A method for adjusting the modulus temperature coefficient of a titanium alloy material

Abstract

The application belongs to the field of material performance adjustment, and particularly relates to a method for adjusting modulus temperature coefficient of titanium alloy material. Step 1: preparing high-purity titanium alloy powder; step 2: formulating a printing strategy and establishing a process model; step 3: first layer adjustment method: designing process parameters, and confirming energy input value P according to the relationship between energy input value P and modulus temperature coefficient X; step 4: second layer adjustment method: determining printing angle alpha according to the relationship between printing angle alpha and modulus temperature coefficient X; step 5: printing and preparing titanium alloy; step 6: third layer adjustment method: performing vacuum aging treatment on the titanium alloy obtained in step 5, and adjusting aging temperature T and aging time Y according to the relationship among aging temperature T, aging time Y and modulus temperature coefficient X; and step 7: ending heat preservation and vacuum cooling to room temperature. The modulus temperature coefficient of the titanium alloy is successfully adjusted by combining electron beam additive manufacturing technology with aging treatment.

Description

Technical fields:

[0001] This invention belongs to the field of material property adjustment, specifically relating to a method for adjusting the temperature coefficient of modulus of titanium alloy materials. Background technology:

[0002] Due to the existence of atomic harmonic vibrations, the elastic modulus of conventional materials typically decreases with increasing temperature, a phenomenon that is extremely detrimental to the accuracy of precision instruments. The traditional method for controlling the temperature coefficient of modulus is to adjust the alloy composition; for example, adjusting the nickel content in an iron-nickel alloy can adjust the temperature coefficient of modulus from positive to zero and then to negative. Swiss physicist Dr. C.E. Guillaume was awarded the Nobel Prize for discovering this phenomenon. However, controlling the temperature coefficient by adjusting alloying elements is quite complex. This means that when alloys with different temperature coefficients of modulus are needed, the alloy must be smelted from scratch, and then undergo a series of subsequent processes such as casting, forging, and rolling to bring the alloy to the required specifications. This process is complex and costly.

[0003] In recent years, scientists have discovered that the temperature coefficient of modulus in titanium-niobium alloys can be adjusted by controlling the volume fraction of the orthorth phase. The temperature coefficient of modulus decreases with increasing orthorth phase content. Based on existing theory, how to combine this with processing techniques to prepare titanium alloys with controllable and stable temperature coefficients of different moduli has become an urgent problem to be solved. Summary of the Invention:

[0004] In view of this, and to address the shortcomings of the aforementioned technologies, the present invention provides a method for adjusting the modulus temperature coefficient of titanium alloy materials. This method utilizes electron beam additive manufacturing technology and, by adjusting the printing process parameters and subsequent aging treatment, can prepare materials with a predetermined modulus temperature coefficient.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for adjusting the temperature coefficient of modulus of titanium alloy materials, the method comprising the following steps:

[0007] Step 1: Prepare high-purity titanium alloy powder;

[0008] Step 2: Develop a printing strategy and establish a process model, including:

[0009] Establish the temperature coefficient of modulus X×10 -4 The mapping relationship with energy input value P, printing angle α, aging temperature T, and aging time Y is X = f(P, α, T, Y);

[0010] Step 3: First-level adjustment method: Design process parameters, and confirm the energy input value P based on the relationship between the energy input value P and the modulus temperature coefficient X;

[0011] Step 4: Second layer adjustment method: Determine the printing angle α based on the relationship between the printing angle α and the modulus temperature coefficient X;

[0012] Step 5: Perform printing to prepare the titanium alloy;

[0013] Step 6: Third-layer adjustment method: Perform vacuum aging treatment on the titanium alloy obtained in Step 5. Adjust the aging temperature T and aging time Y according to the relationship between aging temperature T, aging time Y, and modulus temperature coefficient X, wherein the vacuum pressure is less than 1×10⁻⁶. -1 Pa;

[0014] Step 7: After the heat preservation is completed, vacuum cool to room temperature at a rate of 5-20℃ / min.

[0015] In step 2, the printing angle α refers to the angle between the alloy growth direction and the printing direction, and the energy input value P refers to:

[0016]

[0017] U is the electron gun voltage (V); I is the electron beam current (mA); H is the powder layer thickness (μm); V is the scanning speed (m / s); L is the scanning spacing (μm).

