A method for low-temperature and high-efficiency preparation of Ti5Si3 alloy

Abstract

This invention relates to a method for low-temperature and high-efficiency preparation of Ti5Si3 alloy, belonging to the field of alloy material preparation technology. The invention involves uniformly mixing Ti material, Si material, and a third-component metal material X (X: Al, Cu, Sn, Ga, or Mn), then heating and melting the mixture under vacuum conditions for 1-2 hours to allow volatile impurities to fully volatilize and be removed, forming a homogeneous Ti-Si-X alloy melt. Under vacuum conditions, the Ti-Si-X alloy melt undergoes electromagnetic induction directional solidification phase separation and purification to obtain a Ti-Si-X alloy ingot. The Ti-Si-X alloy ingot is sequentially separated into Ti5Si3 alloy, X-Ti-Si alloy, and an impurity-enriched phase. The Ti5Si3 alloy, X-Ti-Si alloy, and impurity-enriched phase in the Ti-Si-X alloy ingot are then cut along the phase interface to obtain Ti5Si3 alloy and X-Ti-Si alloy, with the impurity-enriched phase removed. This invention can achieve the goal of preparing Ti5Si3 alloy at low temperature and high efficiency. The by-products Al-Si-Ti, Cu-Si-Ti, Sn-Si-Ti, Ga-Si-Ti or Mn-Si-Ti alloy can be recycled and reused. This technology has the characteristics of being clean, efficient and low cost.

Description

Technical Field

[0001] This invention relates to a method for preparing Ti5Si3 alloy at low temperature and with high efficiency, belonging to the field of alloy material preparation technology. Background Technology

[0002] With the increasing demands on material performance from modern technology, high-performance intermetallic silicides are attracting growing attention from researchers and are being widely applied in defense and industrial fields. In the Ti-Si system, the intermetallic compound Ti5Si3 possesses excellent physical and mechanical properties, such as a high melting temperature (2130.8℃) and low density (4.32 g / cm³). 3 It possesses high electrical and thermal properties, exhibiting excellent electrical conductivity, thermal conductivity, and high-temperature oxidation resistance. Furthermore, it is widely used in high-temperature structural materials, high-temperature antioxidant materials, microelectronics, medical applications, and jewelry manufacturing, such as high-temperature engines and fasteners for aerospace and marine applications, high-temperature antioxidant coatings for metal surfaces, and bioactive glass coatings.

[0003] Currently, the main methods for preparing Ti5Si3 include powder metallurgy (PM), mechanical alloying (MA), self-propagating high-temperature synthesis (SHS), and arc melting (AM). Powder metallurgy-prepared Ti5Si3 typically suffers from low alloy density and high porosity, leading to reduced strength and toughness. Mechanical alloying, however, results in low purity Ti5Si3 due to contamination from the ball milling media and atmosphere, requiring further purification. While SHS is considered an effective method for Ti5Si3 preparation, the extensive phase precipitation and structural transformation during the SHS process result in numerous intermediate phases in the prepared Ti5Si3 alloy, reducing its performance. The preparation of Ti5Si3 by electric arc melting suffers from problems such as high energy consumption, coarse microstructure, and non-uniform composition. Multiple melting processes are typically required to achieve uniform composition, increasing both cost and energy consumption. Furthermore, the high melting temperature of Ti5Si3 alloy (2130.8℃) leads to reactions between the alloy melt and the refractory material (container), causing severe corrosion (this not only contaminates the Ti5Si3 alloy but also shortens the service life of the refractory material). On the other hand, most of the aforementioned methods use high-purity titanium and high-purity silicon as raw materials for Ti5Si3 preparation, further increasing costs.

