioned high-purity hafnium-nickel alloy raw material, comprising the following preparation steps: Step 1: Raw material configuration: prepare alloy raw materials according to the ratio of 88% to 92% hafnium to 8% to 12% nickel by mass, and divide all the hafnium into two equal parts by mass to complete the raw material configuration; Step 2: Loading the raw materials into the furnace: Load the raw materials from the first step into the electron beam horizontal melting furnace in three layers, close the furnace door and start vacuuming to complete the loading of raw materials into the furnace; Step 3: First vacuum electron beam melting: using a horizontal electron beam melting furnace to perform vacuum electron beam melting, including preparation before melting, melting process and parameter adjustment; Step 4: Second vacuum electron beam melting: Turn over the plate obtained in the third step, turn the head of the plate into the tail, and perform a second melting to obtain a high-purity hafnium-nickel alloy product.

[0027] Specifically, the process of dividing the raw materials into three layers in step 2 is as follows: in the first layer, one of the two equal parts of the hafnium sponge particles is evenly dispersed and laid in a cleaned copper crucible free of impurities; in the second layer, the nickel particles are evenly dispersed and arranged on the hafnium sponge particles in the first layer; and in the third layer, the other of the two equal parts of the hafnium sponge particles is evenly dispersed and laid on the nickel particles in the second layer.

[0028] Specifically, the preparation and parameter adjustment before the first vacuum electron beam melting in step 3: S1.1. Preheat the horizontal electron beam melting furnace and evacuate it at the same time. When the vacuum degree in the horizontal electron beam melting furnace is lower than 5×10 -2 Pa, start cathode heating for 5 to 10 minutes; S1.2. After the cathode is heated, adjust and focus the electron beam so that the emission current of the electron gun is in the range of 0.5 to 3 A. S1.3, adjust the scanning pattern again, widen a small dot of the electron beam emitted from the center of the crucible to 10-20 cm horizontally, and slowly increase the emission current to 3.5-4A; S1.4. Finally, adjust the electron beam to the starting melting position of the crucible and 2 cm away from the top of the crucible molten pool.

[0029] Specifically, the first vacuum electron beam melting process and its parameter adjustment in step three: after the preparatory work before melting is completed, melting is started from the top position, and the melting is scanned toward the tail end at a speed of 0.6-0.7 mm / s. During the melting process, the electron beam stays in the molten pool for 3-5 seconds to melt the raw materials thoroughly, and the melting is continued until the tail end of the crucible molten pool to obtain a preliminarily formed plate.

[0030] Specifically, after the first vacuum electron beam melting is completed, the initially formed plate is cooled for 1 to 3 hours and then taken out of the furnace to obtain a plate melted by the first vacuum electron beam melting.

[0031] Specifically, the second vacuum electron beam melting process in step 4: the second melting will repeat the steps of the first melting; start beam drawing from 10 to 20 cm away from the head of the crucible; after the beam drawing is normal, start from the head of the crucible molten pool, widen the electron beam to 10 to 20 cm, and scan and melt toward the tail end at a speed of 0.6 to 0.7 mm / s. The technical parameters of other operations are the same as those of the third step, and a preliminarily formed high-purity hafnium nickel alloy is obtained.

[0032] Specifically, after the second vacuum electron beam melting is completed, the initially formed high-purity hafnium-nickel alloy is cooled for 1 to 3 hours and then taken out of the furnace to obtain a high-purity hafnium-nickel alloy product.

