Wide-temperature-range low-expansion constant-elasticity aluminum-based composite material and preparation method thereof

Abstract

A wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material and its preparation method, belonging to the field of metal matrix composites, includes: using high-purity aluminum powder as the matrix, FeNi... 36 Invar alloy particles are used as a modulus-regulating reinforcing phase, and the two are uniformly dispersed and mixed using an acoustic resonance mixing process. The mixed composite powder is then sintered by spark plasma to prepare a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material. This invention relies on FeNi 36 Due to the unique anomalous evolution of the elastic modulus of Invar alloys, this invention effectively counteracts the continuous decline in the matrix modulus with increasing temperature and the increase in the coefficient of thermal expansion with increasing temperature through a reverse compensation mechanism of its elastic modulus change with temperature, achieving a constant elastic effect over a wide temperature range. This invention ensures a strong and clean metallurgical bond at the two-phase interface, guaranteeing the composite material possesses excellent thermal stability, good tensile strength, and good plastic deformation capacity.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composite technology, specifically relating to a wide-temperature-range low-expansion constant-elasticity aluminum matrix composite material and its preparation method. Background Technology

[0002] With the miniaturization, high integration, and high power density of electronic devices, and the increasing demands on the service stability of precision machinery and aerospace optical instruments, structural materials need to simultaneously meet the following stringent requirements: an extremely low coefficient of thermal expansion (CTE) to achieve compatibility with semiconductor chips (~2.6×10⁻⁶). -6 K -1 ) and ceramic substrate (~7×10 -6 K -1 It has excellent thermal matching; constant elastic modulus over a wide temperature range; and excellent thermal conductivity and good plastic processing ability.

[0003] Although pure aluminum and commonly used aluminum alloys have good thermal conductivity and machinability, their coefficient of thermal expansion is relatively high (approximately 23–24 × 10⁻⁶ at room temperature). -6 K -1 This results in a severe mechanical and thermal mismatch between the aluminum substrate and silicon chips and ceramic substrates. Furthermore, the elastic modulus of the aluminum substrate fluctuates drastically with temperature, making it difficult to meet the dimensional stability requirements of high-precision service environments.

[0004] To address the aforementioned issues, existing technologies typically employ ceramic particles such as SiC and Al2O3 as reinforcing phases to prepare aluminum-based composites in order to reduce the coefficient of thermal expansion. However, such composites suffer from significant technical drawbacks: due to the poor wettability between the ceramic reinforcing phase and the aluminum matrix, a brittle reaction layer is easily formed at the interface, leading to severe deterioration of the material's plasticity, with an elongation at break generally below 5%; simultaneously, ceramic particles are unable to provide temperature compensation for the elastic modulus, failing to achieve constant elasticity over a wide temperature range.

[0005] FeNi 36 Invar alloys exhibit a typical Invar effect, with an extremely low coefficient of linear expansion near room temperature (below 1×10⁻⁶). -6 K -1 It also possesses excellent metallic ductility. Theoretically, FeNi... 36 Invar alloys, used as reinforcing phases in aluminum-based composites, effectively achieve a synergistic effect of low expansion, high thermal conductivity, and high plasticity. However, existing manufacturing processes (such as casting, pressureless sintering, and conventional hot pressing) face significant technical bottlenecks: during high-temperature sintering, the aluminum matrix readily undergoes vigorous interfacial diffusion reactions with Fe and Ni elements, generating brittle intermetallic compounds such as Al3Fe and Al3Ni. These brittle phases not only weaken the material's plasticity and thermal conductivity but also damage the FeNi... 36The microstructure of Invar alloys is unstable, thus losing the Invar effect. In addition, the excessively high sintering temperature and excessively long holding time of traditional processes also make it difficult for materials to achieve the synergistic effect of low expansion and constant elasticity over a wide temperature range.

