High-titanium nickel niobium-based alloy and preparation method thereof

Abstract

The invention discloses a high-titanium nickel niobium-based alloy and a preparation method thereof, the method comprises the following steps: step 1, niobium alloy powder is prepared and subjected to vacuum drying, the atom proportion of Nb powder in the niobium alloy powder is 60%-75%, the atom proportion of Ti powder in the niobium alloy powder is 15%-25%, the atom proportion of Ni powder in the niobium alloy powder is 6%-12.5%, and the balance is refractory metal element powder; 2, the niobium alloy powder is made into a high-titanium-nickel-niobium-based alloy blank through laser additive manufacturing equipment; and 3, the high-titanium-nickel-niobium-based alloy blank is put into a high-temperature furnace with the high vacuum degree, after the air pressure in the furnace reaches 1 * 10 <-3 > Pa to 5 * 10 <-3 > Pa through a mechanical pump and a diffusion pump, the temperature is increased to 1000-1200 DEG C from the room temperature at the temperature increasing rate of 10 DEG C / min, annealing is conducted for 1-10 h, and after furnace cooling is conducted, the high-titanium-nickel-niobium-based alloy is obtained and has the high melting point and the excellent mechanical property.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy materials, and in particular is a high-titanium nickel-niobium based alloy and a preparation method thereof. Background Art

[0002] In the field of aerospace, with the continuous increase in the speed of aircraft, more stringent requirements are placed on the high temperature resistance and mechanical properties of materials in high temperature environments. The melting point of traditional nickel-based single crystal high temperature alloys is 1400-1500℃, which cannot meet the service requirements of higher temperatures; the melting point of niobium exceeds 2000℃, and the material has good cold working properties, but its yield strength is low.

[0003] Therefore, how to provide an alloy with high melting point and high mechanical strength has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a high-titanium nickel-niobium based alloy and a preparation method thereof. The prepared high-titanium nickel-niobium based alloy has a high melting point and excellent mechanical properties.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for preparing a high-titanium nickel-niobium based alloy comprises the following steps:

[0007] Step 1, preparing niobium alloy powder and vacuum drying, wherein the atomic proportion of Nb powder in the niobium alloy powder is 60% to 75%, the atomic proportion of Ti powder in the niobium alloy powder is 15% to 25%, the atomic proportion of Ni powder in the niobium alloy powder is 6% to 12.5%, and the remainder is refractory metal element powder;

[0008] Step 2: Using laser additive manufacturing equipment to make niobium alloy powder into high-titanium nickel-niobium based alloy billets;

[0009] Step 3: Place the high-titanium-nickel-niobium alloy billet into a high-temperature furnace with high vacuum, and use a mechanical pump and a diffusion pump to make the pressure in the furnace reach 1×10 -3 Pa~5×10 -3 Pa, the temperature is raised from room temperature to 1000-1200°C at a heating rate of 10°C / min, annealed for 1-10h, and then cooled in the furnace to obtain a high-titanium nickel-niobium based alloy.

[0010] Furthermore, in step 1, the refractory metal element is tungsten, molybdenum or zirconium.

[0011] Furthermore, in step 1, the atomic ratio of Ti powder to Ni powder is (2-2.5):1.

[0012] Furthermore, in step 1, the particle sizes of Nb powder, Ti powder and Ni powder are all 15-53 um.

[0013] Furthermore, the process of preparing the niobium alloy powder in step 1 is: putting niobium powder, titanium powder, nickel powder and refractory metal element powder into a powder mixer according to proportions, and mixing for 3 to 6 hours.

[0014] Furthermore, the vacuum drying in step 1 is performed using a vacuum drying oven at 100° C. for 2 hours.

[0015] Furthermore, the laser additive manufacturing equipment in step 2 is a selective laser melting SLM equipment, and its working parameters include: laser scanning speed of 300-700 mm / s, powder layer thickness of 0.01-0.03 mm, scanning spacing of 0.03-0.08 mm, and laser power of 150-250 W.