[0033] The preparation process of the present invention is used in the preparation of three embodiments, and the process is as follows: Example

[0034] The first step is raw material configuration The alloy raw materials are prepared according to the mass of Hf (hafnium) 49.5 kg and Ni (nickel) 5.5 kg. The nickel is a nickel plate with a purity of 99.99%, which is cut into 10-20 mm particle blocks. The hafnium is sponge hafnium, and its purity meets the YS / T 399-2013 standard. The particle size of the sponge hafnium particles is 10-25 mm. The hafnium is divided into two equal parts according to the mass, and the mass of each part is 24.75 kg, thus completing the raw material preparation; Step 2: Loading the raw materials into the furnace The raw materials in the first step are laid into the electron beam horizontal melting furnace in three layers, wherein the first layer is to evenly spread the prepared 24.75 kg of hafnium sponge particles in the cleaned copper crucible without impurities; the second layer is to evenly spread 5.5 kg of nickel particles on the hafnium sponge particles in the first layer; the third layer is to evenly spread the prepared 24.75 kg of hafnium sponge particles on the nickel particles in the second layer; after closing the furnace door, vacuuming is started to complete the raw material loading; Step 3: First vacuum electron beam melting When the vacuum degree in the horizontal electron beam melting furnace is lower than 5×10 -2 Pa, cathode heating was started for 5 min, the position of the electron beam was adjusted and focused, so that the emission current range of the electron gun was 0.5-3 A, the scanning pattern was adjusted, a small dot of the electron beam emitted from the center of the crucible was stretched horizontally to 20 cm, and the emission current was slowly increased to 4 A, and then the electron beam was adjusted to the starting melting position of the crucible and 2 cm away from the top of the crucible molten pool, and then the melting was started from the top position, and the melting was scanned to the tail end at a speed of 0.7 mm / s. During the melting process, the electron beam stayed in the molten pool for 3 seconds to melt the raw materials, and the melting was completed in sequence until the end of the crucible molten pool; after the first melting was completed, it was cooled for 1 hour and then taken out of the furnace to obtain the plate melted by the first vacuum electron beam; Lift the plate with a crane and place it on a clean platform. Then, select 5 to 10 particles with a diameter of about 0.5 mm from the upper, middle and lower parts of the plate by hammering. g. The chemical composition of Ni, Al, Co, Cu, Fe, Mg, Ti, Cr, Si, Mo, and V was detected by inductively coupled plasma atomic emission spectrometer. O and N were detected by oxygen and nitrogen analyzer. C and S were detected by carbon and sulfur analyzer. The element detection data showed that the mass percentages of elements in three different positions of the plate produced by the first vacuum electron beam melting were as follows: Ni: 9.84% to 10.35%, Al≤0.0031%, Co≤0.006%, Cu≤0.0021%, Fe≤0.018%, Mg≤0.0024%, Ti≤0.0045%, Cr≤0.0015%, Si≤0.009%, Mo≤0.0086%, V≤0.0089%, O≤0.0468%, N≤0.0039%, and C≤0.013%. Example

[0035] The first step is raw material configuration The alloy raw materials are prepared according to the mass of Hf 55 kg and the mass of Ni 4.7826 kg, wherein the nickel adopts nickel particles with a purity of 99.99% and a particle size of 10-20 mm; the hafnium is sponge hafnium, and its purity meets the YS / T 399-2013 standard, and the particle size of the sponge hafnium particles is 10-25 mm, and the hafnium is divided into two equal parts according to the mass, and the mass of each part is 27.5 kg, thus completing the raw material preparation; Step 2: Loading the raw materials into the furnace The raw materials in the first step are placed in three layers into the electron beam horizontal melting furnace, wherein the first layer is to evenly spread the prepared 27.5 kg of hafnium sponge particles in a clean copper crucible without impurities; the second layer is to evenly spread 4.7826 kg of nickel particles on the hafnium sponge particles in the first layer; the third layer is to evenly spread the prepared 27.5 kg of hafnium sponge particles on the nickel particles in the second layer; after closing the furnace door, vacuuming is started to complete the loading of raw materials into the furnace; Step 3: First vacuum electron beam melting When the vacuum degree in the horizontal electron beam melting furnace is lower than 5×10 -2Pa, start cathode heating for 10 min, adjust and focus the position of the electron beam, make the emission current range of the electron gun be 0.5-3 A, adjust the scanning pattern, widen a small dot of the electron beam emitted from the center of the crucible to 10 cm laterally, and slowly increase the emission current to 3.5 A, then adjust the electron beam to the starting melting position of the crucible and 2 cm away from the top of the crucible molten pool, then start melting from the top position, and scan and melt toward the tail end at a speed of 0.6 mm / s. During the melting process, the electron beam stays in the molten pool for 5 seconds to melt the raw materials thoroughly, and the melting is sequentially carried out until the end of the crucible molten pool. After the first melting is completed, it is cooled for 2 hours and then taken out of the furnace to obtain the plate melted by the first vacuum electron beam. The plate was lifted by a crane and placed on a clean platform. Then, 5 to 10 g of particles with a diameter of about 0.5 mm were selected from the upper, middle and lower parts of the plate by hammering. The chemical composition of Ni, Al, Co, Cu, Fe, Mg, Ti, Cr, Si, Mo and V was detected by inductively coupled plasma atomic emission spectrometry. O and N were detected by oxygen and nitrogen analyzer, and C and S were detected by carbon and sulfur analyzer. The element detection data showed that the mass percentage of elements contained in three different positions of the plate melted by the first vacuum electron beam was as follows: Ni: 7.76% to 8.24%, Al≤0.0015%, Co≤0.008%, Cu≤0.002%, Fe≤0.02%, Mg≤0.001%, Ti≤0.001%, Cr≤0.001%, Si≤0.002%, Mo≤0.004%, V≤0.01%, O≤0.05%, N≤0.007%, and C≤0.01%.

