An in-situ self-generated ceramic particle reinforced low tungsten content composite material and a preparation method thereof

Abstract

The application discloses an in-situ self-generating ceramic particle reinforced low-tungsten-content composite material, and a preparation method of the in-situ self-generating ceramic particle reinforced low-tungsten-content composite material.The low-tungsten-content composite material is composed of the following components in percentage by mass: W 59% to 69%, Ni 21% to 28%, Fe 9% to 12%, and ceramic reinforcing phase 1%.The tungsten content in the material system is greatly reduced, the toughness of the bonding phase is significantly increased, the plasticity and processing performance are improved, the W atoms in the bonding phase are difficult to diffuse to the surface of other W grains during the sintering process, the long-range migration is blocked, the W grain growth is effectively inhibited, the size of the in-situ generated ceramic particles is small, the distribution is uniform, the interface between the metal matrix and the ceramic particles is pure and firm, the strong dispersion strengthening and fine-grain strengthening effects can be produced, and the application of the low-tungsten-content composite material is suitable for the fields of aerospace, radiation shielding and precision instruments.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, and in particular relates to an in-situ self-generated ceramic particle reinforced low-tungsten content composite material and its preparation method. Background Technology

[0002] High-density tungsten alloys are a typical type of two-phase composite material prepared by powder metallurgy liquid-phase sintering, with tungsten (W) as the hard phase and transition metals such as nickel (Ni) and iron (Fe) as the binder phase. Among them, the traditional alloy system with a composition of 90W-7Ni-3Fe (mass percentage) has been widely used in aerospace counterweights, kinetic energy penetrator cores, radiation shielding components, and high-precision instruments due to its high density (approximately 17.1 g / cm³), good strength, and ductility. However, with the increasingly stringent requirements for the comprehensive performance of materials in modern equipment and cutting-edge technology fields, the inherent limitations of traditional high-W content alloy systems are becoming increasingly prominent, becoming a bottleneck restricting their further development.

[0003] First, traditional high-W content alloys face an inherent contradiction between strength and ductility. W content is a core factor determining alloy performance. Related studies show that while the strength and hardness of the alloy increase from 90% to 97%, its elongation decreases significantly. This stems from the fact that an excessively high W particle volume fraction leads to a relatively insufficient binder phase, resulting in increased stress concentration during deformation and easier crack initiation and propagation. Essentially, this reflects an imbalance between the brittle W phase and the ductile binder phase. Although optimizing the sintering process or subsequent heat treatment can improve ductility to some extent, the improvement is limited and may come at the cost of sacrificing some strength.

[0004] Secondly, the processing performance and process sensitivity of traditional alloys limit their application expansion. High volume fraction of W particles results in high alloy hardness and brittleness, making them highly susceptible to microcracks during subsequent machining, thus limiting the manufacture of complex-shaped components. Simultaneously, alloy properties are extremely sensitive to sintering process parameters. Excessively high sintering temperatures or prolonged holding times lead to abnormally large W grains, severely impairing mechanical properties. Conversely, processes employed to suppress deformation and increase density (such as adding coarse W powder) may worsen interfacial bonding, resulting in a significant reduction in elongation. This narrow processing window and large performance fluctuations place extremely high demands on production quality control.

[0005] More importantly, the strengthening of traditional 90W-7Ni-3Fe alloys mainly relies on dispersion strengthening and solid solution strengthening of W particles, and its performance potential has been fully explored. Although the performance can be improved to a limited extent by adding trace alloying elements (such as Re) or by using strengthening sintering processes such as vacuum hot pressing, these are all marginal improvements to the existing system and are difficult to achieve a synergistic leapfrog improvement in key indicators such as strength, toughness, and wear resistance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an in-situ self-generated ceramic particle reinforced low-tungsten content composite material. This in-situ self-generated ceramic particle reinforced low-tungsten content composite material significantly increases the content of the toughening binder phase by reducing the W content in the material system from 90% in the traditional 90W-7Ni-3Fe alloy to 59%~69%, providing a basis for improving plasticity and processing performance. This makes it difficult for W atoms in the binder phase to diffuse to the surface of other W grains during sintering, hindering long-range migration and effectively suppressing W grain growth. The in-situ generated ceramic particles are small in size, uniformly distributed, and have a pure and strong interface with the metal matrix, producing a strong dispersion strengthening and fine-grain strengthening effect. Simultaneously, by introducing a ceramic reinforcing phase to compensate for strength, it solves the problem that traditional high-density tungsten alloys struggle to balance strength and toughness.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: an in-situ self-generated ceramic particle reinforced low-tungsten content composite material, characterized in that the low-tungsten content composite material is composed of the following components by mass percentage: W 59%~69%, Ni 21%~28%, Fe 9%~12%, and ceramic reinforcing phase 1%.

