CN-122013073-A - Method for improving modulus, toughness and heat resistance of aluminum matrix composite material by utilizing cooperation of silicon carbide whisker network and intragranular rare earth coverage precipitated phase

CN122013073ACN 122013073 ACN122013073 ACN 122013073ACN-122013073-A

Abstract

The invention discloses a method for improving modulus, toughness and heat resistance of an aluminum-based composite material by utilizing a silicon carbide whisker network and an intragranular rare earth coverage precipitated phase in a synergistic manner, and belongs to the field of aluminum-based composite materials. Solves the problems that the existing silicon carbide whisker reinforced aluminum-based composite material is difficult to realize matrix structure homogenization and refinement, and meanwhile, the segregation behavior of rare earth elements at various interfaces such as a reinforcement body/matrix, a precipitated phase/matrix and the like can not be accurately regulated and controlled, and a multistage reinforced structure with high thermal stability can not be constructed. The method comprises the steps of preparing a silicon carbide whisker prefabricated block, preparing an alloy melt, preparing an aluminum-based composite material by extrusion infiltration, and performing tandem heat treatment-hot extrusion-heat treatment synergistic process. The invention is used for improving the modulus, the toughness and the heat resistance of the aluminum-based composite material by utilizing the cooperation of the silicon carbide whisker network and the intragranular rare earth coverage precipitation phase.

Inventors

ZHANG XUEXI
LAI ZHIWEI
QIAN MINGFANG
GENG LIN

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260512
Application Date: 20260319

Claims (10)

