An HCP-type titanium-based multi-principal component composite material

Abstract

This invention relates to an HCP-type titanium-based multi-principal component composite material, belonging to the field of metallic materials technology. It solves at least one of the problems in existing titanium-based multi-principal component composite materials, namely, low high-temperature strength, long preparation process, and high processing cost. The composite material, by atomic percentage, comprises Al 14.5–19%, Zr 1.5–24.5%, Nb 0.5–17.5%, B 0.5–1.5%, O≤C+Si≤0.2%, with the balance being Ti and unavoidable impurities; wherein 19%≤Zr+Nb≤25%. The density of the HCP-type titanium-based multi-principal component composite material of this invention is <5.0 g / cm³. 3 It has a density that is more than 40% lower than that of traditional nickel-based high-temperature alloys at the same operating temperature, resulting in significant structural weight reduction. In addition, the composite material has a room temperature strength of ≥1250MPa, a plastic elongation of ≥6%, and a high temperature strength of ≥650MPa at 750℃.

Description

Technical Field

[0001] This invention relates to the field of metallic materials technology, and in particular to an HCP-type titanium-based multi-principal component composite material. Background Technology

[0002] In the field of aero-engine materials, nickel-based superalloys have an operating temperature range of 600℃ to 1150℃ and a density of 8.2 g / cm³. 3 The density of traditional titanium alloys is between 4.4 and 4.7 g / cm³. 3 These materials are commonly used as discs, blades, and casings in aero engines, but due to their insufficient structural stability and creep resistance, their long-term operating temperature is below 650℃. Traditional materials can no longer meet design requirements, and there is an urgent need for a new generation of lightweight high-temperature structural materials.

[0003] Titanium-based multi-principal alloys are a new type of titanium-based alloy designed using the concept of high-entropy alloys. They mainly include BCC-type titanium-based multi-principal alloys and HCP-type titanium-based multi-principal alloys. They typically contain three or more elements from Ti, Al, Cr, Nb, V, Zr, Sn, and Mo as the main elements. The alloys have low density and good strength and plasticity matching.

[0004] BCC-type titanium-based multi-principal alloys exhibit a significant decrease in strength at high temperatures due to their crystal structure. Based on a composite strengthening method utilizing intragranular precipitation strengthening and grain boundary strengthening phases, existing technologies have employed powder metallurgy to prepare TiAlCrNb-based titanium-based multi-principal alloys, resulting in lightweight, high-temperature composite materials with low density and high temperature resistance. However, this material production involves a lengthy preparation route and high production costs, requiring a process of "master alloy ingot preparation + powder preparation + powder mixing + hot pressing sintering + thermomechanical treatment." Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide an HCP-type titanium-based multi-principal component composite material to solve at least one of the problems of low high-temperature strength, long preparation process, and high process cost in the prior art of titanium-based multi-principal component composite materials.

[0006] In a first aspect, the present invention provides an HCP-type titanium-based multi-principal component composite material, wherein the composite material comprises, by atomic percentage, Al 14.5–19%, Zr 1.5–24.5%, Nb 0.5–17.5%, B 0.5–1.5%, O≤C+Si≤0.2%, and the balance being Ti and unavoidable impurities; wherein 19%≤Zr+Nb≤25%.

[0007] Furthermore, the matrix structure of the composite material is an HCP-type crystal structure.

[0008] Furthermore, the matrix grain size of the composite material is 25–100 μm.

[0009] Furthermore, the reinforcement of the composite material is in-situ self-generated titanium boride.

[0010] Furthermore, the reinforcement is in the form of short rods and is diffusely distributed in the matrix of the composite material.

[0011] Secondly, the present invention provides a method for preparing the above-mentioned composite material, comprising using sponge titanium, sponge zirconium, titanium-niobium master alloy, AlTiB master alloy, carbon powder and aluminum-silicon alloy as raw materials, mixing the raw materials according to the atomic percentages, and performing melting and thermomechanical treatment to obtain the HCP type titanium-based multi-principal component composite material.

[0012] Furthermore, the smelting process employs a vacuum consumable melting method, involving at least three smelting operations.

