A high-toughness multi-scale hierarchical structure aluminum matrix composite material and a powder metallurgy preparation method thereof

Abstract

This invention belongs to the field of powder metallurgy technology, and relates to a high-strength and tough multi-scale hierarchical aluminum-based composite material and its powder metallurgy preparation method. The composite material uses aluminum powder, silicon powder, titanium powder, and TiO2 as raw materials. Through a combination of low-temperature powder metallurgy preparation and heat treatment, a multi-scale hierarchical microstructure is generated in situ using solid-state diffusion reactions between the components to produce micron-nano Ti5Si3 particles at grain boundaries and nano-Al2O3 particles within the grains. The preparation method includes: weighing raw materials, graded ball milling and mixing, assembling, degassing and sealing, hot isostatic pressing densification, heat treatment, and machining. This invention achieves stable synthesis of Ti5Si3 and Al2O3 particles through solid-state powder metallurgy; the load-bearing effect of micron-sized Ti5Si3 at grain boundaries and the enhancement of dislocation multiplication and storage capacity by nano-sized Ti5Si3 at grain boundaries and nano-Al2O3 within the grains hinder grain boundary migration and dislocation movement under room temperature / high temperature conditions, synergistically improving the room temperature strength, toughness, and high-temperature performance of the composite material.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy technology, specifically relating to a high-strength and tough multi-scale hierarchical aluminum-based composite material and its powder metallurgy preparation method. Background Technology

[0002] Titanium-reinforced aluminum matrix composites, due to their simple composition, high designability, and outstanding strengthening effect, have broad application prospects in key equipment fields under the requirements of lightweighting and high performance. Based on the design of Al-Si-Ti composite systems, domestic and foreign researchers have developed aluminum matrix composites through in-situ composite processes such as molten salt method, casting method, and semi-solid thixotropic forming. In these composites, titanium can react with the aluminum-silicon matrix to generate ternary intermetallic compounds such as Ti(Al, Si)3. The high growth limiting factor of titanium demonstrates potential advantages in refining the matrix structure and improving matrix strength.

[0003] However, this composite material system currently faces several key problems: (1) the reaction products generated under traditional high-temperature preparation conditions (such as Ti(Al, Si)3, Ti7Al5Si) 12 (1) Ternary intermetallic compounds such as Ti(Si, Al)2 are unstable and easily undergo phase transformations, making it difficult to control the in-situ reaction process and the reinforcement phase is complex, making it difficult to effectively regulate the microstructure and properties; (2) Ternary intermetallic compounds are incompatible with the matrix interface, and during loading, they are prone to cause interface stress concentration due to deformation incoordination, which can induce microcracks. In particular, as the service temperature increases, the softening of the matrix further exacerbates the deformation incoordination with the reinforcement phase; (3) The reaction between titanium and aluminum-silicon matrix depends on the interdiffusion process of elements. Therefore, the particle size of the in-situ reaction reinforcement phase is controlled by the particle size of the raw material powder. The single-size particle has limited strengthening efficiency and insufficient ability to simultaneously hinder grain boundary migration and dislocation movement through pinning effect, resulting in limited strengthening effect and insufficient high-temperature performance of composite materials; (4) Traditional high-temperature preparation process easily causes coarsening of eutectic silicon particles, which leads to a decrease in the plasticity of composite materials. Therefore, controlling the reaction process of the system to achieve stable synthesis of the reinforcing phase; regulating the size and distribution characteristics of the reinforcing phase to improve the interfacial matching between the matrix and the reinforcing phase; promoting the load-bearing effect of the in-situ reinforcing phase particles while reducing interfacial stress concentration; and enhancing the hindrance effect on matrix grain boundary migration and dislocation movement under room temperature and high temperature conditions are crucial to improving the strength and toughness matching and high temperature mechanical properties of the composite material system.

[0004] In view of this, the present invention proposes a high-strength and tough multi-scale hierarchical aluminum matrix composite material and a powder metallurgy preparation method. By designing a multi-scale hierarchical structure of the in-situ reinforcing phase in the aluminum matrix composite material, the invention aims to overcome the defects of the prior art and meet the engineering requirements of the aerospace and automotive fields for aluminum matrix composite materials with synergistic matching of high strength, toughness and heat resistance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and propose a high-strength and tough multi-scale hierarchical aluminum matrix composite material and a powder metallurgy preparation method. This invention achieves stable synthesis of the reinforcing phase by controlling the reaction process of the composite material system; regulates the size and distribution characteristics of the reinforcing phase, improves the interface matching between the matrix and the reinforcing phase, promotes the load-bearing effect of the in-situ reinforcing phase particles while reducing interface stress concentration, and enhances the hindering effect on matrix grain boundary migration and dislocation movement under room temperature and high temperature conditions, thereby improving the strength and toughness matching and high-temperature mechanical properties of the composite material system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a high-strength and tough multi-scale hierarchical aluminum-based composite material, which can achieve a synergistic improvement in room temperature toughness and high temperature performance through the synergistic effect of grain boundary micron-nano Ti5Si3 particles and intracrystalline nano Al2O3 particles.

[0007] This invention provides a high-strength and tough multi-scale hierarchical aluminum-based composite material, comprising a matrix phase and a reinforcing phase. The matrix phase is an aluminum matrix, and the reinforcing phase includes eutectic silicon particles distributed in the aluminum matrix, micron- and nano-sized Ti5Si3 particles generated in situ at grain boundaries, and intracrystalline nano-Al2O3 particles. The in-situ generated reinforcing phase constitutes a multi-scale hierarchical microstructure. The ratio of the aluminum matrix, the micron- and nano-sized Ti5Si3 particles at grain boundaries, and the intracrystalline nano-Al2O3 particles can be controlled by the raw material ratio.

