A high-strength titanium alloy suitable for additive manufacturing

Abstract

The application discloses a high-strength titanium alloy suitable for additive manufacturing, which is composed of the following components in mass fraction: Al 4-6%, Mo 3-5%, V 3-5%, Cr 3-5%, Zr 2-4%, B 0.1-1%, and the balance of Ti and inevitable impurities. The high-strength titanium alloy of the application adds B elements, and when the high-strength titanium alloy is subjected to additive manufacturing, TiB intermetallic compounds are precipitated from the molten pool during solidification, effectively hindering the growth of original Beta grains of the titanium alloy, thereby realizing in-situ regulation of the microstructure and grain morphology under the additive manufacturing process of the alloy, significantly refining the alloy grains while improving the comprehensive mechanical properties. The addition of Cr can further improve the solid solution strengthening effect of the titanium alloy, so that the high-strength titanium alloy part obtained after additive manufacturing processing has uniform mechanical properties, and the tensile strength is not less than 1400 MPa.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-strength titanium alloy for additive manufacturing, and particularly relates to a high-strength titanium alloy suitable for additive manufacturing. BACKGROUND

[0002] Additive manufacturing is particularly suitable for the integrated forming preparation of complex metal components due to its unique processing method. Titanium alloy is widely used in the fields of aerospace and medical health, and the preparation of complex structures by additive manufacturing of titanium alloy has attracted much attention in recent years. However, the composition design of existing titanium alloy grades is often based on traditional metallurgical preparation methods, and the solidification nucleation rules under extreme metallurgical conditions of additive manufacturing are not fully considered, resulting in coarse alloy structure of the related products after additive manufacturing. At the same time, due to the influence of heat flow direction, the grain of the existing alloy after additive manufacturing shows obvious coarse columnar grain growth along the stacking direction, and the strength is low and the anisotropy is significant.

[0003] Therefore, it is urgent to develop a titanium alloy composition that can still have significant grain refinement ability under extreme metallurgical conditions of additive manufacturing. SUMMARY

[0004] The technical problem to be solved by the application is to provide a high-strength titanium alloy suitable for additive manufacturing to solve the problems of the prior art. The high-strength titanium alloy adds B element, and TiB intermetallic compound is precipitated from the molten pool during solidification when additive manufacturing is performed, effectively hindering the growth of original Beta grains of titanium alloy, thereby realizing in-situ regulation of the microstructure and grain morphology under additive manufacturing process. The high-strength titanium alloy can significantly refine the alloy grains and improve the comprehensive mechanical properties. The addition of Cr can further improve the solid solution strengthening effect of the titanium alloy, so that the high-strength titanium alloy parts obtained after additive manufacturing of the high-strength titanium alloy have uniform mechanical properties, and the tensile strength is not less than 1400 MPa.

[0005] To solve the above technical problems, the technical scheme adopted by the application is that a high-strength titanium alloy suitable for additive manufacturing is provided, and the titanium alloy is composed of the following components by mass fraction: Al 4% to 6%, Mo 3% to 5%, V 3% to 5%, Cr 3% to 5%, Zr 2% to 4%, B 0.1% to 1%, and the balance is Ti and unavoidable impurities.

[0006] The high-strength titanium alloy of the present application adds B element in the alloy, and when the high-strength titanium alloy is subjected to additive manufacturing, TiB intermetallic compound is precipitated from the molten pool during solidification, effectively hindering the growth of original Beta grains of the titanium alloy, thereby realizing in-situ regulation of the microstructure and grain morphology under the additive manufacturing process of the alloy, significantly refining the grains of the alloy while improving the comprehensive mechanical properties of the titanium alloy, and the addition of fast eutectoid element Cr can further improve the solid solution strengthening effect of the titanium alloy, so that the high-strength titanium alloy part obtained after additive manufacturing of the high-strength titanium alloy has uniform mechanical properties and a tensile strength of not less than 1400 MPa.