1. A method for improving modulus, toughness and heat resistance of an aluminum matrix composite by utilizing cooperation of a silicon carbide whisker network and an intragranular rare earth coverage precipitation phase is characterized by comprising the following steps: 1. Preparing a silicon carbide whisker precast block: uniformly stirring and dispersing the rinsed silicon carbide whisker solution and water-soluble organosol to obtain whisker slurry, adding the whisker slurry into a die with water seepage holes arranged below, standing until water is fully seeped out, prepressing to obtain a preliminary formed whisker precast block, sintering and shaping the preliminary formed whisker precast block, and removing residual glue to obtain the silicon carbide whisker precast block; 2. Preparation of alloy melt: Weighing raw materials according to the mass percentage of each metal element in the alloy matrix material, and melting the raw materials in an argon atmosphere to obtain alloy aluminum liquid; 3. Preparing an aluminum-based composite material by extrusion infiltration: placing the silicon carbide whisker precast block in the middle of an extrusion die, heating and preserving heat along with a furnace, pouring part of alloy aluminum liquid into a gap between the silicon carbide whisker precast block and the extrusion die, reheating and preserving heat until the alloy aluminum liquid is solidified to fix the silicon carbide whisker precast block, stopping heating after preserving heat, pouring the rest alloy aluminum liquid into the gap between the silicon carbide whisker precast block and the extrusion die while stopping heating, carrying out secondary pressurization in the cooling process along with the furnace, and finally demoulding and turning away the aluminum alloy which is not infiltrated around to obtain an aluminum-based composite material cast ingot; 4. tandem heat treatment-hot extrusion-heat treatment synergistic process: ① Carrying out secondary homogenization treatment on the aluminum-based composite material cast ingot, taking out, and carrying out water quenching and cooling to obtain a homogenized composite material; ② Carrying out large-deformation hot extrusion on the homogenized composite material, and finally carrying out water quenching and cooling to obtain an extruded bar; ③ Carrying out short-time high-temperature solid solution treatment on the extruded bar, taking out, quenching with water, cooling to obtain a bar after solid solution, ④ And carrying out multistage aging treatment on the rod after solid solution to obtain the aluminum-based composite material with the synergistic enhancement of the silicon carbide whisker network and the intracrystalline rare earth covered precipitated phase.
2. The method for improving the modulus, the toughness and the heat resistance of the aluminum matrix composite material by utilizing the synergy of a silicon carbide whisker network and an intra-crystal rare earth coating precipitation phase is characterized in that the rinsed silicon carbide whisker solution in the first step is prepared by soaking the silicon carbide whisker in mixed acid, stirring for 2-12 h under the conditions of room temperature and stirring speed of 200-600 r/min, then preserving heat for 6-24 h under the conditions of temperature of 75-90 ℃, stirring for 1-2 h under the conditions of room temperature and stirring speed of 200-600 r/min, obtaining the pickled silicon carbide whisker, adding distilled water into the pickled silicon carbide whisker, standing to precipitate the whisker, then removing water, repeatedly adding distilled water, precipitating and removing water for a plurality of times until the removed water pH is 6-7, and finally draining to obtain the rinsed silicon carbide whisker solution; The silicon carbide whisker has a diameter of 100 nm-1.5 mu m and a length of 10 mu m-100 mu m, the mixed acid is formed by mixing hydrofluoric acid solution, sulfuric acid solution and water, the volume ratio of the hydrofluoric acid solution to the sulfuric acid solution is 1 (0.5-1), the volume ratio of the total volume of the hydrofluoric acid solution to the sulfuric acid solution to the volume ratio of the water is 1 (5-9), the mass percentage of the hydrofluoric acid solution is 49%, and the mass percentage of the sulfuric acid solution is 98%.
3. The method for improving the modulus, the toughness and the heat resistance of the aluminum matrix composite by utilizing the synergy of a silicon carbide whisker network and an intragranular rare earth coating precipitated phase is characterized in that the water-soluble organosol in the step one consists of water, silica gel and polysilazane, the volume ratio of the polysilazane to the silica gel is 1 (2-4), the volume ratio of the polysilazane to the water is 1 (20-50), the mass percentage of the rinsed silicon carbide whiskers in the rinsed silicon carbide whisker solution in the step one is 25% -35%, the water-soluble organosol is weighed by adding 0.5-1.5 ml of the water-soluble organosol into each 1g of the rinsed silicon carbide whisker solution in the step one, and the pre-pressing in the step one is performed for 2-24 h under the condition that the pressure is 10-100 MPa.
4. The method for improving the modulus, the toughness and the heat resistance of the aluminum-based composite material by utilizing the cooperation of a silicon carbide whisker network and an intra-crystal rare earth coating precipitation phase is characterized in that the sintering shaping and the residual glue removal in the first step are carried out according to the following steps of firstly preserving heat for 12-36 h under the condition that the temperature is 40-60 ℃, then preserving heat for 12-36 h under the condition that the temperature is 80-90 ℃, then preserving heat for 12-36 h under the condition that the temperature is 100-120 ℃, then heating to 700-900 ℃ at the rate of not higher than 2 ℃ per minute, preserving heat for 1-4 h under the condition that the temperature is 700-900 ℃, then cooling to room temperature along with a furnace, and finally obtaining the silicon carbide prefabricated block with the compression strength of 7-10 MPa under the condition that the vacuum and the temperature are 1100-1300 ℃ and 1-4 h.