[0008] Furthermore, the aluminum-based composite material is composed of the following raw material components by mass percentage: 83~98.8 wt.% aluminum powder, 1~12 wt.% silicon powder, 0.1~3 wt.% titanium powder, and 0.1~2 wt.% TiO2 powder.

[0009] Furthermore, the aluminum powder has a particle size of 20-30 μm; the silicon powder has a particle size of 1-5 μm; the titanium powder has a particle size of 1-10 μm; and the TiO2 powder has a particle size of 20-100 nm.

[0010] Preferably, the silicon powder, titanium powder, and TiO2 powder are all irregularly shaped.

[0011] See Figure 1Secondly, this invention provides a method for preparing a high-strength and high-toughness multi-scale hierarchical aluminum-based composite material. By combining powder metallurgy low-temperature preparation process and heat treatment process, the solid-phase diffusion reaction between Ti-Si and Al-Si-TiO2 components is promoted while the formation of Al-Si-Ti ternary intermetallic compounds is inhibited. This solves the problem that the in-situ reaction products are unstable, resulting in poor compatibility with the matrix interface, which leads to the inversion of strength and toughness and insufficient high-temperature stability. It also solves the problem that traditional high-temperature preparation conditions easily cause coarsening of eutectic silicon particles, which leads to a decrease in the plasticity of the composite material.

[0012] The present invention provides a method for preparing a high-strength and tough multi-scale hierarchical aluminum-based composite material, which is used to prepare the aluminum-based composite material described in the first aspect, comprising the following steps: Step 1: Weigh the raw materials according to the proportion of raw material components set in the first aspect, then ball mill and mix silicon powder, titanium powder and TiO2 powder under an inert atmosphere, and then add aluminum powder and continue ball milling and mixing to obtain a mixed powder; Step 2: The mixed powder obtained in Step 1 is loaded into a sleeve and degassed and sealed. Then, it is subjected to hot isostatic pressing and cooled to obtain the composite material blank. Step 3: The composite material blank obtained in Step 2 is heat-treated, and then the cladding is removed by machining to obtain an aluminum-based composite material with a multi-scale hierarchical structure.

[0013] Further, in step one, silicon powder, titanium powder, and TiO2 powder are mixed using a planetary ball mill under an inert atmosphere of argon, with a ball-to-powder ratio of 1~5:1, a milling speed of 100~200 r / min, and a time of 2~6 h. Then, aluminum powder is added and mixed again using a planetary ball mill or a drum ball mill, with a ball-to-powder ratio of 5~10:1, a milling speed of 200~300 r / min, and a time of 4~8 h, under an inert atmosphere of argon.

[0014] Furthermore, in step two, when the vacuum degree is <1×10 -3 The mixed powder is loaded into a package under Pa conditions, and then degassed by vibration at a temperature of 100~300℃ for 2~6 hours.

[0015] Furthermore, in step two, the hot isostatic pressing process includes a medium-temperature high-pressure stage and a high-temperature high-pressure stage. The parameters for the medium-temperature high-pressure stage are: temperature 450~520℃, pressure 150~180MPa, and holding time 1~4h. After the holding time is completed, the temperature is raised to the high-temperature high-pressure stage while maintaining the pressure. The parameters for the high-temperature high-pressure stage are: temperature 520~570℃, pressure 150~180MPa, and holding time 0.5~2h.

[0016] Specifically, the heating rate of both the medium-temperature high-pressure stage and the high-temperature high-pressure stage is 3~8℃ / min.

[0017] Specifically, by setting up a two-stage hot isostatic pressing process with medium-temperature high pressure and high-temperature high pressure, the medium-temperature high pressure stage can promote the full densification of the mixed powder while avoiding the coarsening of the matrix grains, thus achieving the controllable preservation of fine-grained structure. The short-time high-temperature high pressure stage can promote the rapid metallurgical bonding of the mixed powder, which is conducive to the interdiffusion reaction process between Ti-Si and Al-Si-TiO2, promotes the formation of micron and nano Ti5Si3 at the grain boundaries, and allows oxygen atoms to diffuse into the grains through the gaps in the matrix to generate nano Al2O3 particles. This inhibits the diffusion of aluminum atoms into Ti5Si3 caused by long-term high-temperature holding, and avoids the formation of ternary intermetallic compounds such as Ti(Al, Si)3, thus laying the microstructural foundation for the synergistic optimization of the mechanical properties of composite materials.

[0018] Furthermore, in step three, the heat treatment process includes solution treatment and aging treatment, with the following parameters: (510~530)℃×(2~4)h / water cooling + (120~140)℃×(12~18)h / air cooling.

[0019] Specifically, solution treatment combined with aging heat treatment can eliminate the sharp edges of eutectic silicon particles through a high-temperature solution process, thereby passivating their microstructure. At the same time, precipitation during the aging process promotes the uniform dispersion of silicon particles.

[0020] Furthermore, the aluminum-based composite material has a tensile strength > 400 MPa, a yield strength > 300 MPa, and an elongation > 4% at room temperature; and a tensile strength > 150 MPa, a yield strength > 100 MPa, and an elongation > 10% at 300°C.

[0021] Thirdly, the present invention also provides a high-strength, high-toughness, multi-scale hierarchical aluminum-based composite material part, which is obtained by processing the aluminum-based composite material of the first aspect or the aluminum-based composite material prepared by the method of the second aspect. The performance of the part meets the requirements of the aerospace and automotive fields.

