Growth method of alloy metal single crystal

Abstract

The invention discloses a growth method of an alloy metal single crystal, which comprises the following steps: loading an alloy raw material containing a target alloy metal single crystal into a crucible, placing the crucible in a vacuum furnace, purifying the atmosphere in the vacuum furnace, and filling protective gas; heating until the alloy raw material is fully molten, filling set gas to normal pressure, and keeping the temperature to enable the molten liquid to reach a saturated state; cooling at a set cooling rate to form crystals on the surface of the melt; and naturally cooling to room temperature, taking out the crucible, and transferring and treating the surface crystal to obtain the alloy metal single crystal. A set gas is introduced into alloy melt or a crucible material is used for dissolution, two-dimensional single crystals are formed on the surface of the melt in the cooling process, and the two-dimensional single crystals serve as a template to induce metal single crystals to grow from the surface. The method is simple in principle, novel and easy to operate.

Description

Technical Field

[0001] This invention belongs to the field of single crystal material growth technology, and more specifically, relates to a method for growing alloy metal single crystals. Background Technology

[0002] Alloy metal single crystals occupy a leading and strategic position in materials science and engineering, possessing irreplaceable strategic significance for national defense, aerospace, and energy security. They represent one of the limits of structural material design and are core foundational materials for high-end equipment in aerospace, energy industries, and other sectors. The core characteristics of alloy metal single crystals are their excellent mechanical properties; for example, nickel-based single crystals exhibit high yield strength in the

[001] direction, anisotropy, and excellent high-temperature oxidation and corrosion resistance. The applications of alloy metal single crystals are highly concentrated in fields with extremely demanding performance requirements. The most important and successful application is in the manufacture of high-pressure turbine blades and guide vanes for aero-engines and gas turbines.

[0003] Currently, the preparation of alloy single crystals usually adopts the crystal selection method or seed crystal method in directional solidification. Both require precise control of temperature gradient, solidification rate and crystal orientation. Due to the high difficulty of preparation and relatively low yield, alloy single crystal components are very expensive and are usually only used in critical parts with extremely demanding performance requirements. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a simple method for growing alloy metal single crystals.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for growing a single crystal of an alloy metal, comprising: Step 1: The alloy raw material containing the target alloy metal single crystal is loaded into a crucible, the crucible is placed in a vacuum furnace, the atmosphere inside the vacuum furnace is purified, and a protective gas is introduced. Step 2: Heat until the alloy raw material is fully melted, introduce the set gas to atmospheric pressure, and hold the temperature until the melt reaches saturation; Step 3: Cool the melt at the set cooling rate to allow crystals to begin forming on the surface of the melt. Step 4: Allow the mixture to cool naturally to room temperature, remove the crucible, transfer the surface crystals, and obtain the alloy metal single crystal.

[0006] In step one, the crucible undergoes pretreatment before use, which involves baking it in an oven at 150±5℃.

[0007] In a preferred embodiment, step one, the process of purifying the atmosphere inside the vacuum furnace, includes evacuating to a vacuum level of 1×10⁻⁶. - 4Below 30 kPa, fill with high-purity argon gas to atmospheric pressure, repeat 3-5 times, and finally fill with high-purity argon gas at 30-50 kPa.

[0008] In a preferred embodiment, the set gas is one of nitrogen, argon and hydrogen sulfide or a mixture thereof.

[0009] In a preferred embodiment, the cooling rate is 3-5°C / min.

[0010] As a preferred embodiment, the surface crystal transfer method in step four is mechanical peeling or chemical etching.

[0011] In a preferred embodiment, the alloy raw materials include Fe, Ni and B, or Cu and Al, or Au and Mo.

[0012] In a preferred embodiment, the crucible is a corundum crucible, a graphite crucible, or a pBN crucible.

[0013] The alloy metal single crystal growth method provided by this invention involves slowly cooling a molten metal alloy under the condition of introducing a predetermined gas. Due to the reaction of the predetermined gas with certain elements in the molten metal, or the saturation precipitation of crucible material dissolved in the molten metal during cooling, two-dimensional single crystal materials nucleate and grow. These floating two-dimensional single crystals exhibit equilateral triangles or regular hexagons and remain in a floating state during growth. During mutual contact, their edges spontaneously align, ultimately forming quasi-single crystal edges covering the surface of the molten metal. Further cooling ensures the molten metal surface temperature is kept to a minimum, causing surface crystallization to occur first. During the slow cooling process, metal single crystals crystallize from the surface. The alloy metal single crystal is obtained by transferring the crystals from the sample surface. This method is simple in principle, novel in approach, and easy to operate. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the vacuum furnace growth apparatus according to an embodiment of the present invention; in the figure, 1-crucible, 2-graphite heater, 3-graphite felt, 4-molten liquid, 5-heating coil.

[0015] Figure 2 This is a topographic image of the surface before the h-BN crystals were transferred in Example 1.

[0016] Figure 3 This is a morphology image of the surface h-BN crystal after transfer in Example 1.

