CN117444179A - A (T) suitable for a pistoni 3 SiC 2 +SiC)/Al-Si composite material and preparation method thereof - Google Patents

A (T) suitable for a pistoni 3 SiC 2 +SiC)/Al-Si composite material and preparation method thereof Download PDF

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CN117444179A
CN117444179A CN202311194296.0A CN202311194296A CN117444179A CN 117444179 A CN117444179 A CN 117444179A CN 202311194296 A CN202311194296 A CN 202311194296A CN 117444179 A CN117444179 A CN 117444179A
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sic
temperature
composite material
freezing
porous ceramic
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林波
肖华强
聂蒙
王雪健
莫太骞
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Guizhou University
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Guizhou University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D23/00—Casting processes not provided for in groups B22D1/00 - B22D21/00
    • B22D23/04—Casting by dipping
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
    • C04B35/5607—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on refractory metal carbides
    • C04B35/5611—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on refractory metal carbides based on titanium carbides
    • C04B35/5615—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on refractory metal carbides based on titanium carbides based on titanium silicon carbides
    • C—CHEMISTRY; METALLURGY
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    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/62605—Treating the starting powders individually or as mixtures
    • C04B35/6261—Milling
    • C04B35/62615—High energy or reactive ball milling
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    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/06—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances
    • C04B38/0605—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances by sublimating
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
    • C04B41/51—Metallising, e.g. infiltration of sintered ceramic preforms with molten metal
    • C04B41/515—Other specific metals
    • C04B41/5155—Aluminium
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
    • C04B41/81—Coating or impregnation
    • C04B41/85—Coating or impregnation with inorganic materials
    • C04B41/88—Metals
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/10—Alloys containing non-metals
    • C22C1/1005—Pretreatment of the non-metallic additives
    • C22C1/1015—Pretreatment of the non-metallic additives by preparing or treating a non-metallic additive preform
    • C22C1/1021—Pretreatment of the non-metallic additives by preparing or treating a non-metallic additive preform the preform being ceramic
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C1/00—Making non-ferrous alloys
    • C22C1/10—Alloys containing non-metals
    • C22C1/1036—Alloys containing non-metals starting from a melt
    • C22C1/1047—Alloys containing non-metals starting from a melt by mixing and casting liquid metal matrix composites
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C21/00—Alloys based on aluminium
    • C22C21/02—Alloys based on aluminium with silicon as the next major constituent
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
    • C22C32/0047—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents
    • C22C32/0052—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents only carbides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/0084—Pistons  the pistons being constructed from specific materials

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  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
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  • Inorganic Chemistry (AREA)
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  • Manufacture Of Alloys Or Alloy Compounds (AREA)

Abstract

The invention discloses a piston (Ti 3 SiC 2 +SiC)/Al-Si composite material and a preparation method thereof. The preparation method of the composite material comprises the following steps: preparation of a solid material having radial (Ti 3 SiC 2 +SiC) lamellar porous ceramic skeleton, and completely immersing Al-Si alloy into the porous ceramic skeleton by extrusion infiltration to obtain radial lamellar (Ti) 3 SiC 2 +sic)/Al-Si composite. The composite material prepared by the invention has good high-temperature compressive strength, high-temperature bending strength, fracture toughness and high-temperature wear resistance, the high-temperature performance of the composite material is greatly improved relative to that of an Al-Si matrix, and the composite material can be used for preparing high-performance piston members by regulating and controlling the ceramic content and lamellar arrangement of different parts.

Description

A piston (Ti 3 SiC 2 +SiC)/Al-Si composite material and preparation method thereof
Technical Field
The invention relates to the technical field of Al-Si composite materials, in particular to a composite material suitable for a piston (Ti 3 SiC 2 +SiC)/Al-Si composite material and a preparation method thereof.