[0022] Furthermore, the aluminum-based composite material part has a tensile strength > 400 MPa, a yield strength > 300 MPa, and an elongation > 4% at room temperature; and a tensile strength > 150 MPa, a yield strength > 100 MPa, and an elongation > 10% at 300℃.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. Addressing the challenge of instability in the in-situ reaction products of this composite system, leading to poor interfacial compatibility with the matrix and consequently inverted strength and toughness, as well as insufficient high-temperature stability, this invention innovatively proposes the simultaneous introduction of micron-sized titanium and nano-sized TiO2 dual-scale titanium sources into an aluminum-silicon matrix. Through component design, the dissolution and segregation of Si, with its high solid solubility and high diffusion rate, in aluminum is utilized in the Ti5Si3 formation phase region. Using micron-sized titanium particles as templates, and employing the low-temperature powder metallurgy preparation process of this invention, the solid-liquid interdiffusion reaction between Ti-Si components is utilized to stably generate micron-sized Ti5Si3 particles at the grain boundaries while effectively suppressing unstable ternary intermetallic compounds (such as Ti(Al, Si)3 and Ti7Al5Si) in the traditional Al-Si-Ti system. 12 The formation of Ti(Si,Al)2 and other components enables the stable and controllable synthesis of the reinforcing phase. Simultaneously, by utilizing the solid-state reaction between Al-Si-TiO2 components and based on the interstitial diffusion of oxygen in the matrix, the formation of grain boundary nano-Ti5Si3 and intracrystalline nano-Al2O3 particles is promoted. This allows for the in-situ construction of a multi-scale hierarchical structure of grain boundary micron-nano Ti5Si3 particles and intracrystalline nano-Al2O3 particles in the matrix to synergistically strengthen aluminum-based composite materials.

[0024] 2. This invention constructs micron-nano dual-scale Ti5Si3 particles at grain boundaries and generates nano-Al2O3 particles within the grains, forming a multi-scale hierarchical structure of "grain boundary micron / nano Ti5Si3 + intragranular nano-Al2O3". This structure utilizes the pinning effect of grain boundary micron Ti5Si3 particles to hinder grain boundary migration, while grain boundary nano-Ti5Si3 and intragranular nano-Al2O3 particles promote dislocation multiplication and storage, hindering grain boundary migration and dislocation movement under room temperature / high temperature conditions. This enhances the matrix's sustained strain hardening capability and high-temperature softening resistance, synergistically improving the composite material's room temperature strength, toughness, and high-temperature performance. Simultaneously, the in-situ generated micron / nano Ti5Si3 particles form a semi-coherent matching relationship with the aluminum matrix, promoting interfacial compatibility, improving deformation coordination and the load-bearing capacity of micron particles, reducing interfacial stress concentration during loading, and avoiding microcracks caused by deformation incoordination. This improves the strength-toughness matching of the composite material, especially exhibiting excellent performance under medium- and high-temperature service conditions.

[0025] 3. Based on this, the size of eutectic silicon particles was effectively refined and their sharp edges were blunted through solution treatment and aging heat treatment processes, which reduced the stress concentration at irregular edges and corners, and synergistically improved the plasticity and toughness of the composite material.

[0026] 4. Based on the above optimized design, the aluminum-based composite material prepared by this invention has a tensile strength > 400 MPa, yield strength > 300 MPa, and elongation > 4% at room temperature; and a tensile strength > 150 MPa, yield strength > 100 MPa, and elongation > 10% at a high temperature of 300℃. This achieves a simultaneous improvement in room temperature toughness and high temperature strength, and significantly overcomes the defects of inverted strength and toughness and insufficient high temperature performance of traditional aluminum-based composite materials.

[0027] 5. This invention employs a powder metallurgy hot isostatic pressing process, utilizing a two-stage densification process of medium-temperature high pressure and short-time high-temperature high pressure. This ensures sufficient material densification while effectively avoiding grain coarsening and the formation of undesirable phases. The overall process parameters are controllable and highly repeatable. Furthermore, the use of aluminum as the cladding material facilitates subsequent machining removal, making it suitable for fabricating complex-shaped parts. This fully meets the engineering application needs of high-performance aluminum-based composite materials in aerospace, automotive, and other fields. Attached Figure Description

[0028] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0030] Figure 1 This is a flowchart of the preparation method of the high-strength and tough multi-scale hierarchical aluminum matrix composite material of the present invention; Figure 2 This is a scanning electron microscope image of the Al-Si-Ti-TiO2 mixed powder prepared in Example 3; Figure 3 The X-ray diffraction patterns of the composite materials prepared in Examples 1 and 2 are shown. Figure 4 Scanned image of the composite material prepared in Example 1; Figure 5 Transmission photograph of the composite material prepared in Example 2; Figure 6 To and Figure 5 The corresponding energy spectrum scan of titanium; Figure 7 To and Figure 5 The corresponding silicon element energy spectrum scan; Figure 8 To and Figure 5 The corresponding oxygen element energy spectrum scan; Figure 9High-resolution transmission image of the composite material prepared in Example 3; Figure 10 This is the room temperature tensile fracture profile of the composite material prepared in Example 3; Figure 11 This is a high-temperature tensile fracture profile of the composite material prepared in Example 3. Detailed Implementation

[0031] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0032] Example 1 In a first aspect, this embodiment provides a high-strength and tough multi-scale hierarchical aluminum-based composite material, which includes a matrix phase and a reinforcing phase; the matrix phase is an aluminum matrix, and the reinforcing phase includes eutectic silicon particles distributed in the aluminum matrix, micron and nano Ti5Si3 particles generated in situ at the grain boundaries, and intracrystalline nano Al2O3 particles.