[0006] In summary, a FeNi alloy was developed that enables controllable interfacial reactions and exhibits both constant elasticity over a wide temperature range and low expansion properties. 36 Developing aluminum-based composite materials and exploring efficient preparation methods to match them are key technical issues that urgently need to be addressed in the field of metal matrix composites. Summary of the Invention

[0007] The present invention aims to provide a wide-temperature-range low-expansion constant elastic aluminum matrix composite material and its preparation method, in order to solve the technical problems of high temperature sensitivity of elastic modulus of existing metal matrix composite materials in wide-temperature-range service environments, and the excessive density of traditional constant elastic alloys, which cannot meet the requirements of lightweighting.

[0008] The technical solution adopted by this invention to solve the technical problem is as follows: The present invention provides a method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material, which mainly includes the following steps: Step S1: Select high-purity aluminum powder as the matrix, FeNi 36 Invar alloy particles are used as modulus-regulating reinforcing phases, combining high-purity aluminum powder with FeNi 36 Invar alloy particles are uniformly dispersed and mixed using an acoustic resonance mixing process; Step S2: The mixed composite powder is sintered by spark plasma to prepare a wide-temperature-range low-expansion constant-elasticity aluminum-based composite material.

[0009] In a preferred embodiment, the purity of the high-purity aluminum powder is ≥99.99%, and the particle size of the high-purity aluminum powder is 15μm~53μm.

[0010] As a preferred embodiment, the FeNi 36 The particle size of Invar alloy particles ranges from 15μm to 53μm.

[0011] As a preferred embodiment, the FeNi 36 The volume percentage of Invar alloy particles in the wide-temperature-range low-expansion constant-elasticity aluminum matrix composite material is 40% to 60%.

[0012] As a preferred embodiment, the parameters of the acoustic resonance mixing process are: resonance acceleration of 30g to 80g, vibration frequency of 40Hz to 80Hz, mixing in multiple cycles, and a single mixing time of 200s to 300s.

[0013] In a preferred embodiment, during multiple cycles of mixing, the interval between two adjacent mixing operations is 3 to 5 minutes of rest.

[0014] As a preferred embodiment, the parameters of the spark plasma sintering are: sintering temperature 500℃~600℃, axial forming pressure 30MPa~50MPa, and holding time 5min~15min.

[0015] In a preferred embodiment, the cavity vacuum level is maintained at ≤10 throughout the entire process of the spark plasma sintering. -3 Pa.

[0016] The present invention also provides a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material with an elastic modulus ratio of 0.99 to 1.00; and a coefficient of thermal expansion of 10.1990 × 10⁻⁶ within a temperature range of 0 to 140°C. -6 K -1 .

[0017] The beneficial effects of this invention are: 1. This invention relies on FeNi 36 Due to the anomalous evolution of the elastic modulus unique to Invar alloys, its reverse compensation mechanism of elastic modulus change with temperature effectively counteracts the continuous decline trend of the matrix elastic modulus with increasing temperature and the increase of the coefficient of thermal expansion with increasing temperature. Experiments have shown that the wide-temperature-range low-expansion constant-elasticity aluminum-based composite material prepared by this invention maintains a relative change rate of elastic modulus within 1% in a wide service temperature range of room temperature to 150℃, achieving a constant elasticity effect over a wide temperature range and significantly improving the service environment adaptability of high-precision components.

[0018] 2. This invention, through precise control of the kinetic parameters (such as heating rate, sintering pressure, and holding time) throughout the entire spark plasma sintering process, effectively suppresses the intense interdiffusion reaction between the matrix and the modulus-controlled reinforcing phase interface while ensuring densification. This significantly reduces the precipitation and agglomeration of brittle intermetallic compounds (such as Al3Fe and Al3Ni) at the interface, ensuring a strong and clean metallurgical bond between the two phases. This optimization method ensures that the composite material possesses excellent thermal stability while also exhibiting good tensile strength and plastic deformation capacity.