[0013] Furthermore, the melting vacuum degree is <1Pa, the equipment leakage rate is <0.5Pa / min, the melting current is 3-6kA, and the melting voltage is 25-35V.

[0014] Furthermore, the thermomechanical treatment includes at least one of forging, extrusion, or hot rolling.

[0015] Furthermore, the thermomechanical treatment involves first performing hot processing by extrusion to obtain a bar, and then performing heat treatment on the bar.

[0016] Furthermore, the extrusion temperature is 950–1150℃, the extrusion ratio is ≥10, the heat treatment temperature is 800–900℃, and the time is 0.5–3h.

[0017] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0018] (1) The density of the HCP-type titanium-based multi-principal component composite material described in this invention is <5.0 g / cm³. 3 The density of the composite material is more than 40% lower than that of traditional nickel-based high-temperature alloys at the same operating temperature, resulting in significant weight reduction. In addition, the composite material has a room temperature strength ≥1250MPa, a plastic elongation ≥6%, and a high temperature strength ≥650MPa at 750℃. The density and strength of the composite material prepared by this invention are significantly better than those of existing nickel-based high-temperature alloys, and the high temperature strength is better than that of traditional titanium alloys, which is of great significance for weight reduction in aerospace equipment.

[0019] (2) The HCP-type titanium-based multi-principal composite material of the present invention has an HCP-type crystal structure. The HCP-type crystal structure has the characteristic of resisting high-temperature softening. The HCP-type crystal structure has stronger resistance to softening at high temperature than the BCC-type crystal structure. The high-temperature strength of the alloy can be further improved by forming an in-situ self-generated reinforcement in the matrix. However, the BCC-type titanium-based multi-principal alloy requires the composite strengthening of intragranular precipitation and grain boundary strengthening phases to achieve the improvement of high-temperature strength. Moreover, the composite strengthening of intragranular precipitation and grain boundary phases requires powder metallurgy to prepare, which is a longer technical route and cycle. In contrast, the HCP-type titanium-based multi-principal composite material of the present invention has a shorter technical route, shorter production cycle, and lower process cost.

[0020] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0021] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0022] Figure 1 This is a microstructure diagram of the composite material of Example 1 of the present invention;

[0023] Figure 2 This is a phase ratio diagram of the composite material of Example 1 of the present invention;

[0024] Figure 3 This is a phase ratio diagram of the composite material of Comparative Example 3 of the present invention. Detailed Implementation

[0025] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0026] A specific embodiment of the present invention discloses an HCP-type titanium-based multi-principal component composite material, wherein the composite material comprises, by atomic percentage, Al 14.5–19%, Zr 1.5–24.5%, Nb 0.5–17.5%, B 0.5–1.5%, O≤C+Si≤0.2%, with the balance being Ti and unavoidable impurities; wherein 19%≤Zr+Nb≤25%.

[0027] The HCP-type titanium-based multi-principal composite material of the present invention has an HCP-type crystal structure. The HCP-type crystal structure has the characteristic of resisting high-temperature softening. The HCP-type crystal structure has stronger resistance to softening at high temperatures than the BCC-type crystal structure. By forming in-situ self-generated reinforcements in the matrix, the high-temperature strength of the alloy can be further improved without the need for the composite strengthening of intragranular precipitation and grain boundary strengthening phases required by the BCC-type titanium-based multi-principal alloy to achieve the improvement of high-temperature strength.

[0028] The following details the function and dosage selection of the components contained in this invention:

[0029] In this invention, Al, Zr, and Nb are indispensable elements in titanium-based multi-principal component composites. Al, Zr, and Nb elements dissolve into the HCP matrix of the alloy, achieving solid solution strengthening. Furthermore, the contents of Al, Zr, and Nb must be synergistically controlled within the range defined in this invention, which is crucial for crystal structure formation, alloy density, and the matching of strength and plasticity. Through extensive experimental research, the inventors have determined that the alloy prepared within the above-mentioned ranges (Al 14.5–19%, Zr 1.5–24.5%, Nb 0.5–17.5%, 19% ≤ Zr + Nb ≤ 25%) exhibits optimal density and strength / plasticity.