5. The method for improving the modulus, the toughness and the heat resistance of an aluminum-based composite material by utilizing the cooperation of a silicon carbide whisker network and an intragranular rare earth coating precipitated phase, according to claim 1, wherein the alloy base material in the second step is an Al-RE alloy, an Al-Cu-Mg-RE alloy, an Al-Ni-Fe-RE alloy, an Al-Cu-Mg-Ag-RE alloy or an Al-Zn-Mg-Cu-RE alloy, wherein RE is one or a combination of several of Ce, sc, Y and Zr.
6. The method for improving the modulus, the toughness and the heat resistance of the aluminum-based composite material by utilizing the synergy of a silicon carbide whisker network and an intragranular rare earth coating precipitated phase, which is characterized in that when the alloy base material in the second step is an Al-Cu-Mg-Ag-RE alloy, the Al-Cu-Mg-Ag-RE alloy consists of 3.6 to 6.0 percent of Cu, 0.4 to 2.0 percent of Mg, 0.2 to 0.8 percent of Mn, 0.3 to 1.0 percent of Ag, 0.1 to 2.0 percent of RE and the balance of Al according to the mass percentage, wherein RE is one or the combination of more of Ce, sc, Y and Zr; the raw materials in the second step are pure Al, al-Mn alloy, al-Cu alloy, pure Ag, pure Mg and Al-RE alloy, wherein the Al-RE alloy is one or a combination of several of Al-Ce alloy, al-Sc alloy, al-Y alloy and Al-Zr alloy, the melting in the argon atmosphere in the second step is specifically carried out according to the following steps that ① heats and melts pure Al, al-Mn alloy, al-Cu alloy and pure Ag in the argon atmosphere at 760-800 ℃ to obtain a first melt, ② presses a getter wrapped by aluminum foil into the bottom of the first melt by a bell jar in the argon atmosphere at 750-780 ℃ to obtain a melt after slagging off after the getter and the first melt react to completely generate no gas, the mass ratio of the getter and the first melt is 1 (0.005-0.02), the getter is hexachloroethane, the getter is ③ in the argon atmosphere at 750-780 ℃, pressing pure Mg and Al-RE alloy wrapped by aluminum foil into the slag-removed melt by using a bell jar, standing for 5 min-30 min to obtain a second melt, and stirring the second melt for 5 min-15 min under the conditions of argon atmosphere, 760-850 ℃ and stirring speed of 200-800 r/min to obtain alloy aluminum liquid.
7. The method for improving the modulus, the toughness and the heat resistance of the aluminum matrix composite by utilizing the cooperation of a silicon carbide whisker network and an intra-crystal rare earth coverage precipitation phase is characterized in that an extrusion die in the step three is composed of a die sleeve and a bottom graphite gasket, the bottom graphite gasket is provided with a vent hole, a silicon carbide whisker prefabricated block is placed in the middle of the extrusion die and heated and insulated along with a furnace for 0.5-2 h under the condition that the temperature is 560-620 ℃, the heating and the insulation are carried out in the step three until an alloy aluminum liquid is solidified to fix the silicon carbide whisker prefabricated block, the reheating is carried out in the step three, the reheating is carried out at 560-620 ℃ and the temperature is 560-620 ℃, the insulation is carried out for 30-60 min, the secondary pressurization in the step three is carried out under the condition that the low pressure is 5-6 MPa, the pressure is 1-2 min, and the pressure is maintained for 5-230 min under the condition that the high pressure is 200-200 MPa.
8. The method for improving the modulus, the toughness and the heat resistance of the aluminum matrix composite by utilizing the cooperation of a silicon carbide whisker network and an intra-crystal rare earth coverage precipitation phase, which is disclosed in claim 1, is characterized in that the secondary homogenization treatment in the step four ① is specifically carried out by firstly preserving heat for 48-96 h under the condition that the temperature is 420-490 ℃ and then preserving heat for 4-10 h under the condition that the temperature is 500-530 ℃.
9. The method for improving the modulus, the toughness and the heat resistance of the aluminum-based composite material by utilizing the cooperation of a silicon carbide whisker network and an intra-crystal rare earth coating precipitation phase is characterized in that the large-deformation hot extrusion in the step four ② is specifically carried out by firstly preserving heat for 0.5-2 hours under the condition that the temperature is 300-520 ℃, then carrying out hot extrusion deformation according to the extrusion ratio (9-40): 1 under the condition that the temperature is 300-520 ℃ and the metal outflow speed is 0.5-3 m/min, and the short-time high-temperature solution treatment in the step four ③ is specifically carried out by preserving heat for 10-60 min under the condition that the temperature is 530-600 ℃.
10. The method for improving the modulus, the toughness and the heat resistance of the aluminum matrix composite by utilizing the cooperation of a silicon carbide whisker network and an intra-crystal rare earth coating precipitation phase is characterized in that the multistage aging treatment in the step four ④ is specifically carried out by firstly preserving heat for 1-8 hours at the temperature of 150-200 ℃, then carrying out water quenching cooling to room temperature after preserving heat, then preserving heat for 0-16 hours at the temperature of 200-250 ℃, carrying out water quenching cooling to room temperature after preserving heat, finally carrying out water quenching cooling to room temperature after preserving heat for 0-16 hours at the temperature of 250-300 ℃, wherein the volume percentage of the silicon carbide whisker in the aluminum matrix composite which is cooperatively enhanced by the silicon carbide whisker network and the intra-crystal rare earth coating precipitation phase in the step four ④ is 15-40%.