[0019] 3. This invention breaks through the limitation of the traditional composite material matrix being singular. The matrix material selection has high compatibility and can be adapted to pure aluminum or a variety of commercial aluminum alloys. At the same time, by flexibly adjusting the modulus to control the volume fraction of the reinforcing phase, it can achieve targeted design and precise control of material performance indicators for the specific load-bearing load, service temperature and modulus requirements of components in various scenarios such as spacecraft, inertial navigation and precision optical systems.

[0020] 4. The high-purity aluminum powder and FeNi used in this invention 36 Invar alloy particles are all commercially available, mature raw materials, requiring no special customization, effectively reducing raw material acquisition costs. The entire preparation method is simple and controllable, with extremely high process stability and repeatability. Furthermore, the spark plasma sintering technology is characterized by high efficiency and near-net-shape forming, which can meet the needs of large-scale continuous production, possessing significant industrialization value and market competitive advantages. Attached Figure Description

[0021] Figure 1 This is a scanning electron microscope image of the wide-temperature-range low-expansion constant-elasticity aluminum-based composite material prepared in Example 1.

[0022] Figure 2 The image is a scanning electron microscope image of the composite material prepared in Comparative Example 1.

[0023] Figure 3 The elastic modulus-temperature curves are for the composite materials prepared in Example 1 and Comparative Example 1.

[0024] Figure 4 The thermal expansion properties of the wide-temperature-range low-expansion constant elastic aluminum matrix composite material prepared in Example 1 are shown in the figure.

[0025] Figure 5 The images show the XRD patterns of the composite materials prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0026] In a first aspect, the present invention provides a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material.

[0027] This invention provides a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material with an elastic modulus ratio of 0.99–1.00; and a coefficient of thermal expansion of 10.1990 × 10⁻⁶ within a temperature range of 0–140°C. -6 K -1 .

[0028] This invention provides a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material, using high-purity aluminum powder as the composite matrix, and incorporating FeNi... 36 Invar alloy particles were used as modulus-regulating reinforcing phases to construct an aluminum-based composite system based on finely controlled interfacial microstructure. The core mechanism lies in: utilizing FeNi... 36The anomalous evolution of the elastic modulus and low expansion characteristics inherent in Invar alloy particles within a specific service temperature range, combined with the linear decay of the matrix elastic modulus with increasing temperature, create a counter-compensating synergistic effect. This effectively counteracts the decay of the matrix elastic modulus with increasing temperature and the increase in the coefficient of thermal expansion, achieving constant elastic modulus and low expansion characteristics of the composite material over a wide temperature range. Furthermore, by precisely controlling the distribution of the reinforcing phase and the bonding strength at the matrix / reinforcing phase interface, this invention suppresses fluctuations in the overall elastic modulus of the composite material on a macroscopic scale, achieving constant elastic modulus over a wide temperature range.

[0029] Secondly, the present invention provides a method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material.

[0030] The present invention provides a method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material, the specific implementation process of which is as follows: (1) High-purity aluminum powder with a purity of ≥99.99% and a particle size of 15μm~53μm was selected as the matrix of the composite material; (2) Select FeNi with a particle size of 15μm to 53μm. 36 Invar alloy particles serve as modulus-regulating reinforcing phases, FeNi 36 The volume percentage of Invar alloy particles in low-expansion constant-elasticity aluminum matrix composites over a wide temperature range is 40% to 60%.

[0031] Preferably, FeNi 36 Invar alloy particles account for 50% of the volume of the low-expansion constant-elasticity aluminum matrix composite material in a wide temperature range.

[0032] (3) Acoustic resonance mixing process; High-purity aluminum powder and FeNi 36 Invar alloy particles are uniformly dispersed and mixed using an acoustic resonance mixing process to obtain a homogeneous composite powder. The parameters of the acoustic resonance mixing process are: resonance acceleration of 30g to 80g, vibration frequency of 40Hz to 80Hz, multiple cycles of mixing, single mixing time of 200s to 300s, and a standing interval of 3min to 5min between two adjacent mixing operations.