[0030] In this invention, B can react with Ti during the ingot smelting process to form in-situ self-generated titanium boride. The titanium boride is dispersed and precipitated in the matrix, which can play a strengthening role. The control of B content is crucial. When the B content is too low, the strengthening effect is not obvious. When the B content is too high, a large amount of boride in the matrix will cause the material to become brittle.

[0031] In this invention, the addition of small amounts of Si and C elements can further strengthen the alloy. The content of Si and C can be controlled in combination with that of B. In this invention, the content of Si and C can be arbitrary, as long as 0 ≤ C + Si ≤ 0.2%.

[0032] In one specific embodiment, the matrix structure of the composite material is an HCP-type crystal structure.

[0033] In one specific embodiment, the matrix grain size of the composite material is 25–100 μm.

[0034] In one specific embodiment, the reinforcement of the composite material is in-situ self-generated titanium boride.

[0035] In one specific embodiment, the reinforcement is in the form of short rods and is dispersedly distributed in the matrix of the composite material.

[0036] In one specific embodiment, the density of the composite material is <5.0 g / cm³. 3Room temperature strength ≥1250MPa, plastic elongation ≥6%, high temperature strength at 750℃ ≥650MPa.

[0037] Preferably, the density of the composite material is 4.76–4.95 g / cm³. 3 The room temperature strength is 1253-1325 MPa, the plastic elongation is 6-10%, and the strength at 750℃ is 650-702 MPa.

[0038] Another specific embodiment of the present invention discloses a method for preparing the above-mentioned HCP-type titanium-based multi-principal component composite material, comprising using sponge titanium, sponge zirconium, titanium-niobium master alloy, AlTiB master alloy, carbon powder and aluminum-silicon alloy as raw materials, mixing the raw materials according to the atomic percentage, and performing melting and thermomechanical treatment to obtain the HCP-type titanium-based multi-principal component composite material.

[0039] In one specific implementation, the melting process employs a vacuum consumable melting method, and the melting is carried out at least three times.

[0040] Specifically, the melting vacuum degree is <1Pa, the equipment leakage rate is <0.5Pa / min, the melting current is 3-6kA, and the melting voltage is 25-35V.

[0041] In one specific embodiment, the thermomechanical treatment includes at least one of forging, extrusion, or hot rolling.

[0042] In one specific embodiment, the thermomechanical treatment involves first performing heat processing by extrusion to obtain a bar, and then performing heat treatment on the bar.

[0043] Specifically, the extrusion temperature is 950–1150℃, the extrusion ratio is ≥10, the heat treatment temperature is 800–900℃, and the time is 0.5–3h.

[0044] The HCP-type titanium-based multi-principal composite material of this invention has an HCP-type crystal structure. The HCP-type crystal structure has stronger resistance to softening at high temperatures than the BCC-type crystal structure. By forming in-situ self-generated reinforcements in the matrix, the high-temperature strength of the alloy can be further improved. This is different from the requirement of intragranular precipitation and grain boundary strengthening phases in BCC-type titanium-based multi-principal alloys to achieve high-temperature strength improvement. Moreover, the composite strengthening of intragranular precipitation and grain boundaries requires powder metallurgy methods, which are more time-consuming and have a longer technical route. In contrast, the HCP-type titanium-based multi-principal composite material of this invention has a shorter technical route, shorter production cycle, and lower process cost.

[0045] It should be noted that titanium-based multi-principal alloys are usually composed of main elements such as Ti, Al, Cr, Nb, V, Zr, and Sn. The addition of β-type stabilizing elements such as Nb, Cr, V, and Zr makes it easier for the alloy to form a BCC-type crystal structure. The composition range of titanium-based multi-principal alloys that form an HCP-type crystal structure is narrower. Therefore, in the process of designing high-performance (such as low density, room temperature and high temperature strength and plasticity matching) HCP-type titanium-based multi-principal composite materials, it is more difficult to control the combination of alloying elements and the comprehensive matching of the content of each element.

