In-situ multiphase synergic composite anti-friction high-strength aluminum alloy composite material and forming method

Abstract

The application discloses an in-situ multiphase synergic composite wear-reducing high-strength aluminum alloy composite material and a forming method thereof. The aluminum alloy composite material comprises an aluminum alloy base, in-situ wear-reducing phases Ti2AlN and Ti2SiN and a ceramic strengthening phase AlN. The forming method comprises the following steps: after aluminum-silicon alloy powder treated by rolling and nano TiH2 powder are mixed by ball milling, the mixed powder is melted by scanning a high-energy laser beam on the surface of the mixed powder in a mixed gas environment of nitrogen and argon; hydrogen gas decomposed from the TiH2 powder covers the aluminum alloy, effectively preventing trace oxygen in the atmosphere or the powder from oxidizing the aluminum alloy at high temperature; on the other hand, Ti decomposed from the TiH2 powder, nitrogen and the aluminum-silicon alloy are in-situ reacted to form the wear-reducing phases Ti2AlN and Ti2SiN with a layered lubricating function by high-temperature induction of the laser beam, so that the aluminum alloy is endowed with wear resistance; and meanwhile, the in-situ formed AlN ceramic phase also effectively enhances the strength of the aluminum alloy.

Description

Technical Field

[0001] This invention relates to an aluminum alloy composite material and its forming method, and particularly to an in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material and its forming method. Background Technology

[0002] Aluminum alloys, due to their low density, light weight, and good thermal conductivity, along with certain strength, hardness, and corrosion resistance, are widely used in the automotive industry for manufacturing parts subjected to sliding friction. However, compared to metals such as steel and titanium alloys, aluminum alloys have lower strength and exhibit a higher wear rate, limiting their use in high-lifespan automotive components such as pistons and cylinders. Ceramic phases, with their high melting point, high elastic modulus, high hardness, and high wear resistance, have become the primary material for improving the strength and wear resistance of aluminum alloys. Typical ceramic particles include alumina, ZrB2, SiC, TiC, and graphite, which improve the wear resistance of aluminum alloys to some extent. However, microscopic observation reveals a weak interface between ceramics and aluminum alloys, making them prone to cracking under high stress loads, ultimately leading to premature failure of the aluminum alloy material, thus hindering effective strength improvement. Furthermore, due to the high reactivity of aluminum, it readily reacts with oxygen during the smelting process, forming impurities that remain in the aluminum alloy matrix, making it difficult to improve its mechanical properties and consequently affecting the service performance and lifespan of aluminum alloy components. Summary of the Invention

[0003] Purpose of the invention: The present invention aims to provide an in-situ multiphase synergistic composite wear-reducing high-strength aluminum alloy composite material with excellent wear resistance and strength; another purpose of the present invention is to provide a forming method for the in-situ multiphase synergistic composite wear-reducing high-strength aluminum alloy composite material.

[0004] Technical solution: The in-situ multiphase synergistic composite wear-reducing high-strength aluminum alloy composite material of the present invention includes an aluminum alloy matrix, in-situ wear-reducing phases Ti2AlN and Ti2SiN and ceramic reinforcing phase AlN, and the mass ratio of Ti2AlN, Ti2SiN to AlN is 3~5:1~2:1~2.

[0005] Furthermore, the wear-reducing phases Ti2AlN, Ti2SiN, and ceramic-strengthening phase AlN are formed by the decomposition of TiH2 powder under the action of a high-energy laser beam and the in-situ reaction of nitrogen and aluminum alloy.

[0006] The forming method of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material of the present invention includes the following steps:

[0007] (1) The aluminum alloy powder is pre-treated by rolling deformation to make its surface nano-sized, resulting in a high specific surface area.

[0008] (2) The above-mentioned surface nano-sized aluminum alloy powder and nano TiH2 powder are ball-milled and mixed to obtain a uniformly mixed aluminum alloy composite material powder.

[0009] (3) In a mixed nitrogen and argon gas environment, a high-energy laser beam is used to sweep and melt the aluminum alloy composite powder, so that the hydrogen gas decomposed from the nano TiH2 powder coats the aluminum alloy. The decomposed Ti reacts with nitrogen and aluminum-silicon alloy in situ under high temperature induced by the laser beam to form Ti2AlN, Ti2SiN anti-friction phase and AlN ceramic strengthening phase with layered lubrication function, thus obtaining an aluminum alloy composite material reinforced with in situ anti-friction phase Ti2AlN, Ti2SiN and ceramic phase AlN.

[0010] Further, in step (1), the aluminum alloy is one or more of AlSi12, AlSi20, and AlSi40, the rolling pressure is 20-80 MPa, and the rolling deformation pretreatment is carried out under inert argon gas conditions.