[0007] The high-strength titanium alloy suitable for additive manufacturing has the following characteristics: the titanium alloy is composed of the following components by mass fraction: Al 5% to 6%, Mo 4% to 5%, V 4% to 5%, Cr 4% to 5%, Zr 3% to 4%, B 0.1% to 0.4%, and the balance of Ti and unavoidable impurities.

[0008] The high-strength titanium alloy suitable for additive manufacturing has the following characteristics: the titanium alloy is composed of the following components by mass fraction: Al 5%, Mo 4%, V 4%, Cr 4%, Zr 3%, B 0.1%, and the balance of Ti and unavoidable impurities.

[0009] The high-strength titanium alloy suitable for additive manufacturing has the following characteristics: the high-strength titanium alloy part obtained by additive manufacturing of the titanium alloy has a tensile strength of not less than 1400 MPa and an elongation of not less than 3%.

[0010] The titanium alloy suitable for additive manufacturing and the high-strength titanium alloy part of the present application are prepared by the following steps:

[0011] Step one: after mixing the raw materials, vacuum consumable melting is carried out twice, and then forging and rolling are carried out to obtain a high-strength titanium alloy suitable for additive manufacturing with a diameter of 30 mm to 50 mm;

[0012] Step two: the titanium alloy obtained in step one is prepared into spherical powder with a particle size of 53 μm to 150 μm by a PREP plasma rotating electrode atomization powder preparation device;

[0013] Step three: the spherical powder obtained in step two is subjected to additive manufacturing by using an LMD laser powder feeding device to obtain a high-strength titanium alloy part.

[0014] Compared with the prior art, the present application has the following advantages:

[0015] 1. The high-strength titanium alloy of the present application adds B element, and when additive manufacturing is performed, TiB intermetallic compound is precipitated from the molten pool during solidification process, effectively hindering the growth of original Beta grains of titanium alloy, thereby realizing in-situ regulation of microstructure and grain morphology under additive manufacturing process, significantly refining alloy grains while improving comprehensive mechanical properties, so that the high-strength titanium alloy part obtained after additive manufacturing of the high-strength titanium alloy has uniform mechanical properties.

[0016] 2. The high-strength titanium alloy suitable for additive manufacturing of the present application has a tensile strength greater than 1400 MPa and an elongation greater than 3% for the high-strength titanium alloy part prepared under typical additive manufacturing process.

[0017] 3. The present application uses fast eutectoid element Cr to make the alloy obtain high strength and toughness, and simultaneously adds alloying element B to significantly refine the alloy grains and improve the strength and plasticity of the alloy.

[0018] 4. The high-strength titanium alloy part of the present application still has certain plasticity at the level of 1400 MPa, and the microstructure exhibits significant equiaxed crystal characteristics.

[0019] The technical solutions of the present application will be further described in detail below by means of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is the microstructure diagram of the high-strength titanium alloy part prepared in Example 1 of the present application.

[0021] Figure 2 is the microstructure diagram of the titanium alloy part prepared in Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0022] Example 1

[0023] This example includes the following steps:

[0024] Step one, after mixing the raw materials, vacuum consumable melting is carried out twice, and then forging and rolling are carried out to obtain a high-strength titanium alloy with a diameter of 30 mm; the high-strength titanium alloy is composed of the following mass fractions: Al 5%, Mo 4%, V 4%, Cr 4%, Zr 3%, B 0.1%, and the balance is Ti and unavoidable impurities;

[0025] Step two, the high-strength titanium alloy obtained in step one is prepared into spherical powder with a particle size D50 of 77 μm by PREP plasma rotating electrode atomization powder preparation equipment;

[0026] Step three, the spherical powder obtained in step two is used for additive manufacturing by LMD laser powder feeding equipment to obtain a high-strength titanium alloy part.

[0027] The tensile strength of the high-strength titanium alloy part prepared in the embodiment is 1463 MPa, and the elongation is 4.5%.

