Reinforced phase directionally arranged titanium-based composite material and method of making same

Abstract

The present application relates to non-ferrous metal processing technical field, specifically to a kind of titanium matrix composite with enhanced phase directional arrangement and preparation method thereof.The method includes the following steps: step one, according to the designed TiBw volume fraction conversion required in-situ reactant powder and titanium alloy powder ratio and weighing, obtain raw material powder;Step two, the raw material powder is ball milled using planetary ball mill under high-purity Ar protective atmosphere, obtain the powder after ball milling;Step three, the powder after ball milling is heat pressed and sintered using vacuum hot-pressing sintering furnace, obtain dense titanium matrix composite;Step four, the prepared titanium matrix composite is unidirectionally forged using hydraulic press, obtain multi-level multi-scale titanium matrix composite.The matrix structure of the present application after composite forging is composed of lamellar alpha and transformed beta structure, and TiBw reinforcing phase is linearly arranged along the forging direction, uniformly distributed, and titanium matrix composite with excellent mechanical properties is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-ferrous metal processing, in particular to a titanium-based composite material with directional arrangement of reinforcing phases and a preparation method thereof. BACKGROUND

[0002] Titanium alloy, especially high-temperature titanium alloy, has a small density, corrosion resistance, high high-temperature mechanical properties and high-temperature creep resistance, and can be used as a high-temperature structural material for modern aero-engines. High-temperature titanium-based composite materials have a wide application prospect in the field of aerospace due to their excellent mechanical properties, and in recent years, near-alpha titanium-based composite materials have become a research hotspot. However, as the use temperature increases, the thermal strength and thermal stability of the titanium-based composite material are difficult to balance, resulting in a 650℃ thermal barrier temperature, which limits its application and development.

[0003] TiB whiskers have high elastic modulus, physical properties similar to titanium alloy, and good thermodynamic compatibility, and are commonly used as reinforcing phases. However, the titanium-based composite material with uniformly distributed reinforcing phases prepared by previous powder metallurgy has a certain strength improvement, but the plasticity is greatly reduced. The patent CN101333607A proposes a preparation method of TiBw / Ti alloy-based composite material, which is designed according to the grain boundary strengthening theory. The fiber network structure formed by TiB whiskers can not only improve the performance but also reduce the loss of plasticity.

[0004] Secondary thermal deformation processing, such as forging, rolling and extrusion, can effectively reduce the defects generated during the preparation of the as-cast or sintered composite material, improve the material density, refine the microstructure of the matrix, and improve the distribution state of the reinforcing phase, thereby improving the comprehensive mechanical properties of the composite material. Compared with other thermal deformation methods, hot forging is considered to be the best processing method to improve the performance of the composite material. SUMMARY

[0005] The present application relates to the technical field of non-ferrous metal processing, in particular to a titanium-based composite material with directional arrangement of reinforcing phases and a preparation method thereof.

[0006] The technical solution of the present application is as follows:

[0007] A titanium-based composite material with directional arrangement of reinforcing phases, the matrix structure after forging of the composite material is composed of lamellar alpha and transformed beta structure, and the TiBw reinforcing phase is linearly arranged and uniformly distributed along the forging direction.

[0008] The titanium-based composite material with oriented reinforcing phase has an α-lamellae with a width of 0.5–5 μm and a length of 5–30 μm, and the TiBw reinforcing phase has a volume fraction of 2–8%.

[0009] The aforementioned titanium-based composite material with oriented reinforcing phase has a density ≤ 4.6 g / cm³. 3 Tensile strength at room temperature ≥1200MPa, tensile strength at 700℃ ≥500MPa.

[0010] The preparation method of the titanium-based composite material with oriented reinforcing phase includes the following steps:

[0011] Step 1: Calculate the required ratio of in-situ reactant powder to titanium alloy powder according to the designed TiBw volume fraction and weigh them to obtain the raw material powder; the in-situ reactant powder specifically refers to B powder or TiB2 powder, and the titanium alloy powder is spherical titanium alloy powder, with the nominal composition of spherical titanium alloy powder being Ti-6Al-2.8Sn-4Zr-0.4Mo-0.5Si;

[0012] Step 2: The raw material powder is ball-milled in a planetary ball mill under a high-purity Ar protective atmosphere to obtain the ball-milled powder.