[0046] Through extensive experimentation, the inventors determined the elements and their proportions, resulting in the preparation of an HCP-type titanium-based multi-principal component composite material. This composite material exhibits higher strength at high temperatures, a shorter production cycle, and lower processing costs. Furthermore, its density is <5.0 g / cm³. 3 The density of this composite material is more than 40% lower than that of traditional nickel-based superalloys used at the same temperature, resulting in significant structural weight reduction. The density of the composite material is <5.0 g / cm³. 3 Room temperature strength ≥1250MPa, plastic elongation ≥6%, high temperature strength at 750℃ ≥650MPa.

[0047] The technical solution of the present invention will be further explained below with reference to specific embodiments.

[0048] Example 1

[0049] An HCP-type titanium-based multi-principal component composite material, wherein the composite material comprises, by atomic percentage, 14.5% Al, 24.5% Zr, 0.5% Nb, 1% B, with the balance being Ti and unavoidable impurities.

[0050] The preparation method of the HCP-type titanium-based multi-principal component composite material in this embodiment is as follows:

[0051] (1) Including the use of sponge titanium, sponge zirconium, titanium niobium master alloy and AlTiB master alloy raw materials, according to the atomic percentage of each raw material, the raw materials are mixed and subjected to vacuum self-consumption melting method, melting at least three times to obtain ingot; wherein, the melting vacuum degree is <1Pa, the equipment leakage rate is <0.5Pa / min, the melting current is 3~6kA and the melting voltage is 25~35V.

[0052] (2) The ingot is hot-processed by extrusion at a temperature of 1050°C and an extrusion ratio of ≥10 to obtain a bar. The bar is then heat-treated at 850°C for 3 hours and air-cooled to obtain the HCP type titanium-based multi-principal component composite material.

[0053] The matrix grain size of the composite material in this embodiment is 25–100 μm, and the microstructure of the composite material is as follows: Figure 1As shown in the figure, the boride (TiB2) reinforcement is in the form of short rods and is dispersed in the matrix of the composite material.

[0054] The phase ratio diagram of the composite material in this embodiment was calculated using thermodynamics, as follows: Figure 2 As shown in the figure, the composite material in this embodiment contains an HCP structure and a boride reinforcement, which is consistent with the experimental results.

[0055] Example 2

[0056] An HCP-type titanium-based multi-principal component composite material, wherein the composite material comprises, by atomic percentage, 17% Al, 20% Zr, 0.5% Nb, 1% B, with the balance being Ti and unavoidable impurities.

[0057] The preparation method of the HCP-type titanium-based multi-principal component composite material in this embodiment is as follows:

[0058] (1) Including the use of sponge titanium, sponge zirconium, titanium niobium master alloy and AlTiB master alloy raw materials, according to the atomic percentage of each raw material, the raw materials are mixed and subjected to vacuum self-consumption melting method, melting at least three times to obtain ingot; wherein, the melting vacuum degree is <1Pa, the equipment leakage rate is <0.5Pa / min, the melting current is 3~6kA and the melting voltage is 25~35V.

[0059] (2) The ingot is heat-processed by extrusion at a temperature of 1000℃ and an extrusion ratio of ≥10 to obtain a bar. The bar is then heat-treated at 890℃ for 1.5h and air-cooled to obtain the HCP type titanium-based multi-principal composite material.

[0060] The matrix grain size of the composite material in this embodiment is 25-100 μm. The composite material in this embodiment was tested in Example 1, and the results were basically the same. Due to space limitations, they will not be listed one by one.

[0061] Example 3

[0062] An HCP-type titanium-based multi-principal component composite material, wherein the composite material comprises, by atomic percentage, 19% Al, 1.5% Zr, 17.5% Nb, 1.5% B, with the balance being Ti and unavoidable impurities.

[0063] The preparation method of the HCP-type titanium-based multi-principal component composite material in this embodiment is as follows:

[0064] (1) Including the use of sponge titanium, sponge zirconium, titanium niobium master alloy and AlTiB master alloy raw materials, according to the atomic percentage of each raw material, the raw materials are mixed and subjected to vacuum self-consumption melting method, melting at least three times to obtain ingot; wherein, the melting vacuum degree is <1Pa, the equipment leakage rate is <0.5Pa / min, the melting current is 3~6kA and the melting voltage is 25~35V.