[0028] Figure 1 is a microstructure diagram of the high-strength titanium alloy part prepared in the embodiment 1 of the application, from which Figure 1 It can be seen that the grains inside the sample are equiaxed or spindle-shaped, and the average grain size is only 70 μm, showing a relatively uniform organizational feature.

[0029] Comparative Example 1

[0030] The comparative example includes the following steps:

[0031] Step 1, after mixing the raw materials, twice vacuum consumable melting is carried out, and then forging and rolling are carried out to obtain a titanium alloy with a diameter of 30 mm; the titanium alloy is composed of the following mass fractions: Al 5%, Mo 4%, V 4%, Cr 4%, Zr 3%, and the balance of Ti and unavoidable impurities;

[0032] Step 2, the titanium alloy obtained in step 1 is prepared into spherical powder with a particle size D50 of 77 μm by a PREP plasma rotating electrode atomization powder preparation device;

[0033] Step 3, the spherical powder obtained in step 2 is used to carry out additive manufacturing by using an LMD laser powder feeding device to obtain a titanium alloy part.

[0034] The tensile strength of the titanium alloy part prepared in the comparative example is 1120 MPa, and the elongation is 6.7%.

[0035] Figure 2 is a microstructure diagram of the high-strength titanium alloy part prepared in the comparative example 1 of the application, from which Figure 2 It can be seen that for the traditional titanium alloy alloying additive elements, the same additive manufacturing process as in the embodiment 1 is used, and the prepared sample has a coarse structure, the grains inside the sample exhibit obvious columnar crystal characteristics, the average grain width is greater than 200 μm and the length is greater than 1 mm, and the organization anisotropy is obvious.

[0036] It can be seen from the comparison between the embodiment 1 and the comparative example 1 that in the comparative example 1, since no B element is added in the titanium alloy, the tensile strength is decreased, the performance of the prepared titanium alloy part is poorer than that of the embodiment 1, which shows that adding the B element can effectively in-situ control the organization and grain morphology under the additive manufacturing process of the alloy, significantly refine the alloy grains, and improve the strength and plasticity of the alloy, and the mechanical properties of the alloy are uniform.

[0037] Embodiment 2

[0038] The embodiment includes the following steps:

[0039] Step one, after mixing the raw materials, twice vacuum consumable melting is carried out, and then forging and rolling are carried out to obtain a high-strength titanium alloy with a diameter of 40 mm; the high-strength titanium alloy is composed of the following mass fractions of components: Al 5%, Mo 3.5%, V 3.5%, Cr 3.8%, Zr 3%, B 0.3%, and the balance of Ti and unavoidable impurities;

[0040] Step two, the high-strength titanium alloy obtained in step one is prepared into spherical powder with a particle size D50 of 126 μm by a PREP plasma rotating electrode atomization powder preparation device;

[0041] Step three, the spherical powder obtained in step two is used for additive manufacturing by an LMD laser powder feeding device to obtain a high-strength titanium alloy part.

[0042] After detection, the tensile strength of the high-strength titanium alloy part prepared in this embodiment is 1455 MPa, and the elongation is 3.5%.

[0043] Example 3

[0044] This embodiment includes the following steps:

[0045] Step one, after mixing the raw materials, twice vacuum consumable melting is carried out, and then forging and rolling are carried out to obtain a high-strength titanium alloy with a diameter of 50 mm; the high-strength titanium alloy is composed of the following mass fractions of components: Al 5%, Mo 3.5%, V 3.5%, Cr 3.8%, Zr 3%, B 0.3%, and the balance of Ti and unavoidable impurities;

[0046] Step two, the high-strength titanium alloy obtained in step one is prepared into spherical powder with a particle size D50 of 126 μm by a PREP plasma rotating electrode atomization powder preparation device;

[0047] Step three, the spherical powder obtained in step two is used for additive manufacturing by an LMD laser powder feeding device to obtain a high-strength titanium alloy part.