[0016] Furthermore, the laser additive manufacturing equipment of step 2 is a laser powder bed fusion LPBF 3D printer, the internal oxygen content of which is less than 200 ppm, and the argon content is not less than 97%, and the temperature of the printed substrate is 100-300°C.

[0017] A high-titanium nickel-niobium based alloy comprises a matrix and a network precipitated phase, wherein the matrix is ​​uniformly wrapped by the network precipitated phase.

[0018] Furthermore, the matrix is ​​γ-phase niobium, and the network precipitation phase is Ti2Ni.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] On the one hand, the present invention uses niobium with a high melting point as the alloy matrix, and by adjusting the proportions of niobium, titanium and nickel elements, the high-titanium nickel-niobium-based alloy has both high melting point and excellent mechanical properties; on the other hand, by laser melting niobium alloy powder, a small molten pool can be formed, which plays a role in accurately controlling the elemental composition of the alloy, forming a continuous network of Ti2Ni in the alloy, and achieving the purpose of improving the strength of the alloy; on the one hand, by utilizing the annealing process, the thermal stress during the forming of the niobium alloy is reduced, the network Ti2Ni structure is optimized, and the high-titanium nickel-niobium-based alloy is given more excellent tensile properties; in addition, by introducing a small amount of refractory metal elements, the high temperature resistance of the high-titanium nickel-niobium-based alloy can be further improved.

[0021] The present invention designs the atomic ratio of Ti powder and Ni powder to be (2-2.5):1, so that the surface of the γ-phase niobium matrix is ​​coated with a high-strength network precipitation phase Ti2Ni, thereby improving the strength of the niobium matrix through the second phase Ti2Ni, and obtaining a high-titanium-nickel-niobium-based alloy with excellent mechanical properties.

[0022] The present invention controls the oxygen content and argon content inside the laser powder bed fusion LPBF 3D printer, thereby reducing oxidation reactions and improving the density and quality of printed parts; at the same time, during the printing process, the temperature of the printing substrate is set to 100-300°C, which can reduce the thermal stress during the molding of the niobium alloy, thereby improving the mechanical properties of the high-titanium nickel-niobium-based alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Flow chart of preparing high titanium nickel niobium based alloy according to the present invention;

[0024] Figure 2 : Transmission electron microscope photo of the high titanium nickel niobium based alloy prepared in Example 1 of the present invention;

[0025] Figure 3 : Tensile curves of the high titanium nickel niobium based alloy prepared in Example 1 of the present invention before and after annealing. DETAILED DESCRIPTION

[0026] The specific contents of the present invention are further explained in detail below in conjunction with embodiments.

[0027] The particle sizes of Nb powder, Ti powder and Ni powder selected in Examples 1 to 5 are all 15 to 53 um, so as to improve the printing accuracy of the laser additive manufacturing equipment.

[0028] The process flow of preparing high titanium nickel niobium based alloys according to Examples 1 to 5 is as follows: Figure 1 , wherein, in the process of preparing the high-titanium nickel-niobium-based alloy billet in step 2, the high-titanium nickel-niobium-based alloy component model is first constructed by using design software, converted into an STL file, and then imported into a laser additive manufacturing device (selective laser melting SLM device or laser powder bed melting LPBF 3D printer). After the software slices itself, the process parameters are imported into the laser additive manufacturing system, and then the niobium alloy powder is added to the powder supply cylinder and spreads the powder. After argon gas is introduced into the working chamber, the printing program is entered, and a bidirectional scanning strategy is selected in each layer of forming, and a 67° rotation is applied between layers. The powder spreading and laser scanning steps are repeated until the printing is completed to obtain a high-titanium nickel-niobium-based alloy component. After the high-titanium nickel-niobium-based alloy component is cooled for 30 minutes, the printing table is raised, the scraper is moved to the edge, and the remaining powder is swept into the residual powder cylinder with a brush. The unused powder in the powder spreading cylinder is taken out with a shovel, and the printed substrate with the printed niobium alloy component is removed, and the printed high-titanium nickel-niobium-based alloy component is cut by fast wire cutting.