[0004] It is evident that current processes for producing Ti5Si3 mostly suffer from problems such as high cost and high temperature, difficulty in process control (leading to the formation of other Ti-Si intermediate phases), low purity of alloy products, and non-uniform composition. Therefore, the preparation of high-purity, uniform, and dense Ti5Si3 alloys at low temperatures remains a challenge. Summary of the Invention

[0005] To address the problems of high cost and temperature, difficulty in process control (leading to the formation of other Ti-Si intermediate phases), low purity of alloy products, and non-uniform composition in existing technologies, this invention provides a method for the low-temperature and efficient preparation of Ti5Si3 alloys. This invention uses a third low-melting-point metal X (X: Al, Cu, Sn, Ga, or Mn) as a flux to lower the melting point of the alloy melt and the crystallization temperature of Ti5Si3. Then, based on the crystallization principle of the Ti-Si-X ternary phase diagram, a vacuum-controlled electromagnetic induction directional solidification furnace is used to perform phase separation and purification of the Ti-Si-X melt, directly preparing a high-purity, homogeneous, and dense Ti5Si3 alloy at low temperature.

[0006] An economical method for preparing Ti5Si3 alloy at low temperature and with high efficiency, comprising the following steps:

[0007] (1) After uniformly mixing Ti material, Si material and third element metal material X, heat and melt them under vacuum conditions, and keep the temperature constant for 1-2 hours to allow volatile impurities to fully volatilize and be removed, forming a uniform Ti-Si-X alloy melt; wherein the third element metal X is Al, Cu, Sn, Ga or Mn metal;

[0008] (2) Under vacuum conditions, Ti-Si-X alloy melt is subjected to electromagnetic induction directional solidification phase separation and purification to obtain Ti-Si-X alloy ingot, wherein the Ti-Si-X alloy ingot includes Ti5Si3 alloy, X-Ti-Si alloy and impurity enrichment phase from bottom to top.

[0009] (3) The Ti5Si3 alloy, X-Ti-Si alloy and impurity-enriched phase in the Ti-Si-X alloy ingot are cut along the phase interface to obtain the Ti5Si3 alloy, X-Ti-Si alloy and impurity-enriched phase. The impurity-enriched phase is removed and the X-Ti-Si alloy is returned to step (1) to replace the third group of elemental metal materials to realize its recycling and reuse.

[0010] In step (1), the titanium material is low-purity titanium or low-purity Ti5Si3 material, such as sponge titanium, Ti5Si3 alloy prepared by molten salt electrolysis, Ti5Si3 alloy prepared by silicon reduction of titanium-containing slag, and Ti5Si3 alloy recycled material, etc.; the silicon material is low-purity silicon, such as secondary silicon resources extracted from diamond wire cutting silicon waste and refined silicon slag, waste solar cell silicon wafers, waste electronic silicon wafers, and industrial silicon, etc.

[0011] The amount of the third element metal material added in step (1) is as follows: Al accounts for 15-45% of the total mass of the alloy, Cu accounts for 15-40% of the total mass of the alloy, Sn accounts for 10-35% of the total mass of the alloy, Ga accounts for 5-30% of the total mass of the alloy, and Mn accounts for 10-25% of the total mass of the alloy.

[0012] The conditions for electromagnetic directional solidification in step (2) are: electromagnetic directional solidification temperature is 1400℃-1600℃, and the moving speed of Ti-Si-X alloy melt or induction coil is 1μm / s-5μm / s.

[0013] The vacuum degree in steps (1) and (2) is 0.1 Pa to 10 Pa.

[0014] The principle of low-temperature and high-efficiency preparation of Ti5Si3 alloy:

[0015] (1) The addition of low-melting-point flux X can lower the melting point of the alloy and the crystallization temperature of Ti5Si3; correspondingly, the temperature required for directional solidification phase separation to prepare Ti5Si3 alloy can be significantly reduced, effectively avoiding the erosion of refractory materials and contamination of Ti5Si3 alloy by the alloy melt, while reducing energy consumption. The phase separation of Ti5Si3 alloy during directional solidification strictly follows the crystallization principle of the Ti-Si-X ternary phase diagram, which effectively avoids the precipitation of other Ti-Si intermediate phases in the alloy, making the alloy composition uniform and dense. In addition, the composition of Ti-Si-X alloy melt is determined based on the Ti5Si3 liquid phase region with a lower crystallization temperature in the Ti-Si-X ternary phase diagram, which ensures that Ti5Si3 alloy preferentially precipitates at the bottom of the alloy.