[0011] Furthermore, in step (2), the mass ratio of aluminum alloy powder to nano TiH2 powder is 8:1 to 20:1, and the ball milling is carried out in an inert argon atmosphere.

[0012] Furthermore, in step (3), the flow rate ratio of the nitrogen and argon mixture is 1:10 to 1:20, and the power of the laser beam is 250 to 350W.

[0013] Invention Principle: This invention addresses the mechanical performance requirements of aluminum alloys. Based on the physical properties of aluminum alloys and the excellent anti-friction function of layered nitride ceramics, and targeting the insufficient strength and wear resistance of aluminum alloys as well as the easy oxidation problem during the laser forming process, this invention, based on materials design and in-situ reaction thermodynamics, uses widely used aluminum-silicon alloy powder as the target. The aluminum alloy powder is pre-treated by rolling deformation under inert argon to increase its surface area. Then, it is ball-milled and mixed with nano-TiH2 powder under inert argon, so that the nano-TiH2 powder can be uniformly adsorbed on the surface of the aluminum alloy powder. Under the action of a nitrogen and argon mixed gas environment and a high-energy laser beam, the hydrogen gas decomposed by TiH2 powder coats the aluminum alloy, generating a reducing atmosphere, which further prevents oxidation during high-temperature forming. At the same time, the decomposed Ti reacts in situ with nitrogen and aluminum-silicon alloy under high-temperature induced by the laser beam to form Ti2AlN and Ti2SiN anti-friction phases with layered lubrication function and AlN ceramic strengthening phase to strengthen the aluminum alloy. This results in a high-strength aluminum alloy with in-situ multi-phase synergistic wear reduction, thereby improving its wear resistance and strength.

[0014] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0015] (1) By combining reactive gas phase assistance and high-temperature laser beam induction, layered Ti2AlN and Ti2SiN anti-wear phases with anti-wear function are synthesized in situ on the aluminum alloy matrix, which can effectively improve the wear resistance of the aluminum alloy. On the other hand, the AlN ceramic phase formed in situ has similar physical properties to the aluminum alloy matrix, which can significantly improve the strength of the aluminum alloy.

[0016] (2) The aluminum alloy powder is pretreated by rolling deformation to obtain high specific surface energy, which promotes the uniform adsorption of more nano TiH2 powder on its surface. Under the action of high-energy laser beam, the hydrogen gas decomposed by TiH2 powder can better coat the aluminum alloy, forming a good reducing atmosphere, effectively isolating it from contact with oxygen, thereby avoiding the formation of oxide impurities and affecting the mechanical properties of aluminum alloy. Attached Figure Description

[0017] Figure 1 The image shows the microstructure of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material prepared in Example 1, wherein the phases are 1-Ti2AlN, 2-Ti2SiN, and 3-AlN.

[0018] Figure 2 The wear rate of the in-situ multiphase synergistic composite wear-reducing high-strength aluminum alloy composite material prepared in Examples 1-4;

[0019] Figure 3 This is a comparison diagram of the tensile strength of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite materials prepared in Examples 1 to 4. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0021] Example 1

[0022] (1) AlSi10Mg aluminum alloy powder was pretreated by rolling deformation under inert argon gas with a pressure of 20MPa to make its surface nano-sized and have a high specific surface area.

[0023] (2) The high surface area aluminum alloy powder described in step 1 and nano TiH2 powder are ball-milled and mixed in an inert argon atmosphere at a mass ratio of 15:1 to obtain a uniformly mixed aluminum alloy composite material powder.

[0024] (3) In a nitrogen and argon mixed gas environment with a flow ratio of 1:20, a high-energy laser beam with a power of 250W is used to sweep and melt the composite material powder in step (2), so that the hydrogen decomposed from the nano TiH2 powder coats the aluminum alloy. The decomposed Ti reacts with nitrogen and aluminum-silicon alloy in situ under high temperature induced by the laser beam to form Ti2AlN, Ti2SiN anti-friction phase and AlN ceramic strengthening phase with layered lubrication function, and obtains aluminum alloy composite material reinforced with in situ anti-friction phase Ti2AlN, Ti2SiN and ceramic phase AlN.

[0025] from Figure 1 It can be found that the in-situ formed anti-friction phases Ti2AlN, Ti2SiN and ceramic strengthening phase AlN can be uniformly dispersed on the aluminum alloy matrix. After X-ray energy dispersive spectroscopy, no oxygen element was found. This further indicates that the method can form anti-friction phases and nitride ceramic phases. At the same time, the hydrogen gas decomposed from TiH2 powder can effectively prevent the high-temperature aluminum alloy melt from reacting with oxygen to form oxides during the forming process.