[0013] Step 3: The ball-milled powder is hot-pressed and sintered in a vacuum hot-pressing sintering furnace to obtain a dense titanium-based composite material;

[0014] Step 4: The prepared titanium-based composite material is unidirectionally forged using a hydraulic press to obtain a titanium-based composite material with oriented reinforcing phases.

[0015] In the preparation method of the titanium-based composite material with oriented reinforced phase, in step one, the volume fraction of TiBw is 2-8%, the size of the in-situ reactant powder is 0.5-3 μm, the powder morphology is irregular particles, and the diameter of the spherical titanium alloy powder is 75-200 μm.

[0016] In the preparation method of the titanium-based composite material with oriented reinforced phase, in step two, the ball milling speed is 150-250 r / min, the ball milling time is 3-5 h, and the ball-to-material mass ratio is 5:1.

[0017] In the preparation method of the titanium-based composite material with oriented reinforced phase, in step three, the maximum powder sintering temperature is 1000-1300℃, the sintering pressure is 20-50MPa, and the sintering time is 0.5-2h.

[0018] In the preparation method of the titanium-based composite material with oriented reinforced phase, step three yields a dense titanium-based composite material with a network structure of TiBw / Ti, where the network structure consists of TiB whiskers located at the original β grain boundaries.

[0019] In the preparation method of the titanium matrix composite material with oriented reinforcing phase, step four involves a unidirectional forging temperature of 1000–1200℃ and a strain rate of 0.1–2 s. -1 The deformation is 40% to 60%.

[0020] The design concept of this invention is:

[0021] This invention leverages the quasi-continuous network distribution of the reinforcing phase to address the bottleneck issue of high brittleness in titanium-based composites prepared by powder metallurgy. While refining the material microstructure, it maintains the connectivity of the matrix, achieving a synergistic improvement in both strength and ductility. Furthermore, unidirectional forging further enhances the material's ductility, resulting in large deformation and further refining the grain size and microstructure. By controlling the distribution of the reinforcing phase, the strengthening and toughening effects of the titanium-based composite are further improved. The oriented TiBw maintains good bonding with the matrix, effectively bearing loads and thus enhancing the mechanical properties of the composite.

[0022] The advantages and beneficial effects of this invention are:

[0023] Compared with existing mesh titanium-based composite materials, this invention increases the content of the reinforcing phase, obtains a reinforcing phase with a high aspect ratio, and improves the distribution of the reinforcing phase through forging process, thereby achieving simultaneous improvement in room temperature strength and high temperature strength, and enhancing the overall mechanical properties of the material. Attached Figure Description

[0024] Figure 1 This is a flowchart of the process for preparing the titanium-based composite material with oriented reinforcing phase according to the present invention.

[0025] Figure 2 This is a SEM image of the microstructure of the titanium matrix composite material with oriented reinforcing phase prepared in Example 1.

[0026] Figure 3 These are the tensile stress-strain curves of the materials in Example 1 and the comparative experimental group at room temperature and 700°C. Detailed Implementation

[0027] like Figure 1 As shown in the figure, a flowchart of a method for preparing a titanium-based composite material with oriented reinforced phases provided by an embodiment of the present invention is presented. The method includes the following steps:

[0028] S100. Calculate the required ratio of in-situ reactant powder to titanium alloy powder according to the designed TiBw volume fraction, weigh the powder, and obtain the raw material powder.

[0029] S200. The raw material powder is ball-milled in a planetary ball mill under a protective atmosphere of high-purity Ar (volume purity 99.999%) to obtain the ball-milled powder.

[0030] S300: The ball-milled powder is hot-pressed and sintered in a vacuum hot-pressing sintering furnace to obtain a dense titanium-based composite material.