[0065] (2) The ingot is hot-processed by extrusion at a temperature of 1150°C and an extrusion ratio of ≥10 to obtain a bar. The bar is then heat-treated at 980°C for 0.5 hours and air-cooled to obtain the HCP type titanium-based multi-principal composite material.

[0066] The matrix grain size of the composite material in this embodiment is 25-100 μm. The composite material in this embodiment was tested in Example 1, and the results were basically the same. Due to space limitations, they will not be listed one by one.

[0067] Example 4

[0068] An HCP-type titanium-based multi-principal component composite material, wherein the composite material comprises, by atomic percentage, 15% Al, 23% Zr, 0.5% Nb, 1% B, 0.05% Si, with the balance being Ti and unavoidable impurities.

[0069] The preparation method of the HCP-type titanium-based multi-principal component composite material in this embodiment is as follows:

[0070] (1) The method includes using sponge titanium, sponge zirconium, titanium-niobium master alloy, AlTiB master alloy and aluminum-silicon master alloy as raw materials, mixing the raw materials according to the atomic percentage and carrying out vacuum self-consumption melting, melting at least three times to obtain an ingot; wherein, the melting vacuum degree is <1Pa, the equipment leakage rate is <0.5Pa / min, the melting current is 3~6kA and the melting voltage is 25~35V;

[0071] (2) The ingot is heat-processed by extrusion at a temperature of 980°C and an extrusion ratio of ≥10 to obtain a bar. The bar is then heat-treated at 850°C for 2.5 hours and air-cooled to obtain the HCP type titanium-based multi-principal composite material.

[0072] The matrix grain size of the composite material in this embodiment is 25-100 μm. The composite material in this embodiment was tested in Example 1, and the results were basically the same. Due to space limitations, they will not be listed one by one.

[0073] Example 5

[0074] An HCP-type titanium-based multi-principal component composite material, wherein the composite material comprises, by atomic percentage, 14.5% Al, 20% Zr, 0.5% Nb, 0.5% B, 0.05% Si, and 0.05% C, with the balance being Ti and unavoidable impurities.

[0075] The preparation method of the HCP-type titanium-based multi-principal component composite material in this embodiment is as follows:

[0076] (1) The method includes using sponge titanium, sponge zirconium, titanium-niobium master alloy, AlTiB master alloy, carbon powder and aluminum-silicon alloy as raw materials, mixing the raw materials according to their atomic percentages and carrying out vacuum self-consumption melting, melting at least three times to obtain an ingot; wherein, the melting vacuum degree is <1Pa, the equipment leakage rate is <0.5Pa / min, the melting current is 5.5kA, and the melting voltage is 34V;

[0077] (2) The ingot is hot-processed by extrusion at a temperature of 1100℃ and an extrusion ratio of ≥10 to obtain a bar. The bar is then heat-treated at 850℃ for 1 hour and air-cooled to obtain the HCP type titanium-based multi-principal composite material.

[0078] The matrix grain size of the composite material in this embodiment is 25-100 μm. The composite material in this embodiment was tested in Example 1, and the results were basically the same. Due to space limitations, they will not be listed one by one.

[0079] Comparative Example 1

[0080] The raw materials and preparation method of the HCP-type titanium-based multi-principal component composite material in this comparative example are the same as those in Example 1, except that B is 0.2%.

[0081] Comparative Example 2

[0082] The raw materials and preparation method of the HCP-type titanium-based multi-principal component composite material in this comparative example are the same as those in Example 1, except that B is 2%.

[0083] Comparative Example 3

[0084] The raw materials and preparation method of the HCP-type titanium-based multi-principal component composite material in this comparative example are the same as those in Example 1, except that Nb is 5%.

[0085] Experimental Example 1

[0086] The properties of the composite materials prepared in Examples 1-5 and Comparative Examples 1-3 were tested respectively, and the results are shown in Table 1.