[0033] Furthermore, the aluminum-based composite material is composed of the following raw material components by mass percentage: 85.9 wt.% aluminum powder, 12 wt.% silicon powder, 0.1 wt.% titanium powder, and 2 wt.% TiO2 powder.

[0034] The aluminum powder has a particle size of 20 μm; the silicon powder has a particle size of 1 μm and is irregularly shaped; the titanium powder has a particle size of 1 μm and is irregularly shaped; and the TiO2 powder has a particle size of 20 nm and is irregularly shaped.

[0035] Secondly, this embodiment provides a method for preparing a high-strength and tough multi-scale hierarchical aluminum-based composite material, comprising the following steps: Step 1: Weigh the following raw materials by mass percentage: 85.9 wt.% aluminum powder with a particle size of 20 μm, 12 wt.% silicon powder with a particle size of 1 μm, 0.1 wt.% titanium powder with a particle size of 1 μm, and 2 wt.% TiO2 powder with a particle size of 20 nm.

[0036] Step 2: The silicon powder, titanium powder, and TiO2 powder weighed in Step 1 are mixed in an argon atmosphere using a planetary ball mill with a ball-to-powder ratio of 1:1, a milling speed of 100 r / min, and a mixing time of 2 h to obtain the first mixed powder. After the first mixed powder is mixed with the aluminum powder weighed in Step 1 in an argon atmosphere using a drum ball mill with a ball-to-powder ratio of 5:1, a milling speed of 200 r / min, and a milling time of 4 h to obtain the second mixed powder. Step 3: Place the second mixed powder obtained in Step 2 under a vacuum of <1×10⁻⁶.-3 The powder was filled into a pure aluminum cladding at a pressure of Pa, and then degassed by vibration at 100℃ for 6 hours. After degassed, the powder filling port was sealed with hydraulic clamps. The sealed cladding was then subjected to hot isostatic pressing (HIP) densification, a process divided into two stages: medium-temperature high-pressure and high-temperature high-pressure. The medium-temperature high-pressure stage was held at 450℃ and 150MPa for 4 hours. After holding at 450℃, the temperature was increased to the required temperature for the high-temperature high-pressure stage at a rate of 3℃ / min while maintaining the pressure. The high-temperature high-pressure stage was held at 520℃ and 150MPa for 2 hours. After HIP, the powder was cooled in the furnace to obtain the powder metallurgy composite material billet.

[0037] Step 4: The powder metallurgy billet obtained in Step 3 is subjected to solution treatment and aging heat treatment, specifically: 510℃×4h / water cooling + 120℃×18h / air cooling.

[0038] Step 5: After cooling, the outer casing is removed by machining, and finally an aluminum-based composite material with multi-scale hierarchical structural features is obtained.

[0039] Thirdly, this embodiment provides a high-strength and tough multi-scale graded aluminum-based composite material part, wherein the aluminum-based composite material of the first and second aspects is machined to obtain an engine cylinder head part.

[0040] Example 2 In the first aspect, this embodiment provides a high-strength and tough multi-scale hierarchical aluminum-based composite material, which is composed of the following raw material components by mass percentage: 84.9 wt.% aluminum powder, 12 wt.% silicon powder, 3 wt.% titanium powder, and 0.1 wt.% TiO2 powder.

[0041] The aluminum powder has a particle size of 30 μm; the silicon powder has a particle size of 5 μm and is irregularly shaped; the titanium powder has a particle size of 10 μm and is irregularly shaped; and the TiO2 powder has a particle size of 100 nm and is irregularly shaped.

[0042] Secondly, this embodiment provides a method for preparing a high-strength and tough multi-scale hierarchical aluminum-based composite material, comprising the following steps: Step 1: Weigh the following raw materials by mass percentage: 84.9 wt.% aluminum powder with a particle size of 30 μm, 12 wt.% silicon powder with a particle size of 5 μm, 3 wt.% titanium powder with a particle size of 10 μm, and 0.1 wt.% TiO2 powder with a particle size of 100 nm.

[0043] Step 2: The silicon powder, titanium powder, and TiO2 powder weighed in Step 1 are mixed in an argon atmosphere using a planetary ball mill with a ball-to-powder ratio of 5:1, a milling speed of 200 r / min, and a mixing time of 6 h to obtain the first mixed powder. After mixing, the first mixed powder is mixed with the aluminum powder weighed in Step 1 in an argon atmosphere using a drum ball mill with a ball-to-powder ratio of 10:1, a milling speed of 300 r / min, and a milling time of 8 h to obtain the second mixed powder. Step 3: Place the second mixed powder obtained in Step 2 under a vacuum of <1×10⁻⁶. -3 The powder was filled into a pure aluminum cladding at a pressure of Pa, and then degassed by vibration at 200℃ for 4 hours. After degassed, the powder filling port was sealed with hydraulic clamps. The sealed cladding was then subjected to hot isostatic pressing (HIP) densification, a process divided into two stages: medium-temperature high-pressure and high-temperature high-pressure. The medium-temperature high-pressure stage was held at 520℃ and 180MPa for 1 hour. After holding at 180MPa, the temperature was increased to the required temperature for the high-temperature high-pressure stage at a rate of 5℃ / min while maintaining the pressure. The high-temperature high-pressure stage was held at 570℃ and 180MPa for 0.5 hours. After HIP, the powder was cooled in the furnace to obtain the powder metallurgy composite material billet.