[0026] Example 2

[0027] The difference between this embodiment and embodiment 1 is that the mass ratio of aluminum alloy powder to nano TiH2 powder in step (2) is 8:1.

[0028] Example 3

[0029] The difference between this embodiment and embodiment 2 is that the rolling pressure in step (1) is 80MPa; and the power of the laser beam in step (3) is 350W.

[0030] Example 4

[0031] The difference between this embodiment and embodiment 3 is that the aluminum alloy in step (1) is AlSi11; and the flow ratio of the nitrogen and argon mixture in step (3) is 1:10.

[0032] Figure 2 The wear rates of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composites formed in Examples 1-4 range from 0.5 to 2.7 × 10⁻⁶. -5 mm 3 Within the range of / N·m, the wear rate is lower than that of existing in-situ SiC ceramic-reinforced AlSi10Mg composites (approximately 3.38 × 10⁻⁶ N·m). -5 mm 3 The wear rate of aluminum alloys is mainly attributed to the in-situ formation of layered lubricating Ti2AlN and Ti2SiN anti-wear phases, which can impart anti-wear function to aluminum alloys and thus significantly reduce the wear rate of aluminum alloys. Figure 3The tensile strength of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composites formed in Examples 1-4 is higher than 525 MPa, which is significantly higher than the tensile strength of TiN-reinforced AlSi10Mg composite (491 MPa). This is mainly attributed to the strengthening effect of multiple ceramic phases in situ, further demonstrating that this method can effectively improve the tensile strength of aluminum alloys.

[0033] Comparative Example 1

[0034] The specific preparation process is the same as in Example 1, except that in step (2), nano TiH2 powder is not used. Instead, aluminum alloy powder is directly laser-scanned and melted in a nitrogen and argon mixed environment to obtain an aluminum alloy composite material reinforced only with AlN ceramics.

[0035] The aluminum alloy composite material prepared in Comparative Example 1 only had an aluminum nitride ceramic reinforcing phase, and its wear rate was measured to be approximately 3.1 × 10⁻⁶. -5 mm 3 / N·m, which is lower than the wear reduction effect of the Ti2AlN and Ti2SiN dual lubricating phases in this method, thus demonstrating that the in-situ wear-reducing phase in the method of this invention has a significant wear reduction function.

Claims

1. An in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material, characterized in that, The structure comprises an aluminum alloy matrix, layered in-situ wear-reducing phases Ti2AlN and Ti2SiN, and a ceramic reinforcing phase AlN, with a mass ratio of Ti2AlN, Ti2SiN to AlN of 3–5:1–2:1–2. The layered in-situ wear-reducing phases Ti2AlN, Ti2SiN, and the ceramic reinforcing phase AlN are formed through the decomposition of TiH2 powder under high-energy laser beam irradiation and the in-situ reaction of nitrogen and aluminum alloy. The aluminum alloy is AlSiN. 10 Mg, AlSi 12 or AlSi 20 One or more of them.

2. A forming method for the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material as described in claim 1, characterized in that, Includes the following steps: (1) The aluminum alloy powder is pretreated by rolling deformation to make its surface nano-sized; (2) The above-mentioned surface-nanosized aluminum alloy powder and nano-TiH2 powder were ball-milled and mixed to obtain a uniformly mixed aluminum alloy composite material powder. (3) In a mixed nitrogen and argon gas environment, a high-energy laser beam is used to sweep and melt the aluminum alloy composite powder, so that the hydrogen gas decomposed from the nano TiH2 powder coats the aluminum alloy. The decomposed Ti reacts with nitrogen and aluminum-silicon alloy in situ under high temperature induced by the laser beam to form Ti2AlN, Ti2SiN anti-friction phase and AlN ceramic strengthening phase with layered lubrication function, thus obtaining an aluminum alloy composite material reinforced with in situ anti-friction phase Ti2AlN, Ti2SiN and ceramic phase AlN.

3. The forming method of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material according to claim 2, characterized in that, The rolling pressure in step (1) is 20-80 MPa.

4. The forming method of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material according to claim 2, characterized in that, The rolling deformation pretreatment in step (1) is carried out under inert argon gas conditions.

5. The forming method of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material according to claim 2, characterized in that, In step (2), the mass ratio of aluminum alloy powder to nano TiH2 powder is 8:1 to 20:

1.

6. The forming method of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material according to claim 2, characterized in that, In step (2), the ball milling and mixing are carried out in an inert argon atmosphere.

7. The forming method of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material according to claim 2, characterized in that, In step (3), the flow rate ratio of the nitrogen and argon mixture is 1:10 to 1:

20.

8. The forming method of the in-situ multiphase synergistic composite friction-reducing high-strength aluminum alloy composite material according to claim 2, characterized in that, The power of the laser beam in step (3) is 250-350W.

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