[0029] The printing substrate of the laser powder bed fusion LPBF 3D printer selected in Examples 4 to 5 is made of titanium alloy.

[0030] Example 1

[0031] Step 1: In terms of atomic percentage, 70% Nb powder, 20% Ti powder and 10% Ni powder are first placed in a powder mixer and mixed for 3 hours to obtain niobium alloy powder; then the niobium alloy powder is moved to a vacuum drying oven, the power switch and vacuum pump switch of the vacuum drying oven are turned on, and the vacuum drying oven is evacuated. When the vacuum degree is 10 -6 Pa, turn off the vacuum pump switch, keep the temperature at 100℃ for 2h, after the temperature is over, turn off the power switch, wait for the vacuum drying oven to cool down to below 30℃, open the air valve, and take out the niobium alloy powder from the vacuum drying oven when the air pressure is 0;

[0032] Step 2, using a selective laser melting SLM device to make a high-titanium nickel-niobium based alloy billet from the niobium alloy powder;

[0033] The laser scanning speed of the selective laser melting SLM equipment is 500 mm / s, the powder layer thickness is 0.01 mm, the scanning interval is 0.04 mm, and the laser power is 200 W;

[0034] Step 3: Place the high-titanium-nickel-niobium alloy billet into a high-temperature furnace with high vacuum, and use a mechanical pump and a diffusion pump to make the pressure in the furnace reach 1×10 -3 Pa, the temperature was raised from room temperature to 1150°C at a heating rate of 10°C / min, annealed for 5h, and then cooled in the furnace to obtain a high-titanium nickel-niobium based alloy.

[0035] Figure 2 This is a transmission electron microscope photograph of the high titanium, nickel, and niobium-based alloy prepared in Example 1. The light-colored area in the figure is the γ matrix structure formed by the niobium element, and the dark-colored area is the Ti2Ni structure formed by the titanium and nickel elements. The γ matrix is ​​wrapped by the mesh-like Ti2Ni structure, which improves the mechanical properties of the niobium alloy.

[0036] Figure 3 The tensile curves of the high titanium nickel niobium based alloy prepared in Example 1 before and after annealing, the black color represents the tensile curve before annealing, and the red color represents the tensile curve after annealing. It can be seen that the high titanium nickel niobium based alloy after annealing has a tensile strain of 20% and a tensile strength of 625 MPa, and has excellent mechanical properties.

[0037] Example 2

[0038] Step 1: In terms of atomic percentage, 65% Nb powder, 20% Ti powder, 10% Ni powder and 5% Mo powder are first placed in a powder mixer and mixed for 5 hours to obtain niobium alloy powder; then the niobium alloy powder is moved to a vacuum drying oven, the power switch and vacuum pump switch of the vacuum drying oven are turned on, and the vacuum drying oven is evacuated. When the vacuum degree is 10 -6Pa, turn off the vacuum pump switch, keep the temperature at 100℃ for 2h, after the temperature is over, turn off the power switch, wait for the vacuum drying oven to cool down to below 30℃, open the air valve, and take out the niobium alloy powder from the vacuum drying oven when the air pressure is 0;

[0039] Step 2, using a selective laser melting SLM device to make a high-titanium nickel-niobium based alloy billet from the niobium alloy powder;

[0040] The laser scanning speed of the selective laser melting SLM equipment is 300 mm / s, the powder layer thickness is 0.03 mm, the scanning interval is 0.03 mm, and the laser power is 150 W;

[0041] Step 3: Place the high-titanium-nickel-niobium alloy billet into a high-temperature furnace with high vacuum, and use a mechanical pump and a diffusion pump to increase the pressure in the furnace to 5×10 -3 Pa, the temperature was raised from room temperature to 1100°C at a heating rate of 10°C / min, annealed for 8h, and then cooled in the furnace to obtain a high-titanium nickel-niobium based alloy.