[0044] Step 4: The powder metallurgy billet obtained in Step 3 is subjected to solution treatment and aging heat treatment, specifically: 530℃×2h / water cooling + 140℃×12h / air cooling.

[0045] Step 5: After cooling, the outer casing is removed by machining, and finally an aluminum-based composite material with multi-scale hierarchical structural features is obtained.

[0046] Thirdly, this embodiment provides a high-strength and tough multi-scale graded aluminum-based composite material part, wherein the aluminum-based composite material of the first and second aspects is machined to obtain an engine cylinder head part.

[0047] Figure 3 The X-ray diffraction patterns of the aluminum-based composite materials obtained in Examples 1 and 2 are shown. The diffraction peaks of Ti₅Si₃ are clearly visible, but the formation of ternary intermetallic compounds is not observed. Figure 4 Ti5Si3 particles are also clearly visible in the scanned images (aluminum-based composite material prepared in Example 1); Figure 5 Transmission electron microscopy images (aluminum-based composite material prepared in Example 2) show that micron- and nano-scale Ti5Si3 particles are distributed along the grain boundaries, while nano-Al2O3 particles are generated within the grains.

[0048] at the same time, Figures 6 to 8 The surface scan images further confirmed the phase composition of these particles.

[0049] Example 3 In the first aspect, this embodiment provides a high-strength and tough multi-scale hierarchical aluminum-based composite material, which is composed of the following raw material components by mass percentage: 84.63 wt.% aluminum powder, 12 wt.% silicon powder, 2.37 wt.% titanium powder, and 1 wt.% TiO2 powder.

[0050] The aluminum powder has a particle size of 25 μm; the silicon powder has a particle size of 3 μm and is irregularly shaped; the titanium powder has a particle size of 5 μm and is irregularly shaped; and the TiO2 powder has a particle size of 60 nm and is irregularly shaped.

[0051] Secondly, this embodiment provides a method for preparing a high-strength and tough multi-scale hierarchical aluminum-based composite material, comprising the following steps: Step 1: Weigh the following raw materials by mass percentage: 84.63 wt.% aluminum powder with a particle size of 25 μm, 12 wt.% silicon powder with a particle size of 3 μm, 2.37 wt.% titanium powder with a particle size of 5 μm, and 1 wt.% TiO2 powder with a particle size of 60 nm.

[0052] Step Two: The silicon powder, titanium powder, and TiO2 powder weighed in Step One are mixed in an argon atmosphere using a planetary ball mill. The ball-to-powder ratio is 3:1, the milling speed is 150 r / min, and the mixing time is 4 hours, yielding the first mixed powder. After mixing, the first mixed powder is mixed with the aluminum powder weighed in Step One in an argon atmosphere using a drum ball mill. The ball-to-powder ratio is 8:1, the milling speed is 260 r / min, and the milling time is 6 hours, yielding the second mixed powder. Figure 2 The image shown is a scanning electron microscope image of the second mixed powder (Al-Si-Ti-TiO2 mixed powder). It can be seen that after ball milling, the powder is ground into flakes, and the micron-sized Ti powder and nano-sized TiO2 particles are evenly distributed.

[0053] Step 3: Place the second mixed powder obtained in Step 2 under a vacuum of <1×10⁻⁶. -3 The powder was filled into a pure aluminum cladding at a pressure of Pa, and then degassed by vibration at 300℃ for 2 hours. After degassed, the powder filling port was sealed with hydraulic clamps. The sealed cladding was then subjected to hot isostatic pressing (HIP) densification, a process divided into two stages: medium-temperature high-pressure and high-temperature high-pressure. The medium-temperature high-pressure stage was held at 480℃ and 160MPa for 2 hours. After holding at this temperature, the temperature was increased to the required temperature for the high-temperature high-pressure stage at a rate of 8℃ / min while maintaining the pressure. The high-temperature high-pressure stage was held at 550℃ and 160MPa for 1 hour. After HIP, the powder was cooled in the furnace to obtain the powder metallurgy composite material billet.

[0054] Step 4: The powder metallurgy billet obtained in Step 3 is subjected to solution treatment and aging heat treatment, specifically: 520℃×3h / water cooling + 130℃×15h / air cooling.

[0055] Step 5: After cooling, the outer casing is removed by machining, and finally an aluminum-based composite material with multi-scale hierarchical structural features is obtained.

[0056] like Figure 9 The image shows a high-resolution transmission image of the composite material prepared in this embodiment. As can be seen from the image, a semi-coherent interface is formed between Ti5Si3 and the Al matrix, and the interface is well bonded.

[0057] Thirdly, this embodiment provides a high-strength and tough multi-scale graded aluminum-based composite material part, wherein the aluminum-based composite material of the first and second aspects is machined to obtain a motor housing part.

[0058] Example 4 In the first aspect, this embodiment provides a high-strength and tough multi-scale hierarchical aluminum-based composite material, which is composed of the following raw material components by mass percentage: 98.8 wt.% aluminum powder, 1 wt.% silicon powder, 0.1 wt.% titanium powder, and 0.1 wt.% TiO2 powder.

[0059] The aluminum powder has a particle size of 22 μm; the silicon powder has a particle size of 4 μm and is irregularly shaped; the titanium powder has a particle size of 8 μm and is irregularly shaped; and the TiO2 powder has a particle size of 60 nm and is irregularly shaped.

[0060] Secondly, this embodiment provides a method for preparing a high-strength and tough multi-scale hierarchical aluminum-based composite material, comprising the following steps: Step 1: Weigh the following raw materials by mass percentage: 98.8 wt.% aluminum powder with a particle size of 22 μm, 1 wt.% silicon powder with a particle size of 4 μm, 0.1 wt.% titanium powder with a particle size of 8 μm, and 0.1 wt.% TiO2 powder with a particle size of 60 nm.