[0016] (2) The decrease in the alloy melting point (due to the addition of flux X) will reduce the segregation coefficient of impurities in the Ti5Si3 alloy. This strengthens the segregation effect of impurities at the solid / liquid interface during directional solidification, causing more impurities to be continuously transferred from the Ti5Si3 alloy to the liquid phase, thus improving the purity of the Ti5Si3 alloy. On the other hand, the vacuum applied during alloy melting and directional solidification not only prevents the alloy from being oxidized (Ti, Si, and Al have a strong affinity for oxygen), but also further reduces the alloy melting point, thereby further strengthening the segregation effect of impurities. Ultimately, these impurities will be enriched at the top of the last solidified alloy due to segregation and be cut off. Mg and Ca impurities in the alloy have high saturated vapor pressures and are easily volatilized. Vacuum enhances the volatilization of these impurities during the heat preservation process, thereby removing more Mg and Ca impurities.

[0017] Ultimately, a high-purity, uniform, and dense Ti5Si3 alloy was prepared. The method of this invention can not only prepare Ti5Si3 alloy at low temperatures, but also is clean, efficient, and low-cost, and has obvious prospects for industrialization.

[0018] The beneficial effects of this invention are:

[0019] (1) The present invention adds a third low-melting-point metal as a flux (refining agent) for the separation and preparation of Ti5Si3 alloy, which reduces the crystallization (preparation) temperature of Ti5Si3 alloy in the electromagnetic directional solidification process, significantly reducing energy consumption and cost; in addition, the reduction in temperature also avoids the erosion of refractory materials by alloy melt and the contamination of Ti5Si3 alloy by refractory materials, and extends the service life of refractory materials.

[0020] (2) This invention uses the crystallization principle of the Ti-Si-X ternary phase diagram to separate and prepare Ti5Si3, which ensures the formation of a single, uniform, and dense Ti5Si3 alloy and avoids the formation of other Ti-Si intermediate phases in the Ti5Si3 alloy; the separated X-Ti-Si alloy can be recycled as a flux (refining agent). Therefore, the process of preparing Ti5Si3 alloy is efficient and sustainable;

[0021] (3) This invention utilizes the segregation effect of impurities at the solid / liquid interface and removes them by volatility. The addition of flux X enhances the segregation of impurities, and the application of vacuum enhances the volatilization of impurities. Therefore, the impurity removal process is efficient, simple and clean.

[0022] (4) This invention uses low-purity titanium silicon materials as raw materials to prepare high-value-added Ti5Si3 alloys. Therefore, this technical route has obvious economic advantages. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the process of the present invention;

[0024] Figure 2 This is a cross-sectional view of the alloy ingot from Example 1;

[0025] Figure 3 The image shows the microstructure of the lower Ti5Si3 alloy and the upper Al-Ti-Si alloy in Example 1.

[0026] Figure 4 This is a cross-sectional view of the alloy ingot from Example 2;

[0027] Figure 5 This is a microstructure diagram of the lower Ti5Si3 alloy and the upper Cu-Ti-Si alloy in Example 2. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0029] Example 1: A method for low-temperature and high-efficiency preparation of Ti5Si3 alloy (see Figure 1 The specific steps are as follows:

[0030] (1) After mixing industrial silicon with a purity of 99.1%, sponge titanium with a purity of 99.6%, and metallic aluminum with a purity of 99.5% (according to the low-temperature crystallization liquid phase region of Ti5Si3 in the Ti-Si-Al phase diagram, the mass ratio of sponge titanium, industrial silicon, and metallic aluminum is 55:15:30), the mixed metal material is heated to 1400℃ under a vacuum of 0.1Pa using electromagnetic induction to form a Ti-Si-Al melt and is kept at a constant temperature for 2h to allow volatile impurities to fully volatilize and form a uniform Ti-Si-Al melt.