Background
The engine piston, the connecting rod and the cylinder cover are core parts of the fuel motor vehicle, and in order to achieve the aim of energy conservation and emission reduction, the parts are required to be designed in a lightweight way. Among a plurality of light materials, al-Si alloy becomes an ideal material for manufacturing pistons due to the advantages of low density, fast heat conduction, high specific strength and the like. As the exhaust emission standards of automobiles become more stringent, it is a trend to improve the thermal efficiency of engines, which puts higher demands on the high temperature resistance and wear resistance of pistons. Research shows that the addition of ceramic particles to aluminum alloys can significantly enhance the high temperature resistance and wear resistance, but when the ceramic particle content is too high, the toughness of the composite material is drastically reduced, which limits the application of the high ceramic content aluminum-based composite material. Naturally, the adoption of a bionic structure design is an effective way for improving the toughness of the aluminum-based composite material, wherein the shell-like layered material is a template with more applications. The book is provided withThe invention adopts a freezing casting process to synthesize the ceramic skeleton (Ti) with a net-shaped structure at the top and a radial lamellar structure at the circumference part in situ 3 SiC 2 +sic). Wherein Ti3SiC2 has the property of metal ceramic, and has self-lubricating effect and high heat conduction performance at high temperature. The SiC ceramic has the advantages of high hardness, high heat resistance and high heat conduction. The Al-Si alloy is infiltrated into the ceramic framework by adopting a pressure infiltration process, so that the composite material with the outer layer of ceramic and the inner layer of aluminum alloy can be obtained, and the advantages of external hardness and internal toughness can be exerted. The ceramic reinforced aluminum-based composite material with the outer part of the laminated structure and the inner part of the piston made of aluminum alloy has excellent strength, toughness, high temperature resistance and wear resistance, and can be widely applied to high-power diesel engine pistons.
Disclosure of Invention
The invention aims to solve the problem of poor toughness of an aluminum-based composite material with high ceramic content and provides a method for preparing the aluminum-based composite material (Ti 3 SiC 2 The invention benefits from various toughening mechanisms caused by lamellar structure, and Ti generated by regulating in-situ reaction 3 SiC 2 And SiC, so that the composite material has excellent high temperature resistance and wear resistance. Can be applied to the fields of aerospace, automobiles, communication and the like with high requirements on high-performance light structural materials.
In order to achieve the above purpose, the present invention provides the following technical solutions:
the utility model provides a freezing mould, includes metal tray, copper cup, first heat-proof stick and second heat-proof stick, copper cup bottom set up in the metal tray, be provided with the heat-conducting medium in the metal tray, the second heat-proof stick transversely run through copper cup and first heat-proof stick, copper cup endotheca is equipped with first heat-proof stick, place thick liquids in the space between copper cup and first heat-proof stick, the second heat-proof stick. The first heat insulation rod and the second heat insulation rod are preferably made of polytetrafluoroethylene rods.
Preferably, the metal plate is made of stainless steel, and the heat conducting medium is alcohol.
The invention also provides a piston (Ti 3 SiC 2 +SiC)/Al-Si complexThe preparation method of the composite material comprises the following steps: preparation of (Ti having radial lamellar structure using the freezing mold 3 SiC 2 +SiC) porous ceramic skeleton, and completely immersing Al-Si alloy into the porous ceramic skeleton by extrusion infiltration to obtain (Ti) 3 SiC 2 +sic)/Al-Si composite.
Preferably, the preparation method specifically comprises the following steps:
(1) Mixing powder: the mass ratio is 5:3:2-2.85 TiH 2 Pouring TiC and SiC into a container, adding water, ammonium polyacrylate and neutral silica sol, charging high-purity argon, and ball milling for 1-3h to obtain the Ti-containing alloy 3 SiC 2 And SiC particles are uniformly dispersed;
(2) Freezing: placing the unidirectional freezing mold in a freezing container with the temperature of minus 30 ℃ to minus 35 ℃, pouring the slurry obtained in the step (1) into the container for freezing for 1.0 to 1.5 hours, and demolding to obtain blocks with alternately arranged ceramic layers and ice layers;
(3) And (3) drying at low temperature: drying at low temperature in a low-temperature dryer for 24-48 hours to obtain a dried green body;
(4) Sintering: sintering the green body under the protection of inert gas to obtain a layered porous ceramic skeleton;
(5) Infiltration: firstly placing a porous ceramic skeleton preheated at 280-320 ℃ into a mould, then pouring refined Al-Si alloy melt, maintaining the pressure for 0.8-1.2min under the pressure of 32-37MPa, and demoulding to obtain the (Ti) with radial lamellar structure 3 SiC 2 +sic)/Al-Si composite. The die in the step (5) is preferably an H13 steel die.
During impregnation, (Ti) 3 SiC 2 The ceramic sheet layers of the +SiC)/Al-Si composite remain substantially intact, and the pores between the sheet layers are completely filled with molten aluminum alloy, forming a radial sheet structure of alternating ceramic and aluminum layers. The composite material can be prepared into Ti through regulating and controlling in-situ reaction 3 SiC 2 And SiC, which is an ideal material for preparing high-performance pistons.