[0061] Step 2: The silicon powder, titanium powder, and TiO2 powder weighed in Step 1 are mixed in an argon atmosphere using a planetary ball mill with a ball-to-powder ratio of 2:1, a milling speed of 130 r / min, and a mixing time of 5 h to obtain the first mixed powder. After the first mixed powder is mixed with the aluminum powder weighed in Step 1 in an argon atmosphere using a drum ball mill with a ball-to-powder ratio of 6:1, a milling speed of 240 r / min, and a milling time of 6.5 h to obtain the second mixed powder. Step 3: Place the second mixed powder obtained in Step 2 under a vacuum of <1×10⁻⁶. -3The powder was filled into a pure aluminum cladding at a pressure of Pa, and then degassed by vibration at 150℃ for 6 hours. After degassed, the powder filling port was sealed with hydraulic clamps. The sealed cladding was then subjected to hot isostatic pressing (HIP) densification, a process divided into two stages: medium-temperature high-pressure and high-temperature high-pressure. The medium-temperature high-pressure stage was held at 500℃ and 160MPa for 3 hours. After holding at 500℃, the temperature was increased to the required temperature for the high-temperature high-pressure stage at a rate of 5℃ / min while maintaining the pressure. The high-temperature high-pressure stage was held at 550℃ and 160MPa for 1.5 hours. After HIP, the powder was cooled in the furnace to obtain the powder metallurgy composite material billet.

[0062] Step 4: The powder metallurgy billet obtained in Step 3 is subjected to solution treatment and aging heat treatment, specifically: 520℃×3h / water cooling + 130℃×15h / air cooling.

[0063] Step 5: After cooling, the outer casing is removed by machining, and finally an aluminum-based composite material with multi-scale hierarchical structural features is obtained.

[0064] Thirdly, this embodiment provides a high-strength and tough multi-scale graded aluminum-based composite material part, wherein the aluminum-based composite material of the first and second aspects is machined to obtain an engine cylinder head part.

[0065] Example 5 In the first aspect, this embodiment provides a high-strength and tough multi-scale hierarchical aluminum-based composite material, which is composed of the following raw material components by mass percentage: 90 wt.% aluminum powder, 5 wt.% silicon powder, 3 wt.% titanium powder, and 2 wt.% TiO2 powder.

[0066] The aluminum powder has a particle size of 28 μm; the silicon powder has a particle size of 2 μm and is irregularly shaped; the titanium powder has a particle size of 3 μm and is irregularly shaped; and the TiO2 powder has a particle size of 100 nm and is irregularly shaped.

[0067] Secondly, this embodiment provides a method for preparing a high-strength and tough multi-scale hierarchical aluminum-based composite material, comprising the following steps: Step 1: Weigh the following raw materials by mass percentage: 90 wt.% aluminum powder with a particle size of 28 μm, 5 wt.% silicon powder with a particle size of 2 μm, 3 wt.% titanium powder with a particle size of 3 μm, and 2 wt.% TiO2 powder with a particle size of 100 nm.

[0068] Step 2: The silicon powder, titanium powder, and TiO2 powder weighed in Step 1 are mixed in an argon atmosphere using a planetary ball mill with a ball-to-powder ratio of 4:1, a milling speed of 180 r / min, and a mixing time of 3 h to obtain the first mixed powder. After the first mixed powder is mixed with the aluminum powder weighed in Step 1 in an argon atmosphere using a drum ball mill with a ball-to-powder ratio of 8:1, a milling speed of 280 r / min, and a milling time of 5 h to obtain the second mixed powder. Step 3: Place the second mixed powder obtained in Step 2 under a vacuum of <1×10⁻⁶. -3 The powder was filled into a pure aluminum cladding at a pressure of 180 MPa and then degassed by vibration at 260°C for 4 hours. After degassed, the powder filling port was sealed with hydraulic clamps. The sealed cladding was then subjected to hot isostatic pressing (HIP) densification, a process divided into two stages: medium-temperature high-pressure and high-temperature high-pressure. The medium-temperature high-pressure stage was held at 520°C and 180 MPa for 2 hours. After holding at 520°C, the temperature was increased to the required temperature for the high-temperature high-pressure stage at a rate of 6°C / min while maintaining the pressure. The high-temperature high-pressure stage was held at 560°C and 180 MPa for 1 hour. After HIP, the powder was cooled in the furnace to obtain the powder metallurgy composite material billet.

[0069] Step 4: The powder metallurgy billet obtained in Step 3 is subjected to solution treatment and aging heat treatment, specifically: 530℃×2h / water cooling + 140℃×12h / air cooling.

[0070] Step 5: After cooling, the outer casing is removed by machining, and finally an aluminum-based composite material with multi-scale hierarchical structural features is obtained.

[0071] Thirdly, this embodiment provides a high-strength and tough multi-scale graded aluminum-based composite material part, wherein the aluminum-based composite material of the first and second aspects is machined to obtain a motor housing part.

[0072] Comparative Example 1 The difference between this comparative example and Example 1 lies in the different particle size distribution range and proportion of raw materials, as well as the hot isostatic pressing process. In this comparative example, the aluminum-based composite material is composed of the following raw material components by mass percentage: 82 wt.% aluminum powder, 12 wt.% silicon powder, 3.5 wt.% titanium powder, and 2.5 wt.% TiO2 powder.