[0033] (4) Spark Plasma Sintering (SPS); The homogenized composite powder was filled into a graphite sintering mold, and a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material was prepared by spark plasma sintering. The parameters for spark plasma sintering were: sintering temperature 500℃~600℃, axial forming pressure 30MPa~50MPa, holding time 5min~15min, and maintaining a cavity vacuum degree ≤10 throughout the sintering process. -3Pa. After spark plasma sintering, the spark plasma sintering material is uniformly dispersed within the matrix.

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1 This embodiment provides a method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material, the specific operation steps of which are as follows: (1) High-purity aluminum powder with a purity of ≥99.99% and a particle size of 50μm was selected as the matrix of the composite material; (2) Select FeNi with a particle size of 35μm 36 Invar alloy particles serve as modulus-regulating reinforcing phases, FeNi 36 Invar alloy particles account for 50% of the volume of the low-expansion constant-elasticity aluminum matrix composite material in a wide temperature range.

[0036] (3) Mix high-purity aluminum powder with FeNi 36 Invar alloy particles are uniformly dispersed and mixed using an acoustic resonance mixing process to obtain a homogeneous composite powder. The parameters of the acoustic resonance mixing process are: resonance acceleration of 80g, vibration frequency of 60Hz, mixing in 3 cycles, each mixing cycle lasting 300s, and a 2-minute interval between two adjacent mixing operations.

[0037] (4) The mixed composite powder was filled into a graphite sintering mold, and a wide-temperature-range low-expansion constant-elasticity aluminum-based composite material was prepared by spark plasma sintering (SPS). The parameters of spark plasma sintering were: sintering temperature 520℃, axial forming pressure 40MPa, holding time 10min, and the vacuum degree of the cavity was maintained at 10 throughout the sintering process. -3 Pa.

[0038] Comparative Example 1 This comparative example provides a method for preparing an aluminum-based composite material. The specific operation steps are carried out according to Example 1, except that in this comparative example, FeNi... 36 The volume percentage of Invar alloy particles in aluminum matrix composites is 10%.

[0039] Experimental Example 1 Scanning electron microscopy (SEM) was used to image the composite materials prepared in Example 1 and Comparative Example 1. The SEM image of the wide-temperature-range low-expansion constant-elasticity aluminum-based composite material prepared in Example 1 is shown below. Figure 1 As shown, the scanning electron microscope image of the composite material prepared in Comparative Example 1 is as follows. Figure 2 As shown in the figure, the comparison reveals that the microstructure of the wide-temperature-range low-expansion constant-elasticity aluminum-based composite material prepared by this invention is relatively uniform, wherein FeNi 36 Because the alloy particles are dispersed and no obvious defects such as interface debonding were observed, it indicates that the preparation method used in this invention effectively promotes a good bond between the composite matrix and the modulus-controlled reinforcing phase.

[0040] Experimental Example 2 The composite materials prepared in Example 1 and Comparative Example 1 were characterized for comprehensive mechanical properties. The test results are as follows: Figure 3 As shown, the elastic modulus ratio E of the composite material prepared in Comparative Example 1 is [value missing] within a wide temperature range of service from room temperature to 150°C. T / E0(E T (where E is the modulus at temperature T and E0 is the room temperature modulus) exhibits a certain decreasing trend with increasing temperature. The mechanism is believed to be due to the fact that FeNi... 36 The relatively low volume fraction of Invar alloy particles in the composite material results in insufficient anomalous contribution to the elastic modulus based on the Invar effect, failing to completely offset the intrinsic modulus softening effect of high-purity aluminum powder with increasing temperature. Within a wide temperature range of room temperature to 150°C, the elastic modulus ratio E of the wide-temperature-range low-expansion constant-elasticity aluminum-based composite material prepared in Example 1 is [not specified]. T The elastic modulus / E0 remained stable between 0.99 and 1.00, with the relative change rate controlled within 1%, demonstrating excellent stability and superior constant elasticity. These test results indicate that by increasing the FeNi... 36 The volume ratio of Invar alloy particles in wide-temperature-range low-expansion constant-elasticity aluminum matrix composites can improve the constant elasticity effect of wide-temperature-range low-expansion constant-elasticity aluminum matrix composites over a wide temperature range.