[0018] In step 3, the first adjustment method refers to setting the temperature coefficient for preparing the target modulus to X×10. -4 For alloys with X>10, the energy input value P is between 28 and 32 J / mm. 3 Alternatively, the temperature coefficient for preparing the target modulus can be set to X×10. -4 For alloys with (1≤X≤10), the energy input value P is between 32 and 35 J / mm². 3 Alternatively, the temperature coefficient for preparing the target modulus can be set to X×10. -4 For alloys with (X < 1), the energy input value P is between 35 and 37 J / mm². 3 .

[0019] In step 4, the second adjustment method refers to setting the temperature coefficient for preparing the target modulus to X×10. -4 For alloys with X>10, the alloy printing angle is between 45° and 90°; or, the target modulus temperature coefficient is set to X×10. -4 For alloys with a modulus of (1≤X≤10), the alloy printing angle is between 10° and 45°; or, the target modulus temperature coefficient is set to X×10. -4 For alloys with (X < 1), the alloy printing angle is 0 to 10°.

[0020] In step 6, the third adjustment method refers to setting the temperature coefficient for preparing the target modulus to X×10. -4 For alloys with (X>10), the aging temperature T for aging treatment is 200–250℃, the heating rate is 5–10℃ / min, and the aging time Y is 2–4 hours; the aging temperature T and aging time Y for subsequent aging treatments are 0; or, the temperature coefficient for preparing the target modulus is set to X×10. -4 For alloys with a modulus of (1≤X≤10), the aging treatment process consists of two steps: Step 1 aging treatment, with an aging temperature T of 200–250℃, a heating rate of 5–10℃ / min, and an aging time Y of 2–4 hours; Step 2 aging treatment, with an aging temperature T of 400–500℃, a heating rate of 5–10℃ / min, and an aging time Y of 2–6 hours; or, setting the target modulus temperature coefficient as X×10. -4 For alloys with (X < 1), the aging treatment process consists of two steps: the first step is aging treatment with an aging temperature of 200–250℃, a heating rate of 5–10℃ / min, and an aging time of 2–4 hours; the second step is aging treatment with an aging temperature of 500–550℃, a heating rate of 5–10℃ / min, and an aging time of 6–12 hours.

[0021] In step 6, before vacuum aging treatment, the titanium alloy obtained in step 5 is subjected to surface powder treatment and ultrasonic cleaning.

[0022] The modulus temperature coefficient is calculated as follows:

[0023]

[0024] In the formula, Z is the temperature coefficient of modulus, and ΔE T E is the elastic modulus (GPa). 25℃ ΔT represents the elastic modulus (GPa) at 25℃; ΔT represents the temperature range (℃).

[0025] The design concept of this invention is:

[0026] Controlling the volume fraction of the orthorth phase in titanium-niobium alloys can adjust the temperature modulus. Research has shown that different process parameters and printing angles in electron beam additive manufacturing of titanium-niobium alloys have a certain influence on the final volume fraction of the orthorth phase. However, this single adjustment method is insufficient to regulate the temperature modulus over a wide range. Therefore, combining aging treatment with other methods further adjusts the volume fraction of the orthorth phase, achieving the goal of regulating the temperature modulus over a broader range.

[0027] The advantages and beneficial effects of this invention are:

[0028] This invention provides a method for adjusting the temperature coefficient of modulus of titanium alloys. Compared with methods for adjusting the modulus of iron-nickel alloys by modifying the composition, this method can adjust the temperature coefficient of modulus of titanium alloys using a simple process. Furthermore, through the combined effect of three adjustment methods, the final temperature coefficient of modulus of the alloy can be predicted. This method has broad application prospects in the fields of biomedical materials, aerospace, and the fabrication of precision instruments. Attached image description:

[0029] Figure 1 Example 1: Modulus coefficient versus temperature change curve.

[0030] Figure 2 Example 2: Modulus coefficient versus temperature change curve.