[0073] The aluminum powder has a particle size of 40 μm; the silicon powder has a particle size of 10 μm and is irregularly shaped; the titanium powder has a particle size of 15 μm and is irregularly shaped; and the TiO2 powder has a particle size of 120 nm and is irregularly shaped.

[0074] Secondly, this embodiment provides a method for preparing an aluminum-based composite material, comprising the following steps: Step 1: Weigh the following raw materials by mass percentage: 82 wt.% aluminum powder with a particle size of 40 μm, 12 wt.% silicon powder with a particle size of 10 μm, 3.5 wt.% titanium powder with a particle size of 15 μm, and 2.5 wt.% TiO2 powder with a particle size of 120 nm.

[0075] Step 2: The silicon powder, titanium powder, and TiO2 powder weighed in Step 1 are mixed in an argon atmosphere using a planetary ball mill with a ball-to-powder ratio of 1:1, a milling speed of 100 r / min, and a mixing time of 2 h to obtain the first mixed powder. After the first mixed powder is mixed with the aluminum powder weighed in Step 1 in an argon atmosphere using a drum ball mill with a ball-to-powder ratio of 5:1, a milling speed of 200 r / min, and a milling time of 4 h to obtain the second mixed powder. Step 3: Place the second mixed powder obtained in Step 2 under a vacuum of <1×10⁻⁶. -3 The powder was filled into a pure aluminum cladding at a pressure of 150 MPa and then degassed by vibration at 100°C for 6 hours. After degassed, the powder filling port was sealed by hydraulic clamps. The sealed cladding was then subjected to hot isostatic pressing (HIP) densification at 600°C and 150 MPa for 4 hours. After HIP, the powder was cooled in the furnace to obtain the powder metallurgy composite material billet.

[0076] Step 4: The powder metallurgy billet obtained in Step 3 is subjected to solution treatment and aging heat treatment, specifically: 510℃×4h / water cooling + 120℃×18h / air cooling.

[0077] Step 5: After cooling, the outer casing is removed by machining, and the aluminum-based composite material is finally obtained.

[0078] Comparative Example 2 This comparative example provides a method for preparing Al-Si-Ti composite materials, specifically including the following steps: Step 1: Weigh the following raw materials by mass percentage: 85.63 wt.% aluminum powder with a particle size of 25 μm, 12 wt.% silicon powder with a particle size of 3 μm, and 2.37 wt.% titanium powder with a particle size of 5 μm. The sum of the mass percentages of each component is 100%.

[0079] Step 2: The silicon powder, titanium powder and aluminum powder weighed in Step 1 are mixed in an argon atmosphere using a planetary ball mill. The ball-to-powder ratio is 8:1, the ball milling speed is 260 r / min, and the ball milling time is 6 h to obtain the first mixed powder. Step 3: Place the first mixed powder obtained in Step 2 under a vacuum of <1×10⁻⁶. -3The powder was filled into a pure aluminum cladding at a pressure of Pa, and then degassed by vibration at 300℃ for 2 hours. After degassed, the powder filling port was sealed with hydraulic clamps. The sealed cladding was then subjected to hot isostatic pressing (HIP) densification, a process divided into two stages: medium-temperature high-pressure and high-temperature high-pressure. The medium-temperature high-pressure stage was held at 480℃ and 160MPa for 2 hours. After holding at this temperature, the temperature was increased to the required temperature for the high-temperature high-pressure stage at a rate of 8℃ / min while maintaining the pressure. The high-temperature high-pressure stage was held at 550℃ and 160MPa for 1 hour. After HIP, the powder was cooled in the furnace to obtain the powder metallurgy composite material billet.

[0080] Step 4: The powder metallurgy billet obtained in Step 3 is subjected to solution treatment and aging heat treatment. The specific process is: 520℃×3h / water cooling + 130℃×15h / air cooling to obtain powder metallurgy composite material parts.

[0081] Step 5: The part obtained in Step 4 is machined to remove the cladding, and finally Al-Si-Ti composite material is obtained.

[0082] To demonstrate the efficacy of this invention, the inventors conducted room temperature tensile and 300°C high-temperature tensile property tests on all aluminum-based composite materials prepared in the embodiments and comparative examples. The room temperature tensile and high-temperature tensile property tests were performed according to ASTM A370-24a and ASTM E21-2020 standards, respectively. The specific test results are shown in Table 1 below.

[0083] Table 1. Results of room temperature and high temperature tensile properties of the composite materials in the examples and comparative examples. The test results above show that the multi-scale hierarchical aluminum-based composite material prepared by this invention exhibits excellent comprehensive mechanical properties over a wide temperature range: at room temperature, tensile strength > 400 MPa, yield strength > 300 MPa, and elongation > 4%; at 300℃, tensile strength > 150 MPa, yield strength > 100 MPa, and elongation > 10%. These performance indicators fully demonstrate that this invention achieves a synergistic improvement in the strength, plasticity, and high-temperature performance of the composite material, meeting the performance requirements under service conditions such as automotive engine cylinder heads and motor housings.