[0041] Experimental Example 3 The thermal expansion properties of the wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material prepared in Example 1 were characterized. The test results are as follows: Figure 4 As shown, within the temperature range of 0–140°C, the coefficient of thermal expansion (CTE) of the wide-temperature-range low-expansion constant-elasticity aluminum matrix composite material prepared in Example 1 is 10.1990 × 10⁻⁶. -6 K -1 Compared to pure aluminum, it shows a significant reduction, indicating that FeNi 36 Invar alloy particles can effectively suppress the thermal expansion behavior of high-purity aluminum powder.

[0042] Test Example 4 The microstructure of the composite materials prepared in Example 1 and Comparative Example 1 was examined using XRD phase analysis. The test results are as follows: Figure 5 As shown, no characteristic diffraction peaks of brittle intermetallic compounds such as Al3Fe and Al3Ni were detected in the XRD diffraction peaks of the composite material. This indicates that the preparation method used in this invention effectively suppresses the reaction between high-purity aluminum powder and FeNi through precise kinetic control. 36 The interfacial interdiffusion reaction of Invar alloy particles during high-temperature sintering achieves a clean and robust metallurgical bond between the two phases, ensuring the chemical stability of the interfacial structure and laying a solid microstructural foundation for improving the macroscopic mechanical properties of composite materials.

[0043] This invention discloses a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material and its preparation method. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the same result. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The product of this invention has been described through preferred embodiments, and those skilled in the art can clearly make modifications or appropriate alterations and combinations to the product without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

Claims

1. A method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material, characterized in that, Includes the following steps: Step S1: Select high-purity aluminum powder as the matrix, FeNi 36 Invar alloy particles are used as modulus-regulating reinforcing phases, combining high-purity aluminum powder with FeNi 36 Invar alloy particles are uniformly dispersed and mixed using an acoustic resonance mixing process; Step S2: The mixed composite powder is sintered by spark plasma to prepare a wide-temperature-range low-expansion constant-elasticity aluminum-based composite material.

2. The method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material according to claim 1, characterized in that, The purity of the high-purity aluminum powder is ≥99.99%, and the particle size of the high-purity aluminum powder is 15μm~53μm.

3. The method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material according to claim 1, characterized in that, The FeNi 36 The particle size of Invar alloy particles ranges from 15μm to 53μm.

4. The method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material according to claim 1, characterized in that, The FeNi 36 The volume percentage of Invar alloy particles in the wide-temperature-range low-expansion constant-elasticity aluminum matrix composite material is 40% to 60%.

5. The method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material according to claim 1, characterized in that, The parameters of the acoustic resonance mixing process are: resonance acceleration of 30g to 80g, vibration frequency of 40Hz to 80Hz, mixing in multiple cycles, and a single mixing time of 200s to 300s.

6. The method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material according to claim 5, characterized in that, During multiple mixing cycles, allow the material to stand for 3 to 5 minutes between each adjacent mixing operation.

7. The method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material according to claim 1, characterized in that, The parameters for the spark plasma sintering are: sintering temperature 500℃~600℃, axial forming pressure 30MPa~50MPa, and holding time 5min~15min.

8. The method for preparing a wide-temperature-range, low-expansion, constant-elasticity aluminum-based composite material according to claim 1, characterized in that, The vacuum level of the cavity is maintained at ≤10 throughout the entire process of spark plasma sintering. -3 Pa.

9. A wide-temperature-range low-expansion constant-elasticity aluminum-based composite material prepared by the method for preparing a wide-temperature-range low-expansion constant-elasticity aluminum-based composite material according to any one of claims 1-8, characterized in that, The elastic modulus ratio of this composite material is 0.99–1.00; its coefficient of thermal expansion is 10.1990 × 10⁻⁶ within a temperature range of 0–140 °C. - 6 K -1 .

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