[0031] (2) The Ti-Si-Al melt was subjected to electromagnetic induction directional solidification phase separation and purification at a pull-down rate of 1 μm / s. After directional solidification, the Ti-Si-Al alloy was separated from bottom to top into Ti5Si3, Al-Ti-Si alloy and impurity-enriched phase (see...). Figure 2 );

[0032] (3) After cutting and separating the Ti-Si-Al alloy ingot along the phase separation interface, Ti5Si3 alloy and Al-Ti-Si alloy with a purity of 99.7% were obtained (see...). Figure 3 The impurity-enriched phase was removed, and the preparation of high-purity Ti5Si3 alloy was achieved.

[0033] Example 2: A method for low-temperature and high-efficiency preparation of Ti5Si3 alloy (see Example 2) Figure 1 The specific steps are as follows:

[0034] (1) After mixing 99.0% pure low-purity silicon (extracted from silicon waste from diamond wire cutting), 99.3% sponge titanium and 99.5% metallic copper evenly (according to the low-temperature crystallization liquid phase region of Ti5Si3 in the Ti-Si-Cu phase diagram, the mass ratio of sponge titanium, low-purity silicon and copper is 60:15:25), the mixed metal material is heated to 1500℃ under a vacuum of 1Pa by electromagnetic induction to form Ti-Si-Cu melt and smelted for 1.5h to allow volatile impurities to fully volatilize and form a uniform Ti-Si-Cu melt.

[0035] (2) The Ti-Si-Cu melt was subjected to electromagnetic induction directional solidification phase separation and purification at a pull-down rate of 5 μm / s. After directional solidification, the Ti-Si-Cu alloy was separated from bottom to top into Ti5Si3, Cu-Ti-Si alloy and impurity-enriched phase (see...). Figure 4 );

[0036] (3) After cutting and separating the Ti-Si-Al alloy ingot along the phase separation interface, Ti5Si3 alloy and Cu-Ti-Si alloy with a purity of 99.1% were obtained (see...). Figure 5 The impurity-enriched phase was removed, and the preparation of high-purity Ti5Si3 alloy was achieved.

[0037] Example 3: A method for low-temperature and high-efficiency preparation of Ti5Si3 alloy (see Example 4) Figure 1 The specific steps are as follows:

[0038] (1) After mixing Ti5Si3 alloy with a purity of 98.3% (prepared by molten salt electrolysis of titanium-containing slag) and 99.7% metallic aluminum evenly (according to the low-temperature crystallization liquid phase region of Ti5Si3 in the Ti-Si-Al phase diagram, the mass ratio of Ti5Si3 alloy to aluminum is 75:25), the mixed metal material is heated to 1550℃ under a vacuum of 5Pa by electromagnetic induction to form Ti-Si-Al melt and smelted for 1h to allow volatile impurities to fully volatilize and form a uniform Ti-Si-Al melt;

[0039] (2) The Ti-Si-Al melt was subjected to electromagnetic induction directional solidification phase separation and purification at a pull-down rate of 2 μm / s. After directional solidification, the Ti-Si-Al alloy was separated from bottom to top into Ti5Si3, Al-Ti-Si alloy and impurity enrichment phase.

[0040] (3) After cutting and separating the Ti-Si-Al alloy ingot along the phase interface, Ti5Si3 alloy and Al-Ti-Si alloy with a purity of 99.2% were obtained. The impurity enriched phase was removed, and the preparation of high-purity Ti5Si3 alloy was realized.