[0017] Figure 4 This is an optical microscope image of the metal surface in Example 1. Detailed Implementation

[0018] The basic concept of this invention is to introduce a predetermined gas into the alloy melt or to dissolve the crucible material, and to form a two-dimensional single crystal on the surface of the melt during the cooling process, and to use this as a template to induce the growth of metal single crystals from the surface.

[0019] Based on this, a typical embodiment of the present invention provides a method for growing alloy metal single crystals, including steps one to four.

[0020] Step 1: Vacuum environment purification and gas protection.

[0021] The alloy raw material containing the target alloy metal single crystal is loaded into a crucible, which is then placed in a vacuum furnace. The atmosphere inside the vacuum furnace is purified and filled with a protective gas.

[0022] The crucible undergoes pretreatment before use, which involves baking it in an oven at 150±5°C. For example, the crucible is baked in an oven at 150°C for 120 minutes, or in an oven at 155°C for 120 minutes, or in an oven at 145°C for 120 minutes.

[0023] In a relatively specific implementation, the procedure for purifying the internal atmosphere of the vacuum furnace includes: after the furnace cavity is sealed, the vacuum pump is turned on to pump the pressure inside the vacuum furnace to 1×10⁻⁶. -4 Below 100 kPa, fill the furnace with high-purity argon gas to atmospheric pressure and repeat the operation 3-5 times; finally, fill the furnace cavity with 30-50 kPa of high-purity argon gas to prevent the evaporation of the metal flux under vacuum.

[0024] For example, the alloy raw materials include Fe, Ni and B, or Cu and Al, or Au and Mo.

[0025] For example, the crucible is a corundum crucible, a graphite crucible, or a pBN crucible.

[0026] Step two, heat and melt.

[0027] Turn on the heating system and heat until the alloy raw material is fully melted. After it is fully melted, fill the system with a set gas to atmospheric pressure and hold it at that temperature for a period of time to allow the melt to reach saturation.

[0028] In this step, the set gas is one of nitrogen, argon and hydrogen sulfide or a mixture thereof. The set gas can dissolve in the molten metal during the heat preservation process, so that the molten metal reaches a saturated state.

[0029] Step 3: Cool down for crystallization.

[0030] Cool the melt at a rate of 3-5℃ / min to allow crystals to begin forming on the surface of the melt.

[0031] During the slow cooling process, due to the reaction of the set gas with some elements in the molten metal or the dissolution of the crucible material in the molten metal, saturation precipitation occurs during cooling, resulting in the nucleation and growth of two-dimensional single-crystal materials. These materials float during growth, and their edges spontaneously align during contact, ultimately forming a quasi-single-crystal state covering the surface of the molten metal. Because the surface temperature of the molten metal is the lowest, the crystallization of the single-crystal metal begins from the surface during the slow cooling process.

[0032] Step 4: Transfer surface crystals.

[0033] Turn off the power supply and allow the equipment to cool down naturally. After it has cooled to room temperature, release the gas, remove the crucible, and transfer the crystals from the surface to obtain an alloy metal single crystal.

[0034] For example, the surface crystal transfer method is mechanical peeling or chemical etching.

[0035] The technical solutions claimed in this invention will be further described below through some embodiments. However, the embodiments are for explaining the implementation of the present invention and do not exceed the scope of the subject matter of the present invention. The scope of protection of the present invention is not limited by the embodiments. Unless otherwise specified, the materials and reagents used in this invention can be obtained from commercially available products in the art.

[0036] The following examples are all in Figure 1 The vacuum furnace growth apparatus shown includes a crucible 1, a graphite heater 2, a graphite felt 3, and a heating coil 5. The graphite heater 2 is located on the innermost side of the vacuum furnace wall structure, and the crucible 1 is placed inside the graphite heater 2. The graphite felt 3 is arranged around the graphite heater 2, and the heating coil 5 is also located there. Figure 1 As shown, the raw materials inside crucible 1 melt to form molten liquid 4. Example 1

[0037] Place the corundum crucible in a 150℃ oven and bake for 120 minutes to dry it.

[0038] Add Fe, Ni, and B powders in a mass ratio of 10:1:1 to an alumina crucible, mix thoroughly, and then place the crucible into a graphite heater. Use a vacuum pump to evacuate the furnace to below 1×10⁻⁴ Pa, then purge with argon to atmospheric pressure. Repeat this process 3-5 times to purify the furnace atmosphere, remove residual background gases from the furnace cavity, and then turn off the vacuum pump.

[0039] Turn on the power and first fill the furnace cavity with 30 kPa of argon gas to prevent the evaporation of the metal flux under vacuum. Turn on the heating system and heat the crucible in the furnace until the alloy metal is fully melted and the B powder is completely dissolved in the alloy solution.

[0040] After the B powder is completely dissolved, high-purity nitrogen gas at 70 kPa is introduced into the furnace cavity to atmospheric pressure, and then the temperature is maintained for a period of time to allow the nitrogen gas to fully dissolve in the metal solution and the solution to reach saturation.

[0041] Once the melt reaches a stable saturation state, it is then slowly cooled at a rate of 4℃ / min.