Description

Method for improving modulus, toughness and heat resistance of aluminum matrix composite material by utilizing cooperation of silicon carbide whisker network and intragranular rare earth coverage precipitated phase Technical Field The invention belongs to the field of aluminum-based composite materials. Background The high-strength heat-resistant aluminum alloy and the composite material thereof are developed for meeting the development requirement of advanced spacecrafts, and the final aim is to obtain the light high-strength heat-resistant material which can be stably served in the temperature range of 200-400 ℃. In recent years, the research of the heat-resistant aluminum alloy has obtained remarkable results, and novel microstructure design strategies such as precipitation phase interface atomic segregation, hetero-atomic gap position ordering, multi-level hetero-phase interface coherent coupling and the like are formed. Wherein, the micro-alloying deformation heat-resistant aluminum alloy (such as Al-Cu-Mg-Fe-Ni system, al-Cu-Mn system and Al-Cu-Mg-Ag system) under the ingot metallurgy condition obviously improves the high temperature mechanical properties by introducing transition group and rare earth elements (publication numbers CN 115323230A and CN 102796927A). However, although microalloying and heat treatment optimization can improve the heat resistance of aluminum alloy to a certain extent, the problems of poor dimensional stability and the like caused by the inherent upper limit of heat resistance and higher thermal expansion coefficient are difficult to fundamentally solve, and the application of the aluminum alloy under higher-end working conditions is limited. Unlike traditional aluminum alloy, the aluminum-based composite material has the high specific modulus and high strength characteristics of the toughness of the matrix alloy and the reinforcement by introducing the high-heat-stability reinforcement (such as ceramic particles and whiskers) from outside or generating the high-heat-stability reinforcement in situ in the matrix, has higher specific strength and specific stiffness, also has better heat conductivity, low expansion and dimensional stability, is an ideal lightweight structural material in the aerospace field, and has wide application prospect (publication numbers CN 112301298B and CN 114134370A). Currently, the research leading edge and the consensus of improving the heat resistance of aluminum-based composite materials are that the interface and the matrix are cooperatively reinforced. The core strategy is that through microalloying of rare earth (such as Sc, ce, Y and the like), on one hand, a thermally stable nano precipitated phase is formed in an aluminum matrix to strengthen the matrix, and on the other hand, selective segregation of the elements at a key interface is induced, so that the thermal stability of interface combination is improved from the chemical nature. Silicon carbide whisker (SiCw) is an ideal reinforcement for constructing a three-dimensional reinforcement network due to its one-dimensional monocrystalline structure and high thermal stability. Therefore, the combination of the bearing advantage of SiCw and the stabilizing effect of rare earth on an interface/matrix through heat treatment is considered to be an ideal way for realizing the integration of high modulus, toughness and heat resistance of materials. However, the theoretical perfect strategy is converted into a controllable preparation process, so that the core bottleneck of whisker debonding caused by interfacial weakening of the SiCw reinforced aluminum-based composite material at high temperature is systematically solved, and the prior art faces the following deep and mutually coupled process contradictions: 1. The ' target of the interface segregation is not reachable ' contradiction that the prior ' rare earth interface segregation ' technology successful in aluminum alloy mainly aims at the interface of intermetallic compound precipitated phases (such as theta ' phase) in a matrix. SiCw and aluminum are heterogeneous systems with different thermophysical properties, and the segregation behavior, effective structure and required process conditions of rare earth elements at the ceramic/metal interface of SiCw/Al are possibly completely different. By applying a mature heat treatment system for a precipitated phase interface, an effective and stable segregation layer cannot be formed on the most critical reinforcement/matrix interface, so that the interface high-temperature reinforcement target falls down. 2. The contradiction of "process condition conflict" for tissue preparation and interface optimization is that to obtain a high performance composite, as-cast tissue must be crushed, densified and SiCw distribution optimized by large deformation hot extrusion (e.g., to build a three-dimensional network). However, the brittle low-melting phase in the as-cast structure is the source of extrus