[0031] S400: The prepared composite material is unidirectionally forged using a hydraulic press to obtain a titanium-based composite material with multi-level, multi-scale reinforcing phases arranged in an oriented manner.

[0032] The present invention will be further described in detail below through embodiments.

[0033] Example 1:

[0034] In this embodiment, boron powder and titanium alloy powder (titanium alloy grade TA15) were used as raw materials. The average particle size of boron powder was 0.5 μm, and the average particle size of titanium alloy powder was 75 μm. The theoretical content of the reinforcing phase was 3 vol.%. Low-energy ball milling was performed at a ball-to-material mass ratio of 5:1, a rotation speed of 220 r / min, and a time of 5 h. The reactive hot-pressing sintering temperature was 1300 °C, the sintering pressure was 50 MPa, and the sintering time was 90 min. A TiBw / Ti composite material with a network structure was prepared, wherein the network structure consists of TiB whiskers located at the original β grain boundaries.

[0035] The composite material was unidirectionally forged using a 500-ton hydraulic press at a forging temperature of 1200℃, a deformation rate of 50%, and a strain rate of 0.5s. -1 Ultimately, a titanium-based composite material with a directional arrangement of reinforcing phases is obtained. For example... Figure 2 As shown, the SEM image of the microstructure of the titanium matrix composite material with oriented reinforcing phase prepared in Example 1 is obtained from... Figure 2 It can be seen that the matrix structure of the composite material after forging also consists of lamellar α and transformed β structures. The width (0.5–5 μm) and length (5–30 μm) of the α lamellae are also refined. Furthermore, the TiBw reinforcing phase is oriented along the forging direction and is relatively uniformly distributed. The density of the composite material is 4.6 g / cm³. 3 .like Figure 3 As shown, the tensile strength of Example 1 is 1261 MPa at room temperature and 518 MPa at 700°C.

[0036] Comparative experimental group:

[0037] Using titanium alloy powder with a nominal composition of Ti-6Al-2.8Sn-4Zr-0.4Mo-0.5Si as the raw material, a reactive hot-pressing sintering process was conducted at a temperature of 1300℃, a pressure of 50MPa, and a time of 90min. The resulting alloy material was then unidirectionally forged using a 500-ton hydraulic press at a forging temperature of 1200℃ and a deformation of 50%, ultimately yielding the alloy material. The microstructure of the forged alloy still consisted of lamellar α-structure and transformed β-structure. The width of the α-lamellae decreased from 100μm in the sintered state to approximately 20μm, indicating that hot forging can effectively refine the grains and microstructure. Figure 3 As shown, the tensile strength of this material is 1059 MPa at room temperature and 416 MPa at 700℃.

[0038] Example 2:

[0039] In this embodiment, TiB2 powder and titanium alloy powder (titanium alloy grade TC4) were used as raw materials. The average particle size of TiB2 powder was 0.5 μm, and the average particle size of titanium alloy powder was 75 μm. The theoretical content of the reinforcing phase was 5 vol.%. Low-energy ball milling was performed at a ball-to-material mass ratio of 5:1, a rotation speed of 200 r / min, and a time of 4 h. The reactive hot-pressing sintering temperature was 1200 °C, the sintering pressure was 50 MPa, and the sintering time was 90 min, thus preparing a TiBw / Ti composite material with a network structure.

[0040] The composite material was unidirectionally forged using a 500-ton hydraulic press at a forging temperature of 1100℃, a deformation of 40%, and a strain rate of 0.1 s⁻¹. -1 Finally, a titanium-based composite material with oriented reinforcing phases was obtained. The TiBw reinforcing phases were oriented along the forging direction and were relatively uniformly distributed. In this embodiment, the tensile strength at room temperature was 1283 MPa, and the tensile strength at 700°C was 527 MPa.

[0041] Example 3:

[0042] In this embodiment, TiB2 powder and titanium alloy powder (titanium alloy grade TC6) were used as raw materials. The average particle size of TiB2 powder was 1 μm, and the average particle size of titanium alloy powder was 150 μm. The theoretical content of the reinforcing phase was 5 vol.%. Low-energy ball milling was performed at a ball-to-material mass ratio of 5:1, a rotation speed of 220 r / min, and a time of 5 h. The reactive hot-pressing sintering temperature was 1300 °C, the sintering pressure was 30 MPa, and the sintering time was 90 min. A TiBw / Ti composite material with a network structure was prepared.