[0008] The above-mentioned in-situ self-generated ceramic particle reinforced low-tungsten content composite material is characterized in that the low-tungsten content composite material is composed of the following components by mass percentage: W 69%, Ni 21%, Fe 9%, and ceramic reinforcing phase 1%.

[0009] This invention also discloses a method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material, characterized in that the preparation method includes the following steps: Step 1: Weigh out W powder, Ni powder and Fe powder according to the target composition, mix them and then ball mill them once to obtain a mixed powder; Step 2: Mix the mixed powder obtained in Step 1 with the ceramic phase powder and then ball mill it a second time to obtain tungsten-based composite powder; Step 3: The tungsten-based composite powder obtained in Step 2 is subjected to cold isostatic pressing, and then liquid phase sintering is used to obtain a low-tungsten content composite material.

[0010] This invention provides a foundation for fundamentally improving the plasticity and processing performance of materials by reducing the W content in the material system from 90% to 59%~69% and increasing the Ni and Fe content of the binder phases to 30%~40%. Due to the high content of the binder phase, W is difficult to diffuse to the surface of other W grains in the binder phase during sintering, and long-range migration is hindered, which can effectively inhibit W grain growth and reduce the W grain size to 1 / 10 of that of traditional high W content alloys. More importantly, by introducing 1% ceramic reinforcing phase and adopting an in-situ self-generated process, the generated ceramic particles are small in size, uniformly distributed, and have a pure and strong interface with the metal matrix, which can produce strong dispersion strengthening and fine grain strengthening effects, effectively compensating for the strength loss caused by the reduction of W content.

[0011] The above-mentioned method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material is characterized in that the particle size of W powder in step one is 1μm~3μm, the particle size of Ni powder is 3μm~5μm, and the particle size of Fe powder is 3μm~5μm.

[0012] The above-mentioned method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material is characterized in that the parameters of the first ball milling in step one are: anhydrous ethanol as the milling medium, a ball-to-material ratio of 10:1, a milling time of 12h~24h, and a rotation speed of 400rpm~500rpm.

[0013] The above-mentioned method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material is characterized in that the parameters of the secondary ball milling in step two are: anhydrous ethanol as the milling medium, a ball-to-material ratio of 5:1, a milling time of 6 hours, and a rotation speed of 200 rpm to 400 rpm.

[0014] The above-mentioned method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material is characterized in that the ceramic phase powder in step two is ZrC or TiC.

[0015] The above-mentioned method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material is characterized in that the pressure of the cold isostatic pressing treatment in step three is 200MPa~300MPa, and the holding time is 10min~30min.

[0016] The above-mentioned method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material is characterized in that the liquid phase sintering process in step three is: sintering at a hydrogen atmosphere and a temperature of 1480℃~1500℃ for 0.5h~2h.

[0017] Compared with the prior art, the present invention has the following advantages: 1. This invention significantly reduces the content of the expensive W phase while increasing the proportion of the binder phase and introducing novel reinforcements to construct a more optimized multiphase composite microstructure, thereby enabling low-tungsten content composite materials to achieve superior overall performance.

[0018] 2. This invention fundamentally improves the plasticity and processing performance of the material by reducing the W content to 59%~69% and increasing the proportion of the toughening binder phase to 30%~40%. At the same time, by introducing a ceramic reinforcing phase and adopting an in-situ self-generating process, nano-sized, uniformly distributed ceramic reinforcing particles with strong interfacial bonding are generated in the low-tungsten content composite material. This achieves synergistic optimization of the composition design and multi-scale structural control of the low-tungsten content composite material, taking into account both the strength and toughness of the low-tungsten content composite material.

[0019] 3. This invention achieves a greater increase in strength by designing a synergistic mechanism of fine grain strengthening and dispersion strengthening compared to introducing ceramic reinforcing phase alone. At the same time, the high volume fraction of binder phase and the uniform and refined microstructure together ensure good plasticity, thereby achieving a synergistic improvement in high strength and high plasticity, breaking through the limitation of the traditional high-density tungsten alloy where strength and plasticity are mutually exclusive.

[0020] 4. The ZrC and TiC of the present invention can undergo in-situ decomposition during liquid phase sintering, adsorb oxygen impurities in the alloy and generate fine-sized oxides, which can more effectively pin grain boundary migration, thereby obtaining a more significant grain refinement effect. In addition, the ceramic phase generated in situ is more likely to form a coherent interface with the tungsten matrix. While strengthening the matrix, the coherent structure can also inhibit phase boundary migration and limit the coarsening of grains and the second phase.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a TEM image of the tungsten-based composite powder obtained in Example 1 of the present invention.