[0042] Turn off the power supply and allow it to cool naturally to room temperature. After releasing the gas, remove the corundum crucible and use chemical etching to transfer the h-BN crystals on the surface (morphological images before and after h-BN crystal transfer are shown in the figure). Figure 2 and Figure 3 As shown), the transferred surface is ground and polished to obtain iron-nickel alloy metal single crystals (such as...). Figure 4 (As shown). Example 2

[0043] Place the graphite crucible in a 150℃ oven and bake for 120 minutes to dry it.

[0044] Cu and Al were placed in a graphite crucible with a molar ratio of Cu:Al of 67:33. After thorough mixing, the crucible was placed in a graphite heater. The pressure inside the furnace was evacuated to 1×10⁻⁶ using a vacuum pump. -4 The pressure is below 10 Pa, then argon is introduced to atmospheric pressure. This process is repeated 3-5 times to purify the atmosphere inside the furnace, remove residual background gas from the furnace cavity, and then the vacuum pump is turned off.

[0045] Turn on the power and first fill the furnace cavity with 30 kPa of argon gas to prevent the evaporation of the metal flux under vacuum. Turn on the heating system and heat the crucible in the furnace until the alloy metal is fully melted and the crucible material dissolves in the alloy melt.

[0046] Argon gas at 70 kPa is introduced into the furnace cavity to atmospheric pressure, and then the temperature is maintained for a period of time to saturate the molten liquid.

[0047] Once the melt reaches a stable saturation state, it is then slowly cooled at a rate of 3℃ / min.

[0048] After turning off the power supply and allowing it to cool naturally to room temperature, the graphite crucible is removed after venting. The graphite single crystal on the surface is then transferred using mechanical peeling. The transferred surface is then polished to obtain a copper-aluminum alloy metal single crystal. Example 3

[0049] Place the pBN crucible in a 150℃ oven and bake for 120 minutes to dry it.

[0050] Au and Mo were placed in a pBN crucible at a mass ratio of 1:1 and thoroughly mixed before being placed in a graphite heater. The pressure inside the furnace was then evacuated to 1 × 10⁻⁶ using a vacuum pump. -4The pressure is reduced to below 1 Pa, then argon is added back to atmospheric pressure. This process is repeated 3-5 times to purify the atmosphere inside the furnace, remove residual background gas from the furnace cavity, and then the vacuum pump is turned off.

[0051] Turn on the power and first fill the furnace chamber with 30 kPa of argon gas to prevent the metal flux from evaporating under vacuum. Then turn on the heating system to heat the crucible in the furnace until the alloy metal is fully melted.

[0052] The furnace cavity is filled with a mixture of H2S and argon at 70 kPa to atmospheric pressure, and then kept at this temperature for a period of time to allow the H2S gas to fully dissolve in the molten metal and saturate the molten metal.

[0053] Once the melt reaches a stable saturation state, it is then slowly cooled at a rate of 5℃ / min.

[0054] After turning off the power supply and allowing it to cool naturally to room temperature, the corundum crucible was removed after venting. The surface of the MoS2 quasi-single crystal was then transferred using chemical etching. The transferred surface was then polished to obtain a gold-molybdenum alloy metal single crystal.

[0055] The scope of protection claimed by this invention is not limited to the specific embodiments described above. For those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for growing single crystals of alloy metals, characterized in that, include: Step 1: The alloy raw material containing the target alloy metal single crystal is loaded into a crucible, the crucible is placed in a vacuum furnace, the atmosphere inside the vacuum furnace is purified, and a protective gas is introduced. Step 2: Heat until the alloy raw material is fully melted, introduce the set gas to atmospheric pressure, and hold the temperature until the melt reaches saturation; Step 3: Cool the melt at the set cooling rate to allow crystals to begin forming on the surface of the melt. Step 4: Allow the mixture to cool naturally to room temperature, remove the crucible, transfer the surface crystals, and obtain the alloy metal single crystal.

2. The method for growing alloy metal single crystals according to claim 1, characterized in that: In step one, the crucible undergoes pretreatment before use, which involves baking it in an oven at 150±5℃.

3. The method for growing alloy metal single crystals according to claim 2, characterized in that: Step one, the procedure for purifying the atmosphere inside the vacuum furnace includes evacuating to a vacuum level of 1×10⁻⁶. -4 Below 30 kPa, fill with high-purity argon gas to atmospheric pressure, repeat 3-5 times, and finally fill with high-purity argon gas at 30-50 kPa.

4. A method for growing an alloy metal single crystal according to claim 1, 2, or 3, characterized in that: The set gas is one of nitrogen, argon and hydrogen sulfide or a mixture thereof.

5. The method for growing alloy metal single crystals according to claim 4, characterized in that: The cooling rate is 3-5℃ / min.

6. A method for growing alloy metal single crystals according to claim 1 or 5, characterized in that: The surface crystal transfer method described in step four is mechanical peeling or chemical etching.

7. The method for growing alloy metal single crystals according to claim 1, characterized in that: The alloy raw materials include Fe, Ni and B, or Cu and Al, or Au and Mo.

8. A method for growing an alloy metal single crystal according to claim 1 or 7, characterized in that: The crucible is a corundum crucible, a graphite crucible, or a pBN crucible.

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