The invention adopts in-situ self-primingPreparation by biotechnology (Ti) 3 SiC 2 +SiC), compared with other methods, the in-situ autogenous reinforcement has good interface bonding property and wettability with a matrix, so that the metal matrix composite material has excellent and stable performance. The reaction formula is as follows:
TiH 2 →Ti+H 2 ；2Ti+TiC+SiC→Ti 3 SiC 2
TiH 2 the decomposition process of (2) is carried out within the range of 620-720 ℃, because the activity of Ti obtained by decomposition is stronger, the Ti is easy to react with TiC and SiC at 1350 ℃ to generate Ti 3 SiC 2 . When the amount of added SiC is excessive, a (Ti 3 SiC 2 +sic). And Ti is 3 SiC 2 The SiC has good toughness and self-lubricating property, and has high heat conduction and hardness, and excellent high temperature resistance and wear resistance can be obtained by adjusting the proportion of the SiC and the SiC so as to meet the requirement of material selection of high-performance pistons.
Further preferably, the Ti as described in step (1) 3 SiC 2 And SiC accounts for 20-30% of the total volume of the slurry, ammonium polyacrylate accounts for 1-1.5% of the total volume of the slurry, and neutral silica sol accounts for 0.8-1% of the total volume of the slurry.
Further preferably, the low temperature drying condition in the step (3) is that the temperature is < -60 ℃ and the pressure is less than 10Pa.
Further preferably, the specific steps of the step (4) are as follows: firstly, putting a low-temperature dried green body into a vacuum sintering furnace, then pumping air in the sintering furnace, continuously introducing inert gas with the purity of 99.9% into the vacuum furnace when the numerical value of a vacuum meter is below minus 0.1MPa, keeping the air pressure at 0MPa, performing normal-pressure sintering, heating at the speed of 8-12 ℃/min, respectively preserving the temperature at 500 ℃ for 25-35 minutes, 1000 ℃ for 0.8-1.2 hours and 1350 ℃ for 1.8-2.2 hours, finally reducing the temperature to 300 ℃ at the cooling speed of 8-12 ℃/min, and then cooling the furnace to obtain (Ti) 3 SiC 2 +sic) porous ceramic skeleton.
It is further preferable that the mass ratio of the porous ceramic skeleton and the Al-Si alloy melt in the step (5) is 1:5-7.
The invention also protects the preparation methodTo obtain (Ti) suitable for pistons 3 SiC 2 +sic)/Al-Si composite.
The invention also protects the (Ti 3 SiC 2 Use of a +sic)/Al-Si composite in a piston. The (Ti 3 SiC 2 And processing the +SiC)/Al-Si composite material according to the size of the piston to obtain the high-performance piston.
Compared with the prior art, the invention has the beneficial effects that:
(1) Compared with the existing ceramic reinforced aluminum matrix composite, the invention benefits from various toughening mechanisms caused by radial lamellar structures, and can still maintain good strength and toughness under the condition of high ceramic content.
(2) The invention adopts an environment-friendly freezing casting method to construct the ceramic skeleton, and controls the lamellar morphology of the ceramic skeleton by adjusting factors such as additives, ceramic content, powder particle size, freezing temperature, sintering temperature and the like, thereby regulating and controlling the comprehensive performance of the composite material so as to meet the requirement of material selection under various working conditions.
Drawings
Fig. 1 is a process flow diagram of the present invention.
Fig. 2 is a schematic view of the refrigerating apparatus, in which (a) is a three-dimensional model view and (b) is a sectional view.
FIG. 3 is a cross-sectional profile of a ceramic backbone, where (a) is a macroscopic profile of a top cross-section, (b) is a microscopic profile of a top cross-section, (c) is a macroscopic profile of a head cross-section, and (d) is a microscopic profile of a head cross-section.
FIG. 4 is an XRD pattern of the layered porous ceramic skeleton obtained in example 1.
FIG. 5 shows the microstructure of the composite material obtained in example 1, wherein (a) is the microstructure of the top cross section and (b) is the microstructure of the head cross section.
FIG. 6 is a schematic of a mechanical test, wherein (a) is a schematic of a three-point bending test and (b) is a schematic of a fracture toughness test.
FIG. 7 is a schematic representation of a model of a high performance piston made using the present invention.
Reference numerals illustrate: 1. a metal plate; 2. alcohol; 3.a first insulating rod; 4. a copper cup; 5.a second insulating rod; 6. a ceramic sheet layer; 7. a metal sheet layer; 8. a top; 9. a head; 10. a ceramic/metal composite layer; 11. a metal layer; 12. a skirt.