[0031] Figure 3 Example 3: Modulus coefficient versus temperature change curve. Detailed implementation method:

[0032] In its specific implementation, this invention proposes a method for adjusting the modulus temperature coefficient of titanium alloy materials. Step 1: Prepare high-purity titanium alloy powder; Step 2: Develop a printing strategy and establish a process model, including: establishing a modulus temperature coefficient X×10. -4 The mapping relationship between energy input value P, printing angle α, aging temperature T, and aging time Y is X = f(P, α, T, Y); Step 3: First-level adjustment method: Design process parameters and confirm the energy input value P based on the relationship between energy input value P and modulus temperature coefficient X; Step 4: Second-level adjustment method: Determine the printing angle α based on the relationship between printing angle α and modulus temperature coefficient X; Step 5: Perform printing to prepare titanium alloy; Step 6: Third-level adjustment method: Perform vacuum aging treatment on the titanium alloy obtained in Step 5, and adjust the aging temperature T and aging time Y based on the relationship between aging temperature T, aging time Y, and modulus temperature coefficient X, performing a two-step aging treatment; Step 7: After heat preservation, vacuum cool to room temperature.

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments. The following embodiments are merely some examples of the present invention and are not intended to limit the scope of the present invention.

[0034] Example 1:

[0035] In this embodiment, a method for adjusting the temperature coefficient of modulus of titanium alloy materials includes the following steps:

[0036] Step 1: Prepare high-purity titanium alloy powder; the raw material is Ti-24Nb (wt.%) alloy.

[0037] Step 2: Develop a printing strategy, establish a process model, and preset the modulus temperature coefficient to X×10. -4 (X=20) titanium alloy.

[0038] Step 3: First-level adjustment method: Design process parameters, and confirm the energy input value P based on the relationship between the energy input value P and the modulus temperature coefficient X;

[0039] The target modulus temperature coefficient is set at 20 × 10⁻⁶. -4 An energy input density of 28 J / mm² was selected. 3 The process parameters.

[0040] Step 4: Second layer adjustment method: Determine the printing angle α based on the relationship between the printing angle α and the modulus temperature coefficient X; set the target modulus temperature coefficient to 20×10. -4 The alloy printing angle is 90°.

[0041] Step 5: Print to prepare titanium alloy, and perform surface powder treatment and ultrasonic cleaning on the surface of the obtained titanium alloy. Surface powder treatment refers to removing the powder adhering to the surface of the prepared alloy.

[0042] Step 6: Third-layer adjustment method: Perform vacuum aging treatment on the titanium alloy obtained in Step 5. Based on the relationship between aging temperature T, aging time Y, and modulus temperature coefficient X, adjust the aging temperature T and aging time Y. The vacuum pressure is 5 × 10⁻⁶. - 2 Pa; The target modulus temperature coefficient is set to 20 × 10⁻⁶. -4 The first step of aging treatment: the aging temperature T is 220℃, the heating rate is 8℃ / min, and the aging time Y is 2 hours; the second step of aging treatment: the aging temperature T and the aging time Y are 0.

[0043] Step 7: After heat preservation, vacuum cool to room temperature at a rate of 5℃ / min;

[0044] The modulus temperature coefficient of the alloy was finally obtained by measuring it using a dynamic thermomechanical analyzer (DMA) in the range of 25℃ to 300℃, and the modulus temperature coefficient was found to be 21 × 10⁻⁶. -4 The titanium alloy is basically consistent with the preset value, and the modulus-temperature curve is as follows: Figure 1 As shown.

[0045] Example 2:

[0046] In this embodiment, a method for adjusting the temperature coefficient of modulus of titanium alloy materials includes the following steps:

[0047] Step 1: Prepare high-purity titanium alloy powder; the raw material is Ti-24Nb (wt.%) alloy.

[0048] Step 2: Develop a printing strategy, establish a process model, and preset the modulus temperature coefficient to X×10. -4 (X=3) titanium alloy.

[0049] Step 3: First-level adjustment method: Design process parameters, and confirm the energy input value P based on the relationship between the energy input value P and the modulus temperature coefficient X;

[0050] The target temperature coefficient of modulus is set at 3.0 × 10⁻⁶. -4 An energy input density of 34 J / mm was selected. 3 The process parameters.

[0051] Step 4: Second layer adjustment method: Determine the printing angle α based on the relationship between the printing angle α and the modulus temperature coefficient X; set the target modulus temperature coefficient to 3.0 × 10⁻⁶. -4 The alloy printing angle is 10°.