[0036] Step 4: Second vacuum electron beam melting The plate obtained in the third step is turned over, and the head of the previous plate is turned into the tail after turning over, and the second melting is carried out. The second melting will repeat the steps of the first melting; the beam is drawn from 20 cm away from the head of the crucible; after the beam is drawn normally, the electron beam is widened to 20 cm from the head of the crucible molten pool, and the melting is scanned toward the tail end at a speed of 0.6 mm / s. The technical parameters of other operations are the same as those of the third step; after the second melting is completed, it is cooled for 1 hour and then taken out of the furnace to obtain a high-purity hafnium-nickel alloy product.

[0037] The obtained product is in the shape of a rectangular alloy plate with dimensions of 1180 mm in length, 230 mm in width and 22 mm in thickness. The plate was lifted by a crane and placed on a clean platform. Then, 5 to 10 g of particles with a diameter of about 0.5 mm were selected from the upper, middle and lower parts of the plate by hammering. The chemical composition of Ni, Al, Co, Cu, Fe, Mg, Ti, Cr, Si, Mo and V was detected by inductively coupled plasma atomic emission spectrometer. O and N were detected by oxygen and nitrogen analyzer, and C and S were detected by carbon and sulfur analyzer. The element detection data showed that the mass percentage of elements contained in three different positions of the plate after the second vacuum electron beam melting was as follows: Ni: 7.92% to 8.12%, Al≤0.0005%, Co≤0.009%, Cu≤0.0014%, Fe≤0.0068%, Mg≤0.0009%, Ti≤0.001%, Cr≤0.001%, Si≤0.002%, Mo≤0.0041%, V≤0.0001%, O≤0.0197%, N≤0.0011%, and C≤0.0105%. Example

