Nanoparticle reinforced titanium-based composite powder and preparation method thereof

Abstract

The invention belongs to the technical field of composite material processing, and particularly relates to nano-particle reinforced titanium-based composite material powder and a preparation method. The method comprises the following steps: S1, selecting over-specification powder of which the contents of oxygen, nitrogen and hydrogen elements are lower than set values; s2, calculating a rare earth reactant adapted to be subjected to oxidation reaction based on the oxygen content of the over-specification powder; s3, the mixture of the super-specification powder and the rare earth reactant is ground for 6-12 hours; s4, the ground powder is poured into a large-size sintering mold with multiple cavities, the large-size sintering mold is put into a hot-pressing sintering furnace for high-temperature sintering, and an electrode is formed; and S5, preparing the electrode into composite material powder by adopting powder preparation modes such as gas atomization or electrode rotation. According to the method, the manufacturing cost of the nano-particle reinforced titanium-based composite material powder is reduced, and the electrode preparation process is shortened.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of composite material processing, and particularly relates to a kind of nano-particle reinforced titanium matrix composite powder and preparation method. BACKGROUND

[0002] The nano-particle reinforced titanium matrix composite powder has the advantages of high surface quality, small size of reinforcing body, and strong designability of organizational configuration, and is considered as an ideal raw material for additive manufacturing and powder metallurgy processes. The titanium matrix composite prepared therefrom has the advantages of small organization, good strength and plasticity, and high temperature strength, which makes up for the performance short board of traditional micron reinforced titanium matrix composite, and is gradually applied to the preparation of high-performance titanium matrix composite and components. However, the existing nano-particle reinforced titanium matrix composite powder is usually prepared by multiple melting-forging-machining-atomization processes, i.e., first, a titanium matrix composite ingot is prepared by melting to realize in-situ compounding, then an electrode required for powder preparation is obtained by hot deformation and mechanical processing, and finally, the composite powder is prepared by gas atomization or rotating electrode process. The raw material cost is high, the preparation process is complex, the material utilization rate is low, the powder cost is high, and the large-scale application is limited.

[0003] Using the existing alloy powder preparation process, 20% to 30% of oversized powders such as oversized particle powders, hollow powders, and irregular powders are generated in the powder preparation process, which cannot be directly used for additive manufacturing. Such powders are extremely low in price and are often directly recycled or used for the preparation of low-quality materials. If such powders can be used for the preparation of composite powders through scientific design, not only the manufacturing cost can be reduced, but also the economic value of the products can be increased, which will bring great economic value. SUMMARY

[0004] To solve the above problems, the application provides a nano-particle reinforced titanium matrix composite powder and a preparation method, to prepare high-quality nano-particle reinforced titanium matrix composite powder and realize low-cost batch production of nano-particle reinforced titanium matrix composite powder.

[0005] The first aspect of the application provides a nano-particle reinforced titanium matrix composite powder preparation method, characterized in that it comprises:

[0006] Step S1, selecting oversized powders with oxygen, nitrogen, and hydrogen element contents lower than the set values;

[0007] Step S2, calculating a rare earth reaction agent for adapting to oxidation reaction based on the oxygen content of the oversized powders;

[0008] Step S3, grinding the mixture of the oversized powders and the rare earth reaction agent for 6-12 hours;

[0009] Step S4, pour the ground powder into a large size sintering mold with multiple cavities, and put into a hot-press sintering furnace for high temperature sintering to form an electrode, the sintering temperature is T β +T A , T β is a phase transition temperature of titanium alloy, T A is 50-150℃, time is 2-8h, pressure is 20-100MPa, and vacuum degree is not higher than 10 -4 Pa;

[0010] Step S5, prepare the electrode into a composite material powder by using a gas atomization or a rotating electrode powder preparation method.

[0011] Preferably, in step S1, the oversized powder includes oversized particle diameter powder of 200μm or above, hollow powder, or irregular powder.

[0012] Preferably, in step S1, the oxygen element content in the oversized powder is controlled to be below 0.2%, the nitrogen element content is controlled to be below 0.05%, and the hydrogen element content is controlled to be below 0.015%.

[0013] Preferably, the rare earth reaction agent includes a cerium group rare earth reaction agent or a yttrium group rare earth reaction agent.

[0014] Preferably, step S3 further includes adding B4C, B powder or Si powder reaction agent into the mixture.

[0015] Preferably, in step S3, the mixture is ground in a ball mill tank, the ball mill tank is provided with alloy balls, the rotation speed of the ball mill tank is 60-200r / min, and the grinding is performed under vacuum or inert gas protection.

[0016] Preferably, step S3 further includes:

[0017] Based on the difference between the metal content of the titanium-based composite material to be prepared and the content of the corresponding metal in the oversized powder, the pure metal powder of the corresponding metal is supplemented.