Detailed Description
The present invention will be described in further detail with reference to examples. These examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. The experimental methods without specific conditions noted in the examples below are generally in accordance with conventional conditions in the art or in accordance with manufacturer's recommendations; the raw materials, reagents and the like used, unless otherwise specified, are considered to be commercially available through conventional markets and the like. Any insubstantial changes and substitutions made by those skilled in the art in light of the above teachings are intended to be within the scope of the invention as claimed.
The freezing mold used in the following embodiment comprises a metal disc 1 for containing a heat conducting medium, a copper cup 4 for conducting heat, and a first heat insulation rod 3 and a second heat insulation rod 5 which have heat insulation and shaping functions, wherein the bottom 4 of the copper cup is arranged in the metal disc 1, the second heat insulation rod 5 transversely penetrates through the copper cup 4 and the first heat insulation rod 3, the first heat insulation rod 3 is sleeved in the copper cup 4, and slurry is placed in a gap between the copper cup 4 and the first heat insulation rod 3 and between the copper cup 4 and the second heat insulation rod 5.
The heat insulating rod according to the present invention may be any rod that can provide heat insulation and molding effects, and the first heat insulating rod 3 and the second heat insulating rod 5 are preferably polytetrafluoroethylene rods in the following embodiments.
A heat conducting medium is provided in the metal disc 1, and the heat conducting medium is preferably alcohol 2 in the following embodiments. The metal plate 1 is made of stainless steel.
Before the freezing mould provided by the invention is used, the freezing mould is put into a freezer at the temperature of minus 35 ℃ for freezing for 30 minutes. The uniformly mixed slurry is then poured into the gap between the copper cup 4 and the first and second insulating bars 3 and 5. In the initial stage of freezing, the bottom and the outer ring of the copper cup simultaneously freeze the slurry at the bottom to form a compact reticular lamellar structure. As freezing proceeds, the middle and upper slurries are driven by a dual bottom-up and outside-in temperature gradient created by the copper cup to form a radial lamellar structure.
The materials used in the examples below include TiH 2 The specific information of the powder, tiC powder, siC powder, ammonium polyacrylate, neutral silica sol, deionized water and Al-Si alloy is shown in Table 1.
Table 1 specific information on materials used
Example 1:
a preparation method of a (TiC+Ti)/Mg layered composite material comprises the following steps:
(1) Mixing powder: weigh 100g of TiH 2 Pouring the powder, 60g TiC powder and 40g SiC powder into a ball mill tank, adding 174mL deionized water, 2g ammonium polyacrylate and 2g neutral silica sol, and then filling high-purity argon gas for ball milling for 2 hours to obtain the Ti-containing alloy 3 SiC 2 And a slurry of SiC.
(2) Freezing: the freezing mould is placed in a refrigerator at the temperature of minus 35 ℃ for 30 minutes, then the ball-milled slurry is poured into the refrigerator to freeze for 1 hour, and the ceramic layer and ice layer alternately arranged blocks are obtained after demoulding.
(3) And (3) drying at low temperature: the block is put into a freeze drying device and freeze dried under the environment of low temperature and low pressure (less than-65 ℃ and less than 10 Pa) for 48 hours.
(4) Sintering: firstly, putting the green compact into a vacuum sintering furnace, then, pumping air in the sintering furnace, continuously introducing argon with the purity of 99.9% into the vacuum furnace when the numerical value of a vacuum gauge is below-0.1 MPa, keeping the air pressure at 0MPa, and performing normal-pressure sintering. The sintering curve is: heating at a speed of 8 ℃/min, respectively preserving heat at 500 ℃ for 30 minutes, 1000 ℃ for 1 hour and 1350 ℃ for 1.2 hours, and finally cooling down to 200 ℃ at a cooling speed of 8 ℃/min, and then cooling with a furnace, thereby finally obtaining the porous ceramic skeleton with certain strength.
(5) Infiltration: the porous ceramic skeleton preheated at 300 ℃ is put into an H13 steel mould and then poured into 800g of refined porous ceramic skeletonThe composition is shown in Table I. Maintaining the pressure at 35MPa for 1min, and demolding to obtain (Ti) 3 SiC 2 +sic)/Al-Si composite.