[0038] The first step is raw material configuration The alloy raw materials are prepared according to the mass of Hf 48.4 kg and the mass of Ni 6.6 kg, wherein the nickel is a nickel plate with a purity of 99.99%, which is cut into granular blocks of 10 to 20 mm; the hafnium is sponge hafnium, and its purity meets the YS / T 399-2013 standard. The particle size of the sponge hafnium particles is 10 to 25 mm, and the hafnium is divided into two equal parts according to the mass, and the mass of each part is 24.2 kg, thus completing the raw material preparation; Step 2: Loading the raw materials into the furnace The raw materials in the first step are laid into the electron beam horizontal melting furnace in three layers, wherein the first layer is to evenly spread the prepared 24.2 kg of hafnium sponge particles in a clean copper crucible without impurities; the second layer is to evenly spread the 6.6 kg of nickel particles on the hafnium sponge particles in the first layer; the third layer is to evenly spread the prepared 24.2 kg of hafnium sponge particles on the nickel particles in the second layer; after closing the furnace door, vacuuming is started to complete the raw material loading; Step 3: First vacuum electron beam melting When the vacuum degree in the horizontal electron beam melting furnace is lower than 5×10 -2Pa, start cathode heating for 8 min, adjust and focus the position of the electron beam, make the emission current range of the electron gun be 0.5-3 A, adjust the scanning pattern, widen a small dot of the electron beam emitted from the center of the crucible to 15 cm laterally, and slowly increase the emission current to 3.8 A, then adjust the electron beam to the starting melting position of the crucible and 2 cm away from the top of the crucible molten pool, then start melting from the top position, and scan and melt toward the tail end at a speed of 0.65 mm / s. During the melting process, the electron beam stays in the molten pool for 4 seconds to melt the raw materials thoroughly, and the melting is completed in sequence until the end of the crucible molten pool; after the first melting is completed, it is cooled for 3 hours and then taken out of the furnace to obtain the plate melted by the first vacuum electron beam; The plate was lifted by a crane and placed on a clean platform. Then, 5 to 10 g of particles with a diameter of about 0.5 mm were selected from the upper, middle and lower parts of the plate by hammering. The chemical composition of Ni, Al, Co, Cu, Fe, Mg, Ti, Cr, Si, Mo and V was detected by inductively coupled plasma atomic emission spectrometer. O and N were detected by oxygen and nitrogen analyzer, and C and S were detected by carbon and sulfur analyzer. The element detection data showed that the mass percentage of elements contained in three different positions of the plate melted by the first vacuum electron beam was as follows: Ni: 11.86% to 12.21%, Al≤0.0045%, Co≤0.01%, Cu≤0.0022%, Fe≤0.01%, Mg≤0.005%, Ti≤0.005%, Cr≤0.002%, Si≤0.008%, Mo≤0.01%, V≤0.01%, O≤0.05%, N≤0.007%, C≤0.02%; Step 4: Second vacuum electron beam melting The plate obtained in the third step is turned over, and the head of the previous plate is turned into the tail after turning over, and the second melting is carried out. The second melting will repeat the steps of the first melting; the beam is drawn from 20 cm away from the head of the crucible; after the beam is drawn normally, the electron beam is widened to 20 cm from the head of the crucible molten pool, and the melting is scanned to the tail end at a speed of 0.6 mm / s. The technical parameters of other operations are the same as those of the third step; after the second melting is completed, it is cooled for 3 hours and then taken out of the furnace to obtain a high-purity hafnium-nickel alloy product.

[0039] The product is a rectangular alloy plate with a size of 1180 mm in length, 230 mm in width and 19 mm in thickness. The plate is hoisted by an overhead crane and placed on a clean platform. Then, 5 to 10 particles with a diameter of about 0.5 mm are selected from the upper, middle and lower parts of the plate by hammering. g. The chemical composition of Ni, Al, Co, Cu, Fe, Mg, Ti, Cr, Si, Mo, and V was detected by inductively coupled plasma atomic emission spectrometer. O and N were detected by oxygen and nitrogen analyzer. C and S were detected by carbon and sulfur analyzer. The element detection data showed that the mass percentages of the elements in three different positions of the plate produced by the second vacuum electron beam melting were as follows: Ni: 11.92% to 12.16%, Al≤0.0005%, Co≤0.01%, Cu≤0.002%, Fe≤0.007%, Mg≤0.001%, Ti≤0.001%, Cr≤0.001%, Si≤0.003%, Mo≤0.005%, V≤0.001%, O≤0.03%, N≤0.003%, and C≤0.02%.

[0040] The plates made in the above Examples 1, 2 and 3 were compared with the data of the mass percentages of elements contained in three different positions of the plates. Among them, the element content range of Example 3, especially the oxygen and impurity content range, was more uniform in composition, and the oxygen content and impurity content were lower through the second smelting, thereby obtaining a high-purity hafnium-nickel alloy with a purity better than 99.9%.