[0023] Figure 2 This is a SEM image of the low-tungsten content composite material obtained in Example 1 of the present invention.

[0024] Figure 3 This is a TEM image of the low-tungsten content composite material obtained in Example 1 of the present invention.

[0025] Figure 4 This is a SEM image of the 89W-7Ni-3Fe-1ZrC alloy obtained in Comparative Example 1 of this invention.

[0026] Figure 5 This is a SEM image of the 90W-7Ni-3Fe alloy obtained in Comparative Example 2 of this invention. Detailed Implementation

[0027] Example 1 The low-tungsten content composite material of this embodiment is composed of the following components by mass percentage: W 69%, Ni 21%, Fe 9%, and ceramic reinforcing phase 1%; the preparation method of this low-tungsten content composite material includes the following steps: Step 1: Weigh out W powder with a particle size of 1 μm, Ni powder with a particle size of 3 μm, and Fe powder with a particle size of 3 μm according to the target composition. Then, mix the above raw material powders by mechanical alloying and ball mill once to obtain a mixed powder. The ball milling medium is anhydrous ethanol, the ball-to-material ratio is 10:1, the ball milling time is 24 hours, and the rotation speed is 500 rpm. Step 2: The mixed powder obtained in Step 1 is mixed with ZrC nanopowder and then subjected to secondary ball milling to obtain tungsten-based composite powder; the medium for the secondary ball milling is anhydrous ethanol, the ball-to-material ratio is 5:1, the ball milling time is 6 hours, and the rotation speed is 400 rpm. Step 3: The tungsten-based composite powder obtained in Step 2 is subjected to cold isostatic pressing at 300 MPa for 10 min, followed by liquid phase sintering at 1480℃ in a hydrogen atmosphere for 1 h to obtain a low-tungsten content composite material.

[0028] The microstructure of the tungsten-based composite powder obtained in step two of this embodiment was analyzed, such as... Figure 1 As shown, the average grain size is 20 nm, with extremely small grains and a very narrow grain size division. Microscopic morphology analysis was performed on the low-tungsten content composite material obtained in this embodiment, as follows: Figure 2 As shown, the grain size is approximately 3 μm, and the distribution of the nano-second phase particles is as follows. Figure 3 As shown, the tungsten content composite material is dispersed in the metal matrix, and the tensile yield strength is 1109 MPa and the elongation is 31.6%.

[0029] Example 2 The low-tungsten content composite material of this embodiment is composed of the following components by mass percentage: W 59%, Ni 28%, Fe 12%, and ceramic reinforcing phase 1%; the preparation method of this low-tungsten content composite material includes the following steps: Step 1: Weigh out W powder with a particle size of 1 μm, Ni powder with a particle size of 3 μm, and Fe powder with a particle size of 3 μm according to the target composition. Then, mix the above raw material powders by mechanical alloying and ball mill once to obtain mixed powder. The ball milling medium is anhydrous ethanol, the ball-to-material ratio is 10:1, the ball milling time is 12 hours, and the rotation speed is 400 rpm. Step 2: The mixed powder obtained in Step 1 is mixed with ZrC nanopowder and then subjected to secondary ball milling to obtain tungsten-based composite powder; the medium for the secondary ball milling is anhydrous ethanol, the ball-to-material ratio is 5:1, the ball milling time is 6 hours, and the rotation speed is 300 rpm. Step 3: The tungsten-based composite powder obtained in Step 2 is subjected to cold isostatic pressing at 200 MPa for 10 min, followed by liquid phase sintering at 1490℃ in a hydrogen atmosphere for 1 h to obtain a low-tungsten content composite material.

[0030] Upon inspection, the average grain size of the tungsten-based composite powder doped with nano-ZrC obtained in step two of this embodiment is 45 nm; the grain size of the low-tungsten content composite material obtained in this embodiment is about 5 μm, the tensile yield strength is 1032 MPa, and the elongation is 30.9%.

[0031] Example 3 The low-tungsten content composite material of this embodiment is composed of the following components by mass percentage: W 65%, Ni 25%, Fe 9%, and ceramic reinforcing phase 1%; the preparation method of this low-tungsten content composite material includes the following steps: Step 1: Weigh out W powder with a particle size of 3μm, Ni powder with a particle size of 5μm, and Fe powder with a particle size of 5μm according to the target composition. Then, mix the above raw material powders by mechanical alloying and ball mill once to obtain mixed powder. The ball milling medium is anhydrous ethanol, the ball-to-material ratio is 10:1, the ball milling time is 24h, and the rotation speed is 400rpm. Step 2: The mixed powder obtained in Step 1 is mixed with TiC nanoparticles and then subjected to secondary ball milling to obtain tungsten-based composite powder; the medium for the secondary ball milling is anhydrous ethanol, the ball-to-material ratio is 5:1, the ball milling time is 6 hours, and the rotation speed is 200 rpm. Step 3: The tungsten-based composite powder obtained in Step 2 is subjected to cold isostatic pressing at 200 MPa for 10 min, followed by liquid phase sintering at 1500℃ in a hydrogen atmosphere for 1 h to obtain a low-tungsten content composite material.