[0041] Example 4: A method for low-temperature and high-efficiency preparation of Ti5Si3 alloy (see Example 4) Figure 1 The specific steps are as follows:

[0042] (1) After mixing Ti5Si3 alloy with a purity of 97% (prepared by silicon reduction of titanium-containing slag) and 99.7% metallic copper evenly (according to the low-temperature crystallization liquid phase region of Ti5Si3 in the Ti-Si-Cu phase diagram, the mass ratio of Ti5Si3 alloy to copper is 70:30), the mixed metal material is heated to 1550℃ under a vacuum of 0.1Pa using electromagnetic induction to form Ti-Si-Cu melt and smelted for 2h to allow volatile impurities to fully volatilize and form a uniform Ti-Si-Cu melt;

[0043] (2) The Ti-Si-Cu melt was subjected to electromagnetic induction directional solidification phase separation and purification at a pull-down rate of 1 μm / s. After directional solidification, the Ti-Si-Cu alloy was separated from bottom to top into Ti5Si3, Cu-Ti-Si alloy and impurity enrichment phase.

[0044] (3) After cutting and separating the Ti-Si-Al alloy ingot along the phase interface, Ti5Si3 alloy and Cu-Ti-Si alloy with a purity of 99.5% were obtained. The impurity enrichment phase was removed, and the preparation of high-purity Ti5Si3 alloy was realized.

[0045] Example 5: A method for low-temperature and high-efficiency preparation of Ti5Si3 alloy (see Example 5) Figure 1 The specific steps are as follows:

[0046] (1) After mixing low-purity silicon (extracted from silicon slag) with a purity of 98.5%, sponge titanium with a purity of 99.1% and metallic manganese with a purity of 99.5% evenly (according to the low-temperature crystallization liquid phase region of Ti5Si3 in the Ti-Si-Mn phase diagram, the mass ratio of sponge titanium, low-purity silicon and manganese is 55:25:20), the mixed metal material is heated to 1600℃ under a vacuum of 10Pa by electromagnetic induction to form Ti-Si-Mn melt and smelted for 1h to allow volatile impurities to fully volatilize and form a uniform Ti-Si-Mn melt;

[0047] (2) The Ti-Si-Mn melt was subjected to electromagnetic induction directional solidification phase separation and purification at a pull-down rate of 4 μm / s. After directional solidification, the Ti-Si-Mn alloy was separated from bottom to top into Ti5Si3, Mn-Ti-Si alloy and impurity-enriched phase.

[0048] (3) After cutting and separating the Ti-Si-Al alloy ingot along the phase interface, Ti5Si3 alloy and Mn-Ti-Si alloy with a purity of 98.8% were obtained. The impurity enriched phase was removed, and the preparation of high-purity Ti5Si3 alloy was realized.

[0049] Example 6: A method for low-temperature and high-efficiency preparation of Ti5Si3 alloy (see Example 6) Figure 1 The specific steps are as follows:

[0050] (1) After mixing low-purity silicon (waste solar cell silicon wafer recycling material) with a purity of 99.8%, sponge titanium with a purity of 99.7%, and metallic tin with a purity of 99.5% evenly (according to the low-temperature crystallization liquid phase region of Ti5Si3 in the Ti-Si-Sn phase diagram, the mass ratio of sponge titanium, industrial silicon, and aluminum is 60:20:20), the mixed metal material is heated to 1450℃ under a vacuum of 0.1Pa using electromagnetic induction to form a Ti-Si-Sn melt and smelted for 2 hours to allow volatile impurities to fully volatilize and form a uniform Ti-Si-Sn melt;

[0051] (2) The Ti-Si-Sn melt was subjected to electromagnetic induction directional solidification phase separation and purification at a pull-down rate of 3 μm / s. After directional solidification, the Ti-Si-Sn alloy was separated from bottom to top into Ti5Si3, Sn-Ti-Si alloy and impurity-enriched phase.