[0042] Example 3

[0043] Step 1: In terms of atomic percentage, 60% Nb powder, 25% Ti powder, 10% Ni powder and 5% tungsten powder are first placed in a powder mixer and mixed for 6 hours to obtain niobium alloy powder; then the niobium alloy powder is moved to a vacuum drying oven, the power switch and vacuum pump switch of the vacuum drying oven are turned on, and the vacuum drying oven is evacuated. When the vacuum degree is 10 -6 Pa, turn off the vacuum pump switch, keep the temperature at 100℃ for 2h, after the temperature is over, turn off the power switch, wait for the vacuum drying oven to cool down to below 30℃, open the air valve, and take out the niobium alloy powder from the vacuum drying oven when the air pressure is 0;

[0044] Step 2, using a selective laser melting SLM device to make a high-titanium nickel-niobium based alloy billet from the niobium alloy powder;

[0045] The laser scanning speed of the selective laser melting SLM equipment is 700 mm / s, the powder layer thickness is 0.02 mm, the scanning interval is 0.08 mm, and the laser power is 250 W;

[0046] Step 3: Place the high-titanium-nickel-niobium alloy billet into a high-temperature furnace with high vacuum, and use a mechanical pump and a diffusion pump to increase the pressure in the furnace to 4×10 -3 Pa, the temperature was raised from room temperature to 1000°C at a heating rate of 10°C / min, annealed for 1h, and then cooled in the furnace to obtain a high-titanium nickel-niobium based alloy.

[0047] Example 4

[0048] Step 1: In terms of atomic percentage, 75% Nb powder, 15% Ti powder, 6% Ni powder and 4% zirconium powder are first placed in a powder mixer and mixed for 4 hours to obtain niobium alloy powder; then the niobium alloy powder is moved to a vacuum drying oven, the power switch and vacuum pump switch of the vacuum drying oven are turned on, and the vacuum drying oven is evacuated. When the vacuum degree is 10 -6 Pa, turn off the vacuum pump switch, keep the temperature at 100℃ for 2h, after the temperature is over, turn off the power switch, wait for the vacuum drying oven to cool down to below 30℃, open the air valve, and take out the niobium alloy powder from the vacuum drying oven when the air pressure is 0;

[0049] Step 2: Using a laser powder bed fusion (LPBF) 3D printer to make a high-titanium nickel-niobium based alloy billet from the niobium alloy powder;

[0050] The internal oxygen content of the laser powder bed fusion LPBF 3D printer is 10ppm, the argon content is 97%, and the temperature of the printed substrate is 300°C;

[0051] Step 3: Place the high-titanium-nickel-niobium alloy billet into a high-temperature furnace with high vacuum, and use a mechanical pump and a diffusion pump to increase the pressure in the furnace to 3×10 -3 Pa, the temperature was raised from room temperature to 1200°C at a heating rate of 10°C / min, annealed for 3h, and then cooled in the furnace to obtain a high-titanium nickel-niobium based alloy.

[0052] Example 5

[0053] Step 1: In terms of atomic percentage, 60% Nb powder, 25% Ti powder, 12.5% ​​Ni powder and 4% Mo powder are first placed in a powder mixer and mixed for 3 hours to obtain niobium alloy powder; then the niobium alloy powder is moved to a vacuum drying oven, the power switch and vacuum pump switch of the vacuum drying oven are turned on, and the vacuum drying oven is evacuated. When the vacuum degree is 10 -6 Pa, turn off the vacuum pump switch, keep the temperature at 100℃ for 2h, after the temperature is over, turn off the power switch, wait for the vacuum drying oven to cool down to below 30℃, open the air valve, and take out the niobium alloy powder from the vacuum drying oven when the air pressure is 0;

[0054] Step 2: Using a laser powder bed fusion (LPBF) 3D printer to make a high-titanium nickel-niobium based alloy billet from the niobium alloy powder;

