Preparation process of additive manufacturing 600 DEG C high-temperature titanium alloy

Abstract

The application relates to the technical field of metal additive manufacturing, in particular to a preparation process of additive manufacturing of 600 DEG C high-temperature titanium alloy, mainly adopting titanium alloy powder chemical components: C: 0.01%-0.09%, Si: 0.20%-0.55%, Mo: 0.2%-1.5%, Al: 5.0%-6.3%, Nb: 0.2%-1.0%, Zr: 2.5%-7.0%, Ta: 0.2%-3.0%, Sn: 3.0%-5.0%, H: <=0.006%, O: <=0.150%, N: <=0.050%, and the balance is Ti; the particle size of the powder is 15-53 mu m, the loose bulk density is >=1.9 g / cm 3 , the tap density is >=2.3 g / cm 3 , the sphericity is >=0.9, the fluidity is <=38 s / 50 g; the 600 DEG C high-temperature titanium alloy is obtained through heat treatment after printing by a selective laser melting forming process, has high compactness, good high-temperature strength above 600 DEG C, and excellent room-temperature performance.

Description

Technical Field

[0001] This invention relates to the field of metal additive manufacturing technology, and in particular to a preparation process for additive manufacturing of 600°C high-temperature titanium alloys. Background Technology

[0002] Titanium alloys have the following advantages:

[0003] (1) High specific strength. Titanium alloys have a very low density, only about 57% of that of steel and about 55% of that of high-temperature alloys, while their strength is very high, with a tensile strength of 686MPa-1176MPa, which is comparable to that of general high-strength structural steel and high-temperature alloys. Therefore, titanium alloys have a very high specific strength.

[0004] (2) High hardness. The hardness of titanium alloys in the annealed state is generally 32HRC-38HRC.

[0005] (3) Low elastic modulus and low thermal conductivity. The elastic modulus of titanium alloy in the annealed state is 1.078 × 10⁻⁶. 5 MPa -1.176×10 5 It has a strength of MPa, approximately half that of steel, and a thermal conductivity approximately 1 / 14 that of aluminum, 1 / 5 that of iron, or 1 / 4 that of nickel.

[0006] (4) Excellent high and low temperature performance. Titanium has a melting point of 1668℃, which is more than 1000℃ higher than that of aluminum. Therefore, the thermal strength of titanium alloys is much higher than that of aluminum alloys. The maximum service temperature of the alloy is mainly limited by oxidation. The service temperature of titanium alloys can reach above 600℃, while the maximum service temperature of aluminum alloys is generally only 200℃. Titanium alloys can maintain good mechanical properties at high temperatures, and they have a wide range of selectable operating temperatures. The heat resistance of titanium alloys is much higher than that of aluminum alloys. The strength of titanium alloys increases at low temperatures compared to room temperature, and they have good low-temperature toughness.

[0007] (5) Strong corrosion resistance. At 550℃, titanium will quickly form a dense oxide film in the air, and the oxide film can regenerate immediately after it is damaged. Therefore, titanium alloys have excellent corrosion resistance in oxidizing and strong alkaline media.

[0008] However, titanium alloys have poor wear resistance and machinability, making them difficult to machine and requiring complex manufacturing processes. Furthermore, they easily absorb impurities such as H, O, N, and C during hot working.

[0009] Furthermore, conventional titanium alloys, such as TC4 titanium alloy, typically operate at temperatures around 300℃-350℃ for extended periods, where their performance degrades significantly. However, critical aerospace components, especially integral bladed disks for aero engines, usually require operating temperatures above 600℃. Therefore, developing a titanium alloy with good high-temperature strength above 600℃ is of great significance.

[0010] Metal additive manufacturing (3D printing) is a crucial technology playing a vital role in integrated and lightweight product design. Titanium alloys are widely used in the aerospace industry due to their superior properties. However, titanium alloys suffer from poor machinability, are difficult to thermoform, and have high manufacturing costs. Selective laser melting (SLM) technology can overcome the shortcomings of traditional forming methods for manufacturing titanium alloy parts, significantly improving material utilization and reducing costs, thus showing broad application prospects. Summary of the Invention

[0011] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a preparation process for additive manufacturing of 600°C high-temperature titanium alloys, which can produce titanium alloys with good high-temperature strength above 600°C.