[0084] Combination Figure 10It can be seen that the room temperature tensile fracture profile of the multi-scale hierarchical aluminum matrix composite material prepared by this invention exhibits typical ductile fracture characteristics. White micron-sized Ti5Si3 particles are dispersed at the grain boundaries and do not show debonding from the matrix after tensile fracture, exhibiting obvious fracture characteristics. This indicates that the Ti5Si3 particles generated by the Ti-Si interdiffusion reaction using micron-sized titanium particles as templates during the preparation process of medium-temperature high-pressure and high-temperature high-pressure powder metallurgy and solution + aging heat treatment have good bonding with the matrix interface. Figure 9 This effectively strengthens the load transfer process; simultaneously, the grain boundary nano-Ti5Si3 particles and intragranular nano-Al2O3 particles generated through the Al-Si-TiO2 interdiffusion reaction hinder grain boundary migration and dislocation movement, enhancing the strain hardening capacity of the matrix. They also suppress rapid crack propagation through deflection cracks, exhibiting a serrated fracture surface, thus providing a microstructural basis for a good match between room temperature strength and toughness. High-temperature fracture microstructure shows (… Figure 11 The multi-scale hierarchical structure, composed of micron-nano Ti5Si3 particles at grain boundaries and nano-Al2O3 particles within grains, strengthens the matrix alloy properties, pins grain boundary movement and dislocation climb at high temperatures, mitigates the high-temperature softening behavior of the matrix alloy, exhibits a diffuse crack initiation effect, suppresses interfacial cracking at high temperatures, promotes the synergistic deformation ability of the matrix and reinforcing phase particles, and improves the high-temperature mechanical properties of the composite material. Under the synergistic effect of the above factors, the multi-scale hierarchical aluminum matrix composite material developed in this invention achieves a synergistic improvement in room temperature strength and toughness and high-temperature performance.

[0085] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0086] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A high-strength, high-toughness, multi-scale hierarchical aluminum-based composite material, characterized in that, It includes a matrix phase and a reinforcing phase; the matrix phase is an aluminum matrix, and the reinforcing phase includes eutectic silicon particles distributed in the aluminum matrix, micron and nano Ti5Si3 particles generated in situ at the grain boundaries, and nano Al2O3 particles within the grains. The in situ generated reinforcing phase constitutes a multi-scale hierarchical structure.

2. The high-strength and high-toughness multi-scale hierarchical aluminum-based composite material according to claim 1, characterized in that, The aluminum-based composite material is composed of the following raw material components by mass percentage: 83~98.8 wt.% aluminum powder, 1~12 wt.% silicon powder, 0.1~3 wt.% titanium powder, and 0.1~2 wt.% TiO2 powder.

3. The high-strength and high-toughness multi-scale hierarchical aluminum-based composite material according to claim 2, characterized in that, The aluminum powder has a particle size of 20-30 μm; the silicon powder has a particle size of 1-5 μm; the titanium powder has a particle size of 1-10 μm; and the TiO2 powder has a particle size of 20-100 nm.

4. A method for preparing a high-strength, high-toughness, multi-scale hierarchical aluminum-based composite material, characterized in that, The method for preparing the aluminum-based composite material according to any one of claims 1 to 3 comprises the following steps: Step 1: Weigh the raw materials according to the proportion of raw material components set in claim 2 or 3, then ball mill and mix the silicon powder, titanium powder and TiO2 powder under an inert atmosphere, and then add aluminum powder and continue ball milling and mixing to obtain a mixed powder; Step 2: The mixed powder obtained in Step 1 is loaded into a sleeve and degassed and sealed. Then, it is subjected to hot isostatic pressing and cooled to obtain the composite material blank. Step 3: The composite material blank obtained in Step 2 is heat-treated, and then the cladding is removed by machining to obtain an aluminum-based composite material with a multi-scale hierarchical structure.

5. The method for preparing the high-strength and tough multi-scale hierarchical aluminum-based composite material according to claim 4, characterized in that, In step one, silicon powder, titanium powder and TiO2 powder are mixed using a planetary ball mill with a ball-to-material ratio of 1 to 5:1, a milling speed of 100 to 200 r / min, and a time of 2 to 6 hours. Then, aluminum powder is added and mixed again using a planetary ball mill or a drum ball mill with a ball-to-material ratio of 5 to 10:1, a milling speed of 200 to 300 r / min, and a time of 4 to 8 hours.

6. The method for preparing the high-strength and high-toughness multi-scale hierarchical aluminum-based composite material according to claim 4, characterized in that, In step two, when the vacuum degree is <1×10 -3 The mixed powder is loaded into a package under Pa conditions, and then degassed by vibration at a temperature of 100~300℃ for 2~6 hours.

7. The method for preparing the high-strength and tough multi-scale hierarchical aluminum-based composite material according to claim 4, characterized in that, In step two, the hot isostatic pressing process includes a medium-temperature high-pressure stage and a high-temperature high-pressure stage. The parameters for the medium-temperature high-pressure stage are: temperature 450~520℃, pressure 150~180MPa, and holding time 1~4h. After the holding time is completed, the temperature is raised to the high-temperature high-pressure stage while maintaining the pressure. The parameters for the high-temperature high-pressure stage are: temperature 520~570℃, pressure 150~180MPa, and holding time 0.5~2h.

8. The method for preparing the high-strength and high-toughness multi-scale hierarchical aluminum-based composite material according to claim 4, characterized in that, In step three, the heat treatment process includes solution treatment and aging treatment, with the following parameters: (510~530)℃×(2~4)h / water cooling + (120~140)℃×(12~18)h / air cooling.

9. A high-strength, high-toughness, multi-scale hierarchical aluminum-based composite material component, characterized in that, The aluminum-based composite material according to any one of claims 1 to 3 or the aluminum-based composite material prepared by any one of claims 4 to 8 is obtained by processing.

10. The high-strength and high-toughness multi-scale hierarchical aluminum matrix composite material part according to claim 9, characterized in that, At room temperature, its tensile strength is >400 MPa, yield strength is >300 MPa, and elongation is >4%; at 300℃, its tensile strength is >150 MPa, yield strength is >100 MPa, and elongation is >10%.

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