[0041] Comparative Example 3 According to the preparation process of Example 3, the electron beam melting furnace was replaced with a vacuum induction furnace. The performance data of the obtained electron beam melting furnace and the vacuum induction furnace were compared as shown in the following table: Case Example 3 Comparative Example 3 project Electron beam melting furnace Induction furnace Surface smoothness Increase by 5% Reduce by 1% quality Increase by 15% Increase by 1.1% Production costs 4.3% reduction Reduced by 0.51% Material waste 2.9% reduction Not reduced Cleaning time 1-2 hours 1-2 days Product yield 97%~99% 90% Product Purity 99.9% 87% Alloy residues from molten metal adhering to the furnace wall None (no residue) Yes (residual 3.41%) Difficulty of cleaning 5% reduction Increase by 10% The advantages of using an electron beam melting furnace to prepare a high-purity hafnium-nickel alloy in the present invention are: (1) The yield of finished products melted by vacuum induction furnace is about 90%, while the yield of finished products melted by electron beam melting furnace of this technology reaches 97% to 99%; (2) When using a vacuum induction furnace for smelting, the surface of the smelted product has many impurities and needs surface finishing. However, when using the electron beam horizontal furnace smelting in this technology, the surface is smooth and has better appearance quality, which eliminates the process of surface finishing, reduces production costs and reduces material waste. (3) Before using a vacuum induction furnace for smelting, a crucible needs to be prepared and baked. The crucible also needs to be completely dried before it can be used. The crucible processing time takes 1 to 2 days. This technology uses an electron beam melting furnace. It only needs to clean the furnace, crystallizer and gun barrel in the electron beam furnace before smelting. The cleaning time only takes 1 to 2 hours. (4) When using a vacuum induction furnace, alloy residues will stick to the furnace wall of the molten metal during the smelting process, and these residues are difficult to clean. The presence of slag on the furnace wall will affect the purity of subsequent metal smelting and seriously reduce the yield of the product. This technology uses an electron beam melting furnace to overcome the disadvantage of metal liquid splashing during the induction furnace smelting process, thereby increasing the product yield by more than 7% and the product purity to 99.9%.

[0042] Based on the above data, the present invention adopts vacuum electron beam horizontal furnace smelting technology to reduce the cost of preparing high-purity hafnium-nickel alloy by controlling the purity of raw materials and smelting parameters. The raw materials of the alloy are 96% pure hafnium sponge and 99.99% pure nickel plate that meet the YS / T399-2013 standard. The vacuum degree is better than 10 —3 Pa electron beam horizontal furnace melting, the superheat temperature during melting is high, and the liquid state is maintained for a long time, so that the refining and purification process of the material can be fully and effectively carried out. At the same time, the high vacuum environment allows the main processes of degassing, decomposition, deoxidation, volatilization of metal impurities and floating of infusible impurities in the melting process to be fully carried out, so that high-purity hafnium nickel alloy with a purity of more than 99.9% can be directly prepared at low cost using low-cost sponge hafnium.

[0043] In the above-mentioned method for preparing high-purity hafnium-nickel alloy, the raw materials used are all commercially available, the equipment used are all well-known chemical equipment, and the process operation methods used are all well known to those skilled in the art.

[0044] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-purity hafnium-nickel alloy, characterized in that: The raw materials of the alloy and their mass percentages are: 88% to 92% of hafnium and 8% to 12% of nickel.

2. A high purity hafnium nickel alloy according to claim 1, characterized in that: The purity of the nickel is 99.99%, the particle size of the nickel particles is 10-20 mm, and the original nickel blank is a plate material, which is cut into particle blocks of 10-20 mm for standby use.

3. The high-purity hafnium-nickel alloy according to claim 1, characterized in that: The hafnium is sponge hafnium, the purity of which meets the YS / T 399-2013 standard, and the particle size of the sponge hafnium particles is 10 to 25 mm.