[0012] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0013] A process for additive manufacturing of a 600℃ high-temperature titanium alloy includes the following steps: Step 1: Using titanium alloy powder with the following chemical composition: C: 0.01%-0.09%, Si: 0.20%-0.55%, Mo: 0.2%-1.5%, Al: 5.0%-6.3%, Nb: 0.2%-1.0%, Zr: 2.5%-7.0%, Ta: 0.2%-3.0%, Sn: 3.0%-5.0%, H: ≤0.006%, O: ≤0.150%, N: ≤0.050%, with the balance being Ti; the titanium alloy powder meets the following requirements: powder particle size: 15μm-53μm, loose packing density: ≥1.9g / cm³. 3 Tap density: ≥2.3 g / cm³ 3 Powder sphericity: ≥0.9, powder flowability: ≤38s / 50g, non-metallic inclusions in the powder are no more than 5 particles / 100g, hollow powder in the powder is no more than 0.3%, the powder appearance is silver-gray, and there are no foreign objects or agglomeration; Step 2: Using titanium alloy powder, the molded parts are printed by selective laser melting forming process; Step 3: The molded parts are heat treated to obtain 600℃ high temperature titanium alloy.

[0014] Preferably, in step 1, the particle size distribution of the titanium alloy powder satisfies the following conditions: the particle size D10 corresponding to 10% of the cumulative distribution curve under volume is ≥22μm, the particle size D50 corresponding to 50% of the cumulative distribution curve under volume is ≤33.4μm, and the particle size D90 corresponding to 90% of the cumulative distribution curve under volume is ≤51μm.

[0015] Preferably, in step 2, the printing process parameters for selective laser melting are: laser power: 150W-250W, scanning speed: 800mm / s-1200mm / s, scanning spacing: 0.08mm-0.12mm, and printing layer thickness: 30μm.

[0016] Preferably, in step 2, the laser power is 150W-170W, the scanning speed is 1100mm / s-1200mm / s, and the scanning interval is 0.10mm.

[0017] Preferably, in step 3, the heat treatment process is as follows: the temperature is raised to 580℃-630℃ at room temperature for 60 minutes, and then held for 2h-2.5h; then the temperature is raised to 800℃-900℃ and held for 2h-3h; then the temperature is cooled to room temperature.

[0018] Preferably, in step 3, the heat treatment process is as follows: the temperature is raised to 600℃-610℃ in 60 minutes at room temperature, and then held for 2h-2.5h; then the temperature is raised to 860℃-870℃ and held for 2h-3h; then the temperature is cooled to room temperature.

[0019] Preferably, the high-temperature mechanical properties of the 600℃ high-temperature titanium alloy at 600℃ are: tensile strength ≥800MPa, yield strength ≥570MPa, and elongation ≥7%.

[0020] Compared with the prior art, the present invention has significant progress:

[0021] The additive manufacturing process for 600℃ high-temperature titanium alloys of this invention involves developing a titanium alloy powder suitable for temperatures above 600℃, utilizing selective laser melting (SLM) to prepare high-density 600℃ high-temperature titanium alloy molded parts by adjusting and optimizing printing process parameters. Then, through appropriate heat treatment, a 600℃ high-temperature titanium alloy material with high density, good strength above 600℃, and excellent room-temperature performance is obtained, thus meeting the application requirements of titanium alloys under high-temperature service conditions. This additive manufacturing process for 600℃ high-temperature titanium alloys has a short production cycle, can directly mold complex-shaped parts, and the molded parts have high precision, high density, and excellent comprehensive mechanical properties under both room-temperature and high-temperature conditions. Attached Figure Description

[0022] Figure 1 These are micrographs of a 600℃ high-temperature titanium alloy obtained using the additive manufacturing process for a 600℃ high-temperature titanium alloy according to an embodiment of the present invention. Detailed Implementation

[0023] The following is in conjunction with the appendix Figure 1 The specific embodiments of the present invention will be described in further detail below. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0024] This invention provides a process for additive manufacturing of a 600℃ high-temperature titanium alloy. The process includes the following steps.

[0025] Step 1: Use titanium alloy powder with the following chemical composition (wt / %) as raw material:

[0026] C: 0.01%-0.09%, Si: 0.20%-0.55%, Mo: 0.2%-1.5%, Al: 5.0%-6.3%, Nb: 0.2%-1.0%, Zr: 2.5%-7.0%, Ta: 0.2%-3.0%, Sn: 3.0%-5.0%, H: ≤0.006%, O: ≤0.150%, N: ≤0.050%, balance Ti.

[0027] The chemical composition of the titanium alloy powder used meets the requirements of the "Technical Requirements for the Development of Ti-60 Alloy Powder for Additive Manufacturing of High-Temperature Heat Exchange Units". In a specific embodiment, the chemical composition of the actually manufactured titanium alloy powder is shown in Table 1 below.