[0032] Upon inspection, the average grain size of the tungsten-based composite powder doped with nano-TiC obtained in step two of this embodiment is 70 nm; the grain size of the low-tungsten content composite material obtained in this embodiment is about 8 μm, the tensile yield strength is 1056 MPa, and the elongation is 31.5%.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that the alloy composition is 89W-7Ni-3Fe-1ZrC.

[0034] Microscopic analysis was performed on the 89W-7Ni-3Fe-1ZrC alloy obtained in this embodiment, such as... Figure 4 As shown, the grain size is approximately 15 μm. The tensile yield strength of the 89W-7Ni-3Fe-1ZrC alloy in this comparative example was measured to be 986 MPa, and the elongation was 25.6%. Compared with the low-tungsten content composite material of Example 1, the grain size of this comparative example is larger and the mechanical properties are worse, indicating that adjusting the composition of the alloy binder phase is beneficial to refining the grains and simultaneously improving the strength and toughness of the material.

[0035] Comparative Example 2 The difference between this comparative example and Example 1 is that the alloy composition is 90W-7Ni-3Fe.

[0036] Microscopic analysis was performed on the 90W-7Ni-3Fe alloy obtained in this comparative example, such as... Figure 5 As shown, the grain size is approximately 35 μm. The tensile yield strength of the 90W-7Ni-3Fe alloy in this comparative example was measured to be 826 MPa, and the elongation was 30.2%. Compared with the 89W-7Ni-3Fe-1ZrC alloy of Comparative Example 1 and the low-tungsten content composite material of Example 1, the alloy in this comparative example has a larger grain size. This indicates that the synergistic regulation of the ceramic reinforcing phase and the increase in the proportion of the binder phase is more conducive to the grain refinement effect, significantly reduces the grain size, and simultaneously improves the strength and toughness of the material.

[0037] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An in-situ self-generated ceramic particle-reinforced low-tungsten content composite material, characterized in that, The low-tungsten content composite material is composed of the following components by mass percentage: W 59%~69%, Ni 21%~28%, Fe 9%~12%, and ceramic reinforcing phase 1%.

2. The in-situ self-generated ceramic particle-reinforced low-tungsten content composite material according to claim 1, characterized in that, The low-tungsten content composite material is composed of the following components by mass percentage: W 69%, Ni 21%, Fe 9%, and ceramic reinforcing phase 1%.

3. A method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material as described in claim 1 or 2, characterized in that, The preparation method includes the following steps: Step 1: Weigh out W powder, Ni powder and Fe powder according to the target composition, mix them and then ball mill them once to obtain a mixed powder; Step 2: Mix the composite powder obtained in Step 1 with the ceramic phase powder and then ball mill it a second time to obtain tungsten-based composite powder; Step 3: The tungsten-based composite powder obtained in Step 2 is subjected to cold isostatic pressing, and then liquid phase sintering is used to obtain a low-tungsten content composite material.

4. The method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material according to claim 3, characterized in that, The particle size of W powder mentioned in step one is 1μm~3μm, the particle size of Ni powder is 3μm~5μm, and the particle size of Fe powder is 3μm~5μm.

5. The method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material according to claim 3, characterized in that, The parameters for the first ball milling in step one are: anhydrous ethanol as the milling medium, ball-to-material ratio of 10:1, milling time of 12h~24h, and rotation speed of 400rpm~500rpm.

6. The method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material according to claim 3, characterized in that, The parameters for the secondary ball milling in step two are: anhydrous ethanol as the milling medium, a ball-to-material ratio of 5:1, a milling time of 6 hours, and a rotation speed of 200 rpm to 400 rpm.

7. The method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material according to claim 3, characterized in that, The ceramic phase powder mentioned in step two is ZrC or TiC.

8. The method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material according to claim 3, characterized in that, The pressure for the cold isostatic pressing process in step three is 200MPa~300MPa, and the holding time is 10min~30min.

9. The method for preparing an in-situ self-generated ceramic particle-reinforced low-tungsten content composite material according to claim 3, characterized in that, The liquid phase sintering process described in step three is as follows: sintering at a hydrogen atmosphere and at 1480℃~1500℃ for 0.5h~2h.

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