4. A method for preparing a high-purity hafnium-nickel alloy, characterized in that: The high-purity hafnium-nickel alloy raw material according to claim 1 is prepared according to the mass percentage, comprising the following preparation steps: Step 1: Raw material configuration: prepare alloy raw materials according to the ratio of 88% to 92% hafnium to 8% to 12% nickel by mass, and divide all the hafnium into two equal parts by mass to complete the raw material configuration; Step 2: Loading the raw materials into the furnace: Load the raw materials from the first step into the electron beam horizontal melting furnace in three layers, close the furnace door and start vacuuming to complete the loading of raw materials into the furnace; Step 3: First vacuum electron beam melting: using a horizontal electron beam melting furnace to perform vacuum electron beam melting, including preparation before melting, melting process and parameter adjustment; Step 4: Second vacuum electron beam melting: Turn over the plate obtained in the third step, turn the head of the plate into the tail, and perform a second melting to obtain a high-purity hafnium-nickel alloy product.

5. The method for preparing a high-purity hafnium-nickel alloy according to claim 4, characterized in that: The process of dividing the raw materials into three layers in step 2 is as follows: in the first layer, one of the two equal parts of the hafnium sponge particles is evenly dispersed and laid in a cleaned copper crucible without impurities; in the second layer, nickel particles are evenly dispersed and arranged on the hafnium sponge particles in the first layer; and in the third layer, the other of the two equal parts of the hafnium sponge particles is evenly dispersed and laid on the nickel particles in the second layer.

6. The method for preparing a high-purity hafnium-nickel alloy according to claim 4, characterized in that: Preparation and parameter adjustment before the first vacuum electron beam melting in step 3: S1.

1. Preheat the horizontal electron beam melting furnace and evacuate it at the same time. When the vacuum degree in the horizontal electron beam melting furnace is lower than 5×10 -2 Pa, start cathode heating for 5 to 10 minutes; S1.

2. After the cathode is heated, adjust and focus the electron beam position so that the emission current range of the electron gun is 0.5 to 3A; S1.3, adjust the scanning pattern again, widen a small dot of the electron beam emitted from the center of the crucible to 10-20cm horizontally, and slowly increase the emission current to 3.5-4A; S1.

4. Finally, adjust the electron beam to the starting melting position of the crucible and 2 cm away from the top of the crucible molten pool.

7. The method for preparing a high-purity hafnium-nickel alloy according to claim 6, characterized in that: The first vacuum electron beam melting process and parameter adjustment in step three are as follows: after the preparatory work before melting is completed, melting is started from the top position, and the melting is scanned toward the tail end at a speed of 0.6-0.7 mm / s. During the melting process, the electron beam stays in the molten pool for 3-5 seconds to melt the raw materials thoroughly, and the melting is continued until the tail end of the crucible molten pool is finished to obtain a preliminarily formed plate.

8. The method for preparing a high-purity hafnium-nickel alloy according to claim 7, characterized in that: After the first vacuum electron beam melting is completed, the initially formed plate is cooled for 1 to 3 hours and then taken out of the furnace to obtain a plate melted by the first vacuum electron beam melting.

9. The method for preparing a high-purity hafnium-nickel alloy according to claim 4, characterized in that: The second vacuum electron beam melting process in step 4 is as follows: the second melting will repeat the steps of the first melting; the beam is drawn from 10 to 20 cm away from the head of the crucible; after the beam is drawn normally, the electron beam is widened to 10 to 20 cm from the head of the crucible molten pool, and the electron beam is scanned and melted toward the tail end at a speed of 0.6 to 0.7 mm / s. The technical parameters of other operations are the same as those of the third step, and a preliminarily formed high-purity hafnium-nickel alloy is obtained.

10. The method for preparing a high-purity hafnium-nickel alloy according to claim 9, characterized in that: After the second vacuum electron beam melting is completed, the initially formed high-purity hafnium-nickel alloy is cooled for 1 to 3 hours and then taken out of the furnace to obtain a high-purity hafnium-nickel alloy product.

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