[0043] The composite material was unidirectionally forged using a 500-ton hydraulic press at a forging temperature of 1100℃, a deformation rate of 60%, and a strain rate of 0.2 s⁻¹. -1Finally, a titanium-based composite material with oriented reinforcing phases was obtained. The TiBw reinforcing phases were oriented along the forging direction and were relatively uniformly distributed. In this embodiment, the tensile strength at room temperature was 1230 MPa, and the tensile strength at 700°C was 506 MPa.

[0044] The results show that, in order to address the bottleneck of existing titanium alloy materials' inability to operate at temperatures exceeding 600℃, the traditional titanium-based composite materials suffer from poor strengthening effects, and the high density of high-temperature alloys, this invention uses high-temperature titanium alloys and boron sources as raw materials. Through powder metallurgy, TiBw is targeted and introduced into the grain boundaries of the material, resulting in a larger aspect ratio (range of 5–10) for the reinforcement. By unidirectional forging of the composite material, a reinforcing phase with linear directional arrangement is controlled, ultimately yielding a titanium-based composite material with excellent mechanical properties.

Claims

1. A titanium-based composite material with reinforced phase orientation, characterized in that, The matrix structure of the composite material after forging consists of lamellar α and transformed β structures, and the TiBw reinforcing phase is linearly oriented and uniformly distributed along the forging direction; The preparation method of the titanium-based composite material with oriented reinforcing phase includes the following steps: Step 1: Calculate the required ratio of in-situ reactant powder to titanium alloy powder according to the designed TiBw volume fraction and weigh them to obtain the raw material powder; the in-situ reactant powder specifically refers to B powder or TiB2 powder, and the titanium alloy powder is spherical titanium alloy powder, with the nominal composition of spherical titanium alloy powder being Ti-6Al-2.8Sn-4Zr-0.4Mo-0.5Si; Step 2: The raw material powder is ball-milled in a planetary ball mill under a high-purity Ar protective atmosphere to obtain the ball-milled powder. Step 3: The ball-milled powder is hot-pressed and sintered in a vacuum hot-pressing sintering furnace to obtain a dense titanium-based composite material. The obtained dense titanium-based composite material has a network structure TiBw / Ti, and the network structure is TiB whiskers located at the original β grain boundaries. Step 4: The prepared titanium-based composite material is unidirectionally forged using a hydraulic press to obtain a titanium-based composite material with oriented reinforcing phases. The α-lamellae have a width of 0.5–5 μm and a length of 5–30 μm, and the volume fraction of the TiBw reinforcing phase is 2–8%. The density of this composite material is ≤4.6 g / cm³. 3 Tensile strength at room temperature ≥1200MPa, tensile strength at 700℃ ≥500MPa.

2. The titanium-based composite material with oriented reinforcing phase according to claim 1, characterized in that, In step one, the volume fraction of TiBw is 2-8%, the size of the in-situ reactant powder is 0.5-3 μm, the powder morphology is irregular particles, and the diameter of the spherical titanium alloy powder is 75-200 μm.

3. The titanium-based composite material with oriented reinforcing phase according to claim 1, characterized in that, In step two, the ball milling speed is 150–250 r / min, the ball milling time is 3–5 h, and the ball-to-material mass ratio is 5:

1.

4. The titanium-based composite material with oriented reinforcing phase according to claim 1, characterized in that, In step three, the maximum temperature for powder sintering is 1000–1300℃, the sintering pressure is 20–50 MPa, and the sintering time is 0.5–2 h.

5. The titanium-based composite material with oriented reinforcing phase according to claim 1, characterized in that, In step four, the unidirectional forging temperature is 1000–1200℃, and the strain rate is 0.1–2 s. -1 The deformation is 40% to 60%.

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