[0028] Table 1 Chemical composition of titanium alloy powder

[0029] mass percentage Wt / % Bal. 5.66 1.02 4.02 0.015 4.89 Element Mo Nb Si C O N mass percentage Wt / % 0.89 0.66 0.24 0.040 0.11 0.0057

[0030] The titanium alloy powder used meets the following conditions:

[0031] Powder particle size: 15μm-53μm, meaning the main particle size distribution is 15μm-53μm. Preferably, the particle size distribution of the titanium alloy powder meets the following requirements: D10 ≥ 22μm for 10% of the cumulative distribution curve, D50 ≤ 33.4μm for 50% of the cumulative distribution curve, and D90 ≤ 51μm for 90% of the cumulative distribution curve. Powder particle size and particle size distribution determination should be performed according to the methods specified in GB / T1480 or GB / T19077, and the acceptance criterion is meeting the above conditions.

[0032] Loose bulk density: ≥1.9g / cm³ 3 Tap density: ≥2.3 g / cm³ 3 Powder density determination shall be carried out in accordance with GB / T1479.1 and GB / T5162. One sample shall be tested for each batch of powder, and each sample shall weigh no less than 600g. The acceptance standard is that the loose density is at least 1.9g / cm³. 3 The tap density is at least 2.3 g / cm³. 3 .

[0033] Powder sphericity: ≥0.9. The determination of powder sphericity shall be carried out in accordance with GB / T39251 Dynamic Particle Image Analysis Method. One sample shall be tested for each batch of powder, and each sample shall be no less than 50g. The acceptance standard is that the powder sphericity is not less than 0.9.

[0034] Powder flowability: ≤38s / 50g. The powder flowability test shall be conducted in accordance with GB / T1482. One sample shall be tested for each batch of powder, and each sample shall be no less than 200g. The acceptance standard is that the powder flow time shall not exceed 38s / 50g.

[0035] The non-metallic inclusions in the powder shall not exceed 5 particles / 100g. The determination of non-metallic inclusions in the powder shall be carried out by industrial CT method according to the standard of GB / T39251. One sample shall be tested for each batch of powder, and each sample shall not be less than 100g. The acceptance standard is that the non-metallic inclusions in the powder shall not exceed 5 particles / 100g.

[0036] The hollow powder content shall not exceed 0.3%. The determination of hollow powder content shall be performed using an industrial CT method, in accordance with the standard specified in GB / T39251. One sample shall be tested per batch of powder, with each sample containing no less than 100g. The acceptance criterion is that the hollow powder content shall not exceed 0.3%.

[0037] Powder appearance quality: The powder should be silver-gray in appearance and free from foreign matter and clumping. The appearance quality of the powder is inspected visually, and a 5x-10x magnifying glass may be used if necessary. Each batch of powder is packaged in one 200g portion for appearance quality inspection. The powder should be silver-gray in appearance and free from foreign matter and clumping.

[0038] Step 2: Using the titanium alloy powder used in Step 1, print the molded part through selective laser melting process.

[0039] Preferably, the printing process parameters for selective laser melting forming in step 2 are as follows:

[0040] Laser power: 150W-250W, with 150W-170W being the best;

[0041] Scanning speed: 800mm / s-1200mm / s, with 1100mm / s-1200mm / s being the optimal speed;

[0042] Scanning interval: 0.08mm-0.12mm, with approximately 0.10mm being the optimal value;

[0043] Printing layer thickness: 30μm.

[0044] Preferably, the scanning strategy is strip scanning with layer-by-layer rotation, with a rotation angle of 67°.

[0045] After metallographic polishing of the shaped part obtained in step 2, it was observed under a microscope to obtain a micrograph of the 600℃ high-temperature titanium alloy obtained by the additive manufacturing process of this embodiment. Figure 1 As shown, the defect rate of the 600℃ high-temperature titanium alloy molded parts obtained using the optimal printing process parameters in step 2 is as low as 0.007%, exhibiting high density.

[0046] Step 3: Heat treat the molded part printed in Step 2 to obtain a 600℃ high-temperature titanium alloy.

[0047] Preferably, the heat treatment process in step 3 is as follows: heating to 580℃-630℃ from room temperature for 60 minutes, then holding at that temperature for 2h-2.5h; then heating to 800℃-900℃, then holding at that temperature for 2h-3h; and then air cooling to room temperature.

[0048] In a preferred embodiment, the heat treatment process in step 3 is as follows: the temperature is raised to 600℃-610℃ in 60 minutes at room temperature, and then held for 2h-2.5h; then the temperature is raised to 860℃-870℃ and held for 2h-3h; then the temperature is cooled to room temperature.

[0049] More preferably, the heat treatment process in step 3 is as follows: heat the temperature to 600°C in 60 minutes at room temperature, and then hold it for 2 hours; then heat the temperature to 850°C and hold it for 2 hours; then air cool it to room temperature.