[0052] (3) After cutting and separating the Ti-Si-Sn alloy ingot along the phase interface, Ti5Si3 alloy and Sn-Ti-Si alloy with a purity of 99.3% were obtained. The impurity enriched phase was removed, and the preparation of high-purity Ti5Si3 alloy was realized.

[0053] Example 7: A method for low-temperature and high-efficiency preparation of Ti5Si3 alloy (see Example 7) Figure 1 The specific steps are as follows:

[0054] (1) After mixing low-purity silicon (waste electronic silicon wafer recycling material) with a purity of 99.9%, sponge titanium with a purity of 99.5%, and metallic gallium with a purity of 99.9% evenly (according to the low-temperature crystallization liquid phase region of Ti5Si3 in the Ti-Si-Ga phase diagram, the mass ratio of sponge titanium, low-purity silicon, and gallium is 65:20:15), the mixed metal material is heated to 1400℃ under a vacuum of 10Pa using electromagnetic induction to form a Ti-Si-Ga melt and smelted for 1.5h to allow volatile impurities to fully volatilize and form a uniform Ti-Si-Ga melt;

[0055] (2) The Ti-Si-Ga melt was subjected to electromagnetic induction directional solidification phase separation and purification at a pull-down rate of 3 μm / s. After directional solidification, the Ti-Si-Ga alloy was separated from bottom to top into Ti5Si3, Ga-Ti-Si alloy and impurity-enriched phase.

[0056] (3) After cutting and separating the Ti-Si-Ga alloy ingot along the phase interface, Ti5Si3 alloy and Ga-Ti-Si alloy with a purity of 99.5% were obtained. The impurity enriched phase was removed, and the preparation of high-purity Ti5Si3 alloy was realized.

[0057] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing Ti5Si3 alloy at low temperature and with high efficiency, characterized in that, The specific steps are as follows: (1) After uniformly mixing Ti material, Si material and third element metal material X, heat and melt them under vacuum conditions, and keep the temperature constant for 1~2h to allow volatile impurities to fully volatilize and be removed, forming a uniform Ti-Si-X alloy melt; wherein the third element metal material X is Al, Cu, Sn, Ga or Mn metal; (2) Under vacuum conditions, Ti-Si-X alloy melt is subjected to electromagnetic induction directional solidification phase separation and purification to obtain Ti-Si-X alloy ingot, wherein the Ti-Si-X alloy ingot includes Ti5Si3 alloy, X-Ti-Si alloy and impurity enrichment phase from bottom to top; the electromagnetic induction directional solidification temperature is 1450℃-1600℃, and the moving speed of Ti-Si-X alloy melt or induction coil is 1μm / s-5μm / s; (3) The Ti5Si3 alloy, X-Ti-Si alloy and impurity-enriched phase in the Ti-Si-X alloy ingot are cut along the phase interface to obtain the Ti5Si3 alloy, X-Ti-Si alloy and impurity-enriched phase. The impurity-enriched phase is removed and the X-Ti-Si alloy is returned to step (1) to replace the third group of elemental metal materials.

2. The method for preparing Ti5Si3 alloy at low temperature and high efficiency according to claim 1, characterized in that: In step (1), the titanium material is low-purity titanium or low-purity Ti5Si3 material, and the silicon material is low-purity silicon.

3. The method for preparing Ti5Si3 alloy at low temperature and high efficiency according to claim 1, characterized in that: Step (1) The amount of Al added accounts for 15-45% of the total mass of the alloy, the amount of Cu added accounts for 15-40% of the total mass of the alloy, the amount of Sn added accounts for 10-35% of the total mass of the alloy, the amount of Ga added accounts for 5-30% of the total mass of the alloy, and the amount of Mn added accounts for 10-25% of the total mass of the alloy.

4. The method for preparing Ti5Si3 alloy at low temperature and high efficiency according to claim 1, characterized in that: The vacuum degree in steps (1) and (2) is 0.1 Pa to 10 Pa.

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