[0048] After detection, the tensile strength of the high-strength titanium alloy part prepared in this embodiment is 1413 MPa, and the elongation is 3.8%.

[0049] Example 4

[0050] This embodiment includes the following steps:

[0051] Step one, after mixing the raw materials, twice vacuum consumable melting is carried out, and then forging and rolling are carried out to obtain a high-strength titanium alloy with a diameter of 50 mm; the high-strength titanium alloy is composed of the following mass fractions of components: Al 5%, Mo 3.5%, V 3.5%, Cr 3.8%, Zr 3%, B 0.3%, and the balance of Ti and unavoidable impurities;

[0052] Step two, the high-strength titanium alloy obtained in step one is prepared into spherical powder with a particle size D50 of 92 μm by a PREP plasma rotating electrode atomization powder preparation device;

[0053] Step three, the spherical powder obtained in step two is used for additive manufacturing by an LMD laser powder feeding device to obtain a high-strength titanium alloy part.

[0054] It is detected that the tensile strength of the high-strength titanium alloy part prepared in the embodiment is 1411 MPa, and the elongation is 3.1%.

[0055] Embodiment 5

[0056] The embodiment includes the following steps:

[0057] Step one, after the raw materials are mixed, vacuum consumable melting is carried out twice, and then forging and rolling are carried out to obtain a high-strength titanium alloy with a diameter of 50 mm; the high-strength titanium alloy is composed of the following components in mass fraction: Al 5.5%, Mo 4.5%, V 4.5%, Cr 4.5%, Zr 3.5%, B 0.4%, and the balance of Ti and inevitable impurities;

[0058] Step two, the high-strength titanium alloy obtained in step one is prepared into spherical powder with a particle size D50 of 83 μm by a PREP plasma rotating electrode atomization powder preparation device;

[0059] Step three, the spherical powder obtained in step two is used for additive manufacturing by an LMD laser powder feeding device to obtain a high-strength titanium alloy part.

[0060] It is detected that the tensile strength of the high-strength titanium alloy part prepared in the embodiment is 1432 MPa, and the elongation is 4.2%.

[0061] The above is only a preferred embodiment of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent change made according to the technical essence of the present application to the above embodiment are still within the protection scope of the technical solution of the present application.

Claims

1. A high-strength titanium alloy suitable for additive manufacturing, characterized in that, This titanium alloy consists of the following components by mass fraction. Composition: Al 4%, Mo 3%~5%, V 3%~5%, Cr 3%~5%, Zr 2%~4%, B 0.1%~1%, balance Ti and unavoidable impurities; the high-strength titanium alloy parts obtained by additive manufacturing using the above titanium alloy have a tensile strength of not less than 1400MPa and an elongation of not less than 3%; The titanium alloy and high-strength titanium alloy parts are manufactured through the following steps: Step 1: After mixing the raw materials, perform two vacuum consumable melting processes, followed by forging and rolling to obtain a high-strength titanium alloy with a diameter of 30mm~50mm suitable for additive manufacturing. Step 2: Prepare spherical powder with a particle size of 53µm~150µm using PREP plasma rotating electrode atomization powder preparation equipment to obtain the titanium alloy obtained in Step 1. Step 3: The spherical powder obtained in Step 2 is used for additive manufacturing using an LMD laser powder feeding device to obtain high-strength titanium alloy parts.

2. The high-strength titanium alloy suitable for additive manufacturing according to claim 1, characterized in that, The titanium alloy consists of the following components by mass fraction. Composition: Al 4%, Mo 4%~5%, V 4%~5%, Cr 4%~5%, Zr 3%~4%, B 0.1%~0.4%, balance Ti and unavoidable impurities.

3. A high-strength titanium alloy suitable for additive manufacturing according to claim 1, characterized in that, The titanium alloy consists of the following components by mass fraction. Composition: Al 4%, Mo 4%, V 4%, Cr 4%, Zr 3%, B 0.1%, balance Ti and unavoidable impurities.

Images