[0052] Step 5: Print to prepare titanium alloy, and perform surface powder treatment and ultrasonic cleaning on the surface of the obtained titanium alloy. Surface powder treatment refers to removing the powder adhering to the surface of the prepared alloy.

[0053] Step 6: Third-layer adjustment method: Perform vacuum aging treatment on the titanium alloy obtained in Step 5. Adjust the aging temperature T and aging time Y according to the relationship between aging temperature T, aging time Y, and modulus temperature coefficient X. The vacuum pressure is 3 × 10⁻⁶. - 2 Pa; The target modulus temperature coefficient is set at 3.0 × 10⁻⁶. -4 The first aging treatment: aging temperature T is 240℃, heating rate is 10℃ / min, and aging time Y is 3 hours. The second aging treatment: aging temperature is 420℃, heating rate is 10℃ / min, and aging time is 2.5 hours.

[0054] Step 7: After heat preservation, vacuum cool to room temperature at a rate of 10℃ / min;

[0055] The modulus temperature coefficient of the alloy was finally obtained by measuring it using a dynamic thermomechanical analyzer (DMA) from 25℃ to 300℃, and the modulus temperature coefficient was found to be 2.8 × 10⁻⁶. -4 The modulus-temperature curve of the titanium alloy is shown in the data as follows: Figure 2 As shown.

[0056] Example 3:

[0057] In this embodiment, a method for adjusting the temperature coefficient of modulus of titanium alloy materials includes the following steps:

[0058] Step 1: Prepare high-purity titanium alloy powder; the raw material is Ti-24Nb (wt.%) alloy.

[0059] Step 2: Develop a printing strategy, establish a process model, and preset the modulus temperature coefficient to X×10. -4 Titanium alloy with (X = -1).

[0060] Step 3: First-level adjustment method: Design process parameters, and confirm the energy input value P based on the relationship between the energy input value P and the modulus temperature coefficient X;

[0061] The target modulus temperature coefficient is set to -1×10. -4 An energy input density of 35 J / mm² was selected. 3 The process parameters.

[0062] Step 4: Second layer adjustment method: Determine the printing angle α based on the relationship between the printing angle α and the modulus temperature coefficient X; set the target modulus temperature coefficient to -1×10. -4 The alloy printing angle is 0°.

[0063] Step 5: Print to prepare titanium alloy, and perform surface powder treatment and ultrasonic cleaning on the surface of the obtained titanium alloy. Surface powder treatment refers to removing the powder adhering to the surface of the prepared alloy.

[0064] Step 6: Third-layer adjustment method: Perform vacuum aging treatment on the titanium alloy obtained in Step 5. Based on the relationship between aging temperature T, aging time Y, and modulus temperature coefficient X, adjust the aging temperature T and aging time Y. The vacuum pressure is 4 × 10⁻⁶. - 2 Pa; The target modulus temperature coefficient is set to -1 × 10⁻⁶. -4 The first aging treatment: the aging temperature T is 250℃, the heating rate is 10℃ / min, and the aging time Y is 4 hours; the second aging treatment: the aging temperature T is 550℃, the heating rate is 10℃ / min, and the aging time Y is 6 hours.

[0065] Step 7: After heat preservation, vacuum cool to room temperature at a rate of 20℃ / min;

[0066] The modulus temperature coefficient of the alloy was finally obtained by measuring it using a dynamic thermomechanical analyzer (DMA) from 25℃ to 300℃, and the obtained modulus temperature coefficient was -1.5×10⁻⁶. -4 The modulus-temperature curve of the titanium alloy is shown in the data as follows: Figure 3 As shown.

[0067] The results show that the present invention successfully controls the modulus temperature coefficient of titanium alloys by combining electron beam additive manufacturing technology with aging treatment.