[0018] The second aspect of the present application provides a nanoparticle reinforced titanium-based composite material powder prepared by using the above method.

[0019] The present application reduces the manufacturing cost of the nanoparticle reinforced titanium-based composite material powder and shortens the electrode preparation process. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a flow chart of a preferred embodiment of the nanoparticle reinforced titanium-based composite material powder preparation method of the present application. DETAILED DESCRIPTION

[0021] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. Identical or similar labels in the drawings represent identical or similar elements or elements with identical or similar functions throughout. The described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0022] The first aspect of the present application provides a method for preparing a nanoparticle reinforced titanium-based composite powder, as shown in the formula mainly comprising: Figure 1

[0023] Step S1, selecting an oversized powder with oxygen, nitrogen and hydrogen element contents lower than the set values;

[0024] Step S2, calculating a rare earth reaction agent for adapting to the oxidation reaction based on the oxygen content of the oversized powder;

[0025] Step S3, grinding the mixture of the oversized powder and the rare earth reaction agent for 6-12 hours;

[0026] Step S4, pouring the ground powder into a large-size sintering mold with multiple cavities and placing it into a hot-pressing sintering furnace for high-temperature sintering to form an electrode, and the sintering temperature is T β +T A , wherein T β is the phase transition temperature of the titanium alloy, T A is 50-150℃, the time is 2-8h, the pressure is 20-100MPa, and the vacuum degree is not higher than 10 -4 Pa;

[0027] Step S5, preparing the electrode into a composite material powder by using a gas atomization or a rotating electrode powdering method.

[0028] The present application can reduce the oxygen content of the matrix, promote the uniform diffusion of elements, effectively solve the problem of waste of existing oversized powders, and prepare products with high economic value, thereby effectively realizing the scientific reuse of oversized powders in additive manufacturing.

[0029] ​First, in step S1, an existing oversized powder that cannot be used for additive manufacturing is selected as a raw material for preparing the titanium matrix composite powder of the present application. In some optional embodiments, the oversized powder includes oversized powder with a particle size of 200 pm or more, hollow powder, or irregular powder. The powder categories include oversized titanium alloy powder and various oversized pure metal powders required for preparing titanium alloys.

[0030] Before selection, the types of alloying elements in the powder should be determined, and the contents of alloying elements and impurities such as O, N, and H should be detected. In some optional embodiments, in step S1, the oxygen content in the oversized powder is controlled to be less than or equal to 0.2%, the nitrogen content is controlled to be less than or equal to 0.05%, and the hydrogen content is controlled to be less than or equal to 0.015%. Powders that do not meet the requirements are considered unqualified and are not selected.

[0031] Then, in step S2, the oxygen content in the matrix is reduced by using a rare earth reagent that can react with oxygen in the alloy at high temperature. In some optional embodiments, the rare earth reagent includes a cerium group rare earth reagent or a yttrium group rare earth reagent. Among them, La, Nd, and other rare earth reagents such as LaB6 are preferentially selected in the cerium group rare earth. Yttrium group rare earths preferentially select Y rare earth reagents.

[0032] According to the oxygen content test results of the powder in step S1, the oxygen content of the matrix alloy is denoted as A%. Taking LaB6 rare earth reagent as an example, to reduce the oxygen content in the matrix, according to the reaction 2LaB6+3[O]+12Ti→La2O3+12TiB, it is calculated that the mass fraction of added LaB6 powder is about 8.54A%, which is equivalent to the mass fraction of La2O3 reinforcement of 6.79A% and the mass fraction of TiB reinforcement of 7.63A%. The LaB6 used in the present application can react with oxygen in the matrix alloy in situ at high temperature, which not only effectively reduces the oxygen content in the matrix, but also generates La2O3 and TiB two kinds of reinforcement to achieve the purpose of strengthening.

[0033] In some optional embodiments, step S3 further includes adding B4C, B powder, or Si powder reagents to the mixture. This embodiment introduces a reinforcement reagent to achieve multi-element composite reinforcement.

[0034] In some optional embodiments, step S3 further includes:

[0035] Based on the difference between the metal content of the titanium matrix composite to be prepared and the content of the corresponding metal in the oversized powder, the pure metal powder of the corresponding metal is supplemented.

[0036] In this embodiment, the alloy powder with the most similar composition to the base alloy is selected as the main material. According to the difference between the actual alloy element content measured in step S1 and the theoretical content, the corresponding mass of oversized pure metal powder is supplemented.

[0037] In an alternative embodiment, the corresponding oversized pure metal powder can also be directly weighed according to the required alloy composition, and then the corresponding mass of LaB6, B4C and other reactant powders is weighed according to the designed reinforcement content.

[0038] In some optional embodiments, the mixture is ground in a ball mill tank provided with alloy balls in step S3, and the rotation speed of the ball mill tank is 60-200 r / min. Vacuum or inert gas protection is used during grinding.