[0055] The internal oxygen content of the laser powder bed fusion LPBF 3D printer is 100 ppm, the argon content is 97%, and the temperature of the printed substrate is 100°C;

[0056] Step 3: Place the high-titanium-nickel-niobium alloy billet into a high-temperature furnace with high vacuum, and use a mechanical pump and a diffusion pump to increase the pressure in the furnace to 2×10 -3Pa, the temperature was raised from room temperature to 1000°C at a heating rate of 10°C / min, annealed for 10 h, and then cooled in the furnace to obtain a high-titanium nickel-niobium based alloy.

[0057] In addition to annealing to strengthen the high-titanium nickel-niobium-based alloy, the high-titanium nickel-niobium-based alloy may also be strengthened by hot forging and cold rolling.

Claims

1. A method for preparing a high titanium nickel niobium based alloy, characterized in that: The steps include: Step 1, preparing niobium alloy powder and vacuum drying, wherein the atomic proportion of Nb powder in the niobium alloy powder is 60% to 75%, the atomic proportion of Ti powder in the niobium alloy powder is 15% to 25%, the atomic proportion of Ni powder in the niobium alloy powder is 6% to 12.5%, and the remainder is refractory metal element powder; Step 2: Using laser additive manufacturing equipment to make niobium alloy powder into high-titanium nickel-niobium based alloy billets; Step 3: Place the high-titanium-nickel-niobium alloy billet into a high-temperature furnace with high vacuum, and use a mechanical pump and a diffusion pump to make the pressure in the furnace reach 1×10 -3 Pa~5×10 -3 Pa, the temperature is raised from room temperature to 1000-1200°C at a heating rate of 10°C / min, annealed for 1-10h, and then cooled in the furnace to obtain a high-titanium nickel-niobium based alloy.

2. The method for preparing a high titanium nickel niobium based alloy according to claim 1, characterized in that: In step 1, the refractory metal element is tungsten, molybdenum or zirconium.

3. The method for preparing a high titanium nickel niobium based alloy according to claim 1, characterized in that: In step 1, the atomic ratio of Ti powder to Ni powder is (2-2.5):

1.

4. The method for preparing a high titanium nickel niobium based alloy according to claim 1, characterized in that: In the step 1, the particle sizes of the Nb powder, Ti powder and Ni powder are all 15-53 um.

5. The method for preparing a high titanium nickel niobium based alloy according to claim 1, characterized in that: The process of preparing the niobium alloy powder in step 1 is as follows: niobium powder, titanium powder, nickel powder and refractory metal element powder are placed in a powder mixer according to a certain proportion and mixed for 3 to 10 hours.

6. The method for preparing a high titanium nickel niobium based alloy according to claim 1, characterized in that: The vacuum drying in step 1 is performed by using a vacuum drying oven at 100° C. for 2 h.

7. The method for preparing a high titanium nickel niobium based alloy according to claim 1, characterized in that: The laser additive manufacturing equipment in step 2 is a selective laser melting SLM equipment, and its working parameters include: laser scanning speed of 300-700 mm / s, powder layer thickness of 0.01-0.03 mm, scanning spacing of 0.03-0.08 mm, and laser power of 150-250 W.

8. The method for preparing a high titanium nickel niobium based alloy according to claim 1, characterized in that: The laser additive manufacturing equipment in step 2 is a laser powder bed fusion LPBF 3D printer, the internal oxygen content of which is less than 200 ppm, and the argon content is not less than 97%, and the temperature of the printed substrate is 100-300°C.

9. The high titanium nickel niobium based alloy prepared by the method according to any one of claims 1 to 8, characterized in that: It includes a matrix and a network precipitated phase, and the matrix is ​​uniformly wrapped by the network precipitated phase.

10. The high titanium nickel niobium based alloy according to claim 9, characterized in that: The matrix is ​​γ-phase niobium, and the network precipitated phase is Ti2Ni.

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