[0050] A high-temperature tensile test was conducted on the titanium alloy after heat treatment in step 3 at 600℃. The test results of the high-temperature tensile test (600℃) are shown in Table 2 below.

[0051] Table 2 Results of High Temperature Tensile Test (600℃)

[0052]

[0053] The 600℃ high-temperature titanium alloy obtained by the additive manufacturing process of this embodiment has the following high-temperature mechanical properties at 600℃: tensile strength ≥800MPa, yield strength ≥570MPa, elongation ≥7%, exhibiting excellent strength under high-temperature service conditions and superior comprehensive high-temperature mechanical properties.

[0054] In addition, a room temperature tensile test was conducted on the 600℃ high-temperature titanium alloy after heat treatment in step 3. The test results of the room temperature tensile test are shown in Table 3 below.

[0055] Table 3 Results of room temperature tensile tests

[0056]

[0057] It can be seen that the 600℃ high-temperature titanium alloy obtained by the additive manufacturing process of this embodiment also has good strength under room temperature service conditions and excellent comprehensive mechanical properties at room temperature.

[0058] The additive manufacturing process for 600℃ high-temperature titanium alloys in this embodiment involves developing a titanium alloy powder suitable for temperatures above 600℃, utilizing selective laser melting (SLM) to prepare high-density 600℃ high-temperature titanium alloy molded parts by adjusting and optimizing printing process parameters. Then, through appropriate heat treatment, a 600℃ high-temperature titanium alloy material with high density, good strength above 600℃, and excellent room-temperature performance is obtained, thus meeting the application requirements of titanium alloys under high-temperature service conditions. This additive manufacturing process for 600℃ high-temperature titanium alloys has a short production cycle, can directly mold complex-shaped parts, and the molded parts have high precision, high density, and excellent comprehensive mechanical properties under both room-temperature and high-temperature conditions.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A process for additive manufacturing of a 600℃ high-temperature titanium alloy, characterized in that, Includes the following steps: Step 1: Use titanium alloy powder with the following chemical composition: C: 0.01%-0.09%, Si: 0.20%-0.55%, Mo: 0.2%-1.5%, Al: 5.0%-6.3%, Nb: 0.2%-1.0%, Zr: 2.5%-7.0%, Ta: 0.2%-3.0%, Sn: 3.0%-5.0%, H: ≤0.006%, O: ≤0.150%, N: ≤0.050%, balance Ti; The titanium alloy powder satisfies: Powder particle size: 15μm-53μm, loose density: ≥1.9g / cm3, tapped density: ≥2.3g / cm3, powder sphericity: ≥0.9, powder flowability: ≤38s / 50g, non-metallic inclusions in the powder are no more than 5 particles / 100g, hollow powder in the powder is no more than 0.3%, the powder appearance is silver-gray, and there are no foreign objects or agglomeration. Step 2: Using the titanium alloy powder, the part is printed by selective laser melting forming process. The printing process parameters of selective laser melting forming are: laser power: 150W-250W, scanning speed: 800mm / s-1200mm / s, scanning spacing: 0.08mm-0.12mm, and printing layer thickness: 30μm. Step 3: Heat treat the molded part to obtain a 600℃ high-temperature titanium alloy. The heat treatment process is as follows: heat up to 580℃-630℃ at room temperature for 60 minutes, hold for 2h-2.5h; then heat up to 800℃-900℃, hold for 2h-3h; then air cool to room temperature. The high-temperature mechanical properties of the 600℃ high-temperature titanium alloy at 600℃ are: tensile strength ≥800MPa, yield strength ≥570MPa, and elongation ≥7%.

2. The preparation process for additive manufacturing of 600℃ high-temperature titanium alloy according to claim 1, characterized in that, In step 1, the particle size distribution of the titanium alloy powder satisfies the following conditions: the particle size D10 corresponding to 10% of the cumulative distribution curve under volume is ≥22μm, the particle size D50 corresponding to 50% of the cumulative distribution curve under volume is ≤33.4μm, and the particle size D90 corresponding to 90% of the cumulative distribution curve under volume is ≤51μm.

3. The preparation process for additive manufacturing of 600℃ high-temperature titanium alloy according to claim 1, characterized in that, In step 2, the laser power is 150W-170W, the scanning speed is 1100mm / s-1200mm / s, and the scanning interval is 0.10mm.

4. The preparation process for additive manufacturing of 600℃ high-temperature titanium alloy according to claim 1, characterized in that, In step 3, the heat treatment process is as follows: the temperature is raised to 600℃-610℃ in 60 minutes at room temperature, and then held for 2h-2.5h; then the temperature is raised to 860℃-870℃ and held for 2h-3h; then the temperature is cooled to room temperature.

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