[0039] In this embodiment, the mixture is thoroughly mixed in a horizontal ball mill or a new type of ball mill. If oversized pure metal powder is used, hard alloy balls need to be added for ball milling to ensure that the alloy elements are fully diffused during sintering, making the alloy element distribution more uniform, and the ball-to-material ratio is > 1:2. Vacuum or Ar gas protection is used during ball milling, and the ball-milled mixture is sealed and stored in a sealed bag. The mixing time is 6-12 hours, which can ensure that all types of metal powders and reinforcement reactants are uniformly mixed, and the distribution of the reinforcement after reaction is uniform.

[0040] Then, hot-pressing sintering is performed in step S4 to prepare the electrode. According to the required electrode size for powdering, a large-size sintering mold containing multiple cavities like honeycomb coal is designed, the number of cavities is 4-12, and the thickness of the inter-cavity wall and the outer wall of the mold needs to meet the strength design requirements to realize batch production of the same size electrode; the same mass of mixed powder is weighed and poured into the mold cavities, and after filling and assembly, it is placed into a hot-pressing sintering furnace; the sintering parameters given in step S4 can ensure that the in-situ reaction proceeds fully and the alloy elements diffuse uniformly. After sintering, there is a carbonized layer and an oxidized layer on the surface of the billet, which needs to be machined to remove defects and impurities.

[0041] Finally, powder preparation is performed in step S5. After powdering, powders of different particle sizes are screened, and the alloy element content and the impurity content of O, N and H are detected. If the detected O content is B%, the O content increment after powdering is B-A%, and since the O in the raw material has reacted with LaB6 to form La2O3, the O content increment is the theoretical O content in the alloy matrix. The alloy element content range meets the theoretical design requirements, the O content increment is <0.1%, the N content is <0.05%, and the H content is <0.015%.

[0042] It should be noted that after step S5, it is necessary to determine whether the prepared powder meets the standard by detecting the oxygen increment. If the oxygen increment exceeds 0.1%, it indicates that the rare earth reagent ratio is inaccurate or the chemical reaction is insufficient, and the rare earth reagent increment needs to be recalculated according to the oxygen increment, and the above steps are re-executed.

[0043] The second aspect of the present application provides a nanoparticle reinforced titanium matrix composite powder prepared by using the above method.

[0044] The product prepared at low cost can be used for powder metallurgy or additive manufacturing to prepare high-performance nanoparticle reinforced titanium matrix composite materials, which has high economic value.

[0045] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for preparing a nanoparticle-reinforced titanium matrix composite powder, characterized in that, The method comprises the following steps: S1, selecting oversized powders with oxygen, nitrogen and hydrogen contents lower than the set values; S2, calculating rare earth reactants for adapting to the oxidation reaction based on the oxygen content of the oversized powders; S3, grinding the mixture of the oversized powders and the rare earth reactants for 6-12 hours; Step S4, pour the ground powder into a large size sintering mold with multiple cavities, and put it into a hot-pressing sintering furnace for high-temperature sintering to form an electrode, and the sintering temperature is T β +T A , wherein T β is the phase transition temperature of the titanium alloy, T A is 50-150℃, the time is 2-8h, the pressure is 20-100MPa, and the vacuum degree is not higher than 10 -4 Pa. S5, preparing the electrode into composite powders by using gas atomization or rotating electrode powdering method.

2. The nanoparticle-reinforced titanium matrix composite powder production method according to claim 1, wherein In step S1, the oversized powders include oversized powders with particle sizes larger than 200 μm, hollow powders or irregular powders.

3. The nanoparticle-reinforced titanium matrix composite powder production method according to claim 1, wherein In step S1, the oxygen content in the oversized powders is controlled to be lower than 0.2%, the nitrogen content is controlled to be lower than 0.05%, and the hydrogen content is controlled to be lower than 0.015%.

4. The nanoparticle-reinforced titanium matrix composite powder production method according to claim 1, wherein The rare earth reactants include cerium group rare earth reactants or yttrium group rare earth reactants.

5. The nanoparticle-reinforced titanium matrix composite powder production method according to claim 1, wherein In step S3, B4C, B powder or Si powder reactants are further added into the mixture.

6. The nanoparticle-reinforced titanium matrix composite powder production method according to claim 1, wherein In step S3, the mixture is ground in a ball mill tank provided with alloy balls, and the rotation speed of the ball mill tank is 60-200 r / min. The grinding is performed under vacuum or inert gas protection.

7. The nanoparticle-reinforced titanium matrix composite powder production method according to claim 1, wherein In step S3, the mixture is further ground by adding B4C, B powder or Si powder reactants. The method is prepared by using the method according to any one of claims 1-7.

8. A nanoparticle-reinforced titanium matrix composite powder, characterized in that, ​

Images