Claims

1. A method for adjusting the temperature coefficient of modulus of titanium alloy materials, characterized in that, The adjustment method consists of the following steps: Step 1: Prepare high-purity titanium alloy powder; Step 2: Develop a printing strategy and establish a process model, including: Establish the temperature coefficient of modulus X×10 -4 The mapping relationship between / ℃ and energy input value P, printing angle α, aging temperature T and aging time Y is expressed as X=f(P, α, T, Y). Step 3: First-level adjustment method: Design process parameters, and confirm the energy input value P based on the relationship between the energy input value P and the modulus temperature coefficient X; Step 4: Second layer adjustment method: Determine the printing angle α based on the relationship between the printing angle α and the modulus temperature coefficient X; Step 5: Perform printing to prepare the titanium alloy; Step 6: Third-layer adjustment method: Perform vacuum aging treatment on the titanium alloy obtained in Step 5. Adjust the aging temperature T and aging time Y according to the relationship between aging temperature T, aging time Y, and modulus temperature coefficient X, wherein the vacuum pressure is less than 1×10⁻⁶. -1 Pa; Step 7: After heat preservation, vacuum cool to room temperature at a rate of 5~20℃ / min; In step 2, the printing angle α refers to the angle between the alloy growth direction and the printing direction, and the energy input value P refers to: U is the electron gun voltage (V); I is the electron beam current (mA); H is the powder layer thickness (μm); V is the scanning speed (m / s); and L is the scanning spacing (μm).

2. The method for adjusting the temperature coefficient of modulus of titanium alloy materials according to claim 1, characterized in that, In step 3, the first adjustment method refers to setting the temperature coefficient for preparing the target modulus to X×10. -4 For alloys with a temperature coefficient of X > 10 at / ℃, the energy input value P is between 28 and 32 J / mm³; or, the target modulus temperature coefficient is set to X × 10. -4 For alloys with a temperature range of ℃ and 1≤X≤10, the energy input value P is between 32~35J / mm³; or, the target modulus temperature coefficient is set to X×10. -4 For alloys with a temperature of ℃ and X < 1, the energy input value P is between 35 and 37 J / mm³.

3. The method for adjusting the temperature coefficient of modulus of titanium alloy materials according to claim 1, characterized in that, In step 4, the second adjustment method refers to setting the temperature coefficient for preparing the target modulus to X×10. -4 For alloys with a temperature coefficient of / ℃ and X>10, the alloy printing angle is between 45° and 90°; or, the target modulus temperature coefficient is set to X×10. -4 For alloys with a temperature coefficient of ℃ and 1≤X≤10, the alloy printing angle is between 10 and 45°; or, the target modulus temperature coefficient is set to X×10. -4 For alloys with a temperature of / ℃ and X < 1, the alloy printing angle is 0~10°.

4. The method for adjusting the temperature coefficient of modulus of titanium alloy materials according to claim 1, characterized in that, In step 6, the third adjustment method refers to setting the temperature coefficient for preparing the target modulus to X×10. -4 For alloys where X > 10 and the aging temperature T is 200-250℃, the heating rate is 5-10℃ / min, and the aging time Y is 2-4 hours; the aging temperature T and aging time Y for subsequent aging treatments are 0; or, the temperature coefficient of the target modulus is set to X × 10. -4 For alloys with a temperature range of 1 / ℃ and 1≤X≤10, the aging treatment consists of two steps: Step 1 aging treatment, aging temperature T: 200~250℃, heating rate 5~10℃ / min, aging time Y: 2~4 hours; Step 2 aging treatment, aging temperature T: 400~500℃, heating rate 5~10℃ / min, aging time Y: 2~6 hours; or, setting the target modulus temperature coefficient as X×10. -4 For alloys with a temperature of / ℃ and X < 1, the aging treatment process consists of two steps: the first step is aging treatment with an aging temperature T of 200~250℃, a heating rate of 5~10℃ / min, and an aging time Y of 2~4 hours; the second step is aging treatment with an aging temperature T of 500~550℃, a heating rate of 5~10℃ / min, and an aging time of 6~12 hours.

5. The method for adjusting the temperature coefficient of modulus of titanium alloy materials according to claim 1, characterized in that, In step 6, before vacuum aging treatment, the titanium alloy obtained in step 5 is subjected to surface powder removal treatment and ultrasonic cleaning.

6. The method for adjusting the temperature coefficient of modulus of titanium alloy materials according to claim 1, characterized in that, The modulus temperature coefficient is calculated as follows: In the formula, Z is the temperature coefficient of modulus, / ℃; ΔE T E represents the change in elastic modulus, expressed in GPa. 25℃ ΔT is the elastic modulus at 25℃, in GPa; ΔT is the change in temperature, in ℃.

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