[0087] Table 1

[0088] Example 1 4.89 1325 6 672 Example 2 4.76 1290 7 650 Example 3 4.95 1253 6 702 Example 4 4.85 1276 8 661 Example 5 4.80 1259 10 657 Comparative Example 1 4.89 1306 9 570 Comparative Example 2 4.89 1281 2 672 Comparative Example 3 5.10 1319 8 602

[0089] As can be seen from Table 1, the density of the composite material prepared in this invention is 4.76–4.95 g / cm³. 3 The room temperature strength is 1253-1325 MPa, the plastic elongation is 6-10%, and the strength at 750℃ is 650-702 MPa.

[0090] As can be seen from Comparative Examples 1-3, the composite materials prepared outside the proportions specified by this invention exhibit poor performance. Specifically, in Comparative Example 1, the addition of B at 0.2% was insufficient to significantly enhance the high-temperature performance of the composite material, with a strength of only 570 MPa at 750°C.

[0091] In Comparative Example 2, the addition of 2% B resulted in an excess of boride, causing the room temperature elongation of the material to be only 2%.

[0092] In Comparative Example 3, the Zr+Nb content was 29.5%. The addition of excess β-stabilizing elements resulted in a matrix composed of both HCP and BCC phases. The phase diagram calculation results are as follows: Figure 3 As shown, the presence of the BCC phase weakens the material's high-temperature strength, which is only 602 MPa. Furthermore, the phase transition point of this material is around 780℃, and it exhibits structural instability at 750℃. In addition, the excessive addition of Zr and Nb increases the material's density to 5.1 g / cm³. 3 .

[0093] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An HCP-type titanium-based multi-principal component composite material, characterized in that, The composite material, by atomic percentage, comprises Al 14.5~17%, Zr 1.5~24.5%, Nb 0.5~17.5%, B 0.5~1.5%, 0≤C+Si≤0.2%, with the balance being Ti and unavoidable impurities; wherein, 19%≤Zr+Nb≤25%; The matrix structure of the composite material is an HCP-type crystal structure; The density of the composite material is <5.0 g / cm³. 3 Room temperature strength ≥1250MPa, plastic elongation ≥6%, high temperature strength at 750℃ ≥650MPa; The preparation method of the composite material includes using sponge titanium, sponge zirconium, titanium-niobium master alloy, AlTiB master alloy, carbon powder and aluminum-silicon alloy as raw materials, mixing the raw materials according to the atomic percentage, and then performing melting and thermomechanical treatment to obtain the HCP type titanium-based multi-principal component composite material.

2. The HCP-type titanium-based multi-principal component composite material according to claim 1, characterized in that, The matrix grain size of the composite material is 25~100μm.

3. The HCP-type titanium-based multi-principal component composite material according to claim 1 or 2, characterized in that, The reinforcement of the composite material is in-situ self-generated titanium boride.

4. The HCP-type titanium-based multi-principal component composite material according to claim 3, characterized in that, The reinforcement is in the form of short rods and is diffusely distributed in the matrix of the composite material.

5. A method for preparing the composite material according to any one of claims 1-4, characterized in that, The method involves using sponge titanium, sponge zirconium, titanium-niobium master alloy, AlTiB master alloy, carbon powder, and aluminum-silicon alloy as raw materials. The raw materials are mixed and smelted according to their atomic percentages, and then subjected to thermomechanical treatment to obtain the HCP-type titanium-based multi-principal component composite material.

6. The preparation method according to claim 5, characterized in that, The smelting process employs a vacuum consumable melting method, involving at least three smelting operations.

7. The preparation method according to claim 6, characterized in that, The melting vacuum degree is <1Pa, the equipment leakage rate is <0.5Pa / min, the melting current is 3~6kA, and the melting voltage is 25~35V.

8. The preparation method according to claim 5, characterized in that, The thermomechanical treatment includes at least one of forging, extrusion, or hot rolling.

9. The preparation method according to claim 8, characterized in that, The thermomechanical treatment is carried out by extrusion to obtain a bar, and the bar is then subjected to heat treatment.

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