Cutting and polishing the prepared ceramic skeleton and composite material, and performing morphology observation and performance test:
(1) Morphology observation: the microscopic morphology of the porous ceramic skeleton was observed using a SUPRA model 55 scanning electron microscope manufactured by ZEISS company, germany: the localized ordered and overall disordered dense morphology of the lamellae is observed in the cross section of the bottom of the ceramic skeleton (acting as top of the piston) (fig. 3.A and 3.b), while the radial lamellar structure is observed in the cross section of the middle of the ceramic skeleton (acting as head of the piston) (fig. 3.c), which is seen in the enlarged view of the part, in long range order (fig. 3. D); in order to quantify the ceramic content of different parts of the piston, image J software is used for counting the section microscopic images of the top and the head of the piston; phase composition analysis was performed on the ceramic skeleton using an X-ray diffractometer (XRD; bruker AXS) with a diffraction angle in the range of 30-80℃and a scanning speed of 5℃per minute. Results display (fig. 4): in the XRD pattern of the composite material, ti was found 3 SiC 2 、SiC、TiC、TiSi 3 And Ti is 5 SiC 3 Is shown to synthesize Ti in situ 3 SiC 2 And the prepared composite material has no other impurities; metallographic phase of the sample was observed using an XD30M series metallographic optical microscope manufactured by Ningbo Shun instruments Co., ltd.: wherein the white part is an Al-Si alloy sheet layer 6, and the black part is a ceramic sheet layer 7. The appearance of a locally ordered and overall disordered dense morphology of the lamellae was observed in the cross section of the bottom part of the composite (used as top part of the piston) (fig. 5.a), while the appearance of alternating metallic and ceramic layers was observed in the cross section of the middle part of the composite (used as head and skirt part of the piston) (fig. 5.B, enlarged in part).
(2) Mechanical properties: the bottom (used as the top of the piston) and the middle (used as the head and skirt of the piston) of the composite material were cut into samples of different sizes, respectively, using a wire electric discharge machine, with sample sizes of 4mm x 8mm and 3mm x 4mm x 20mm in compression and bending, respectively. The sample for fracture toughness test was a block with a size of 2mm by 4mm by 22mm, a notch was cut in the middle of the sample, a notch width of 0.3mm and a notch depth of 2mm (see FIG. 6). The composite material was subjected to compression, bending and fracture tests using an electronic universal material tester at a test temperature of 300 ℃.
Polishing and polishing all samples before testing, wherein the loading rate of the compression experiment is as follows: 0.5mm/min. The loading rates for bending and breaking are: 0.1mm/min, the experimental span was 10mm.
Compressive Strength (sigma) c ) And flexural Strength (sigma) f ) Calculated according to the following formula:
wherein P is IC For maximum applied load, A is the cross-sectional area of the compressed sample and S is the span; b is the sample width; h is the sample thickness.
The crack initiation toughness (K) of the material can be calculated according to the following formula IC ):
P IC Maximum load at break for the sample; a is the notch depth; s is a supporting span; b is the thickness of the test piece, and W is the width of the test piece.
(2) Friction and wear properties: the bottom (used as the top of the piston) and the middle (used as the head and skirt of the piston) of the composite material were cut into test pieces of different sizes, respectively, using a wire electric discharge machine, the test pieces being rectangular cubes of 10mm x 5 mm. The test temperature was 300 ℃, and the test surface was a cross section of the top and a longitudinal section of the head, respectively. The applied load in the experiment was 10N, and the linear reciprocating distance and speed were 5mm and 8mm/s, respectively.
The wear rate can be calculated by the following formula:
wherein A is the wear cross-sectional area, L is the wear length, F is the load, and S is the sliding distance.
The results of the tests for ceramic content, high temperature compressive strength, high temperature flexural strength, fracture toughness and high temperature wear rate of the composite are shown in Table 2.
Example 2
The same as in example 1, except that:
changing the step (1) into: weigh 91.84g of TiH 2 Pouring the powder, 55g TiC powder and 46.7g SiC powder into a ball mill tank, adding 174mL deionized water, 2g ammonium polyacrylate and 2g neutral silica sol, and then filling high-purity argon gas for ball milling for 2 hours to obtain the Ti-containing alloy 3 SiC 2 And a slurry of SiC.
In accordance with the test method of example 1, the prepared composite material was cut and polished for morphology observation and mechanical property test. The results of the tests for the ceramic content, high temperature compressive strength, high temperature flexural strength, fracture toughness and high temperature wear rate of this example are shown in Table 2.
Example 3
The same as in example 1, except that:
changing the step (1) into: weigh 85.7g of TiH 2 Pouring the powder, 51.43g TiC powder and 54.2g SiC powder into a ball mill tank, adding 174mL deionized water, 2g ammonium polyacrylate and 2g neutral silica sol, and then filling high-purity argon gas for ball milling for 2 hours to obtain the Ti-containing alloy 3 SiC 2 And a slurry of SiC.
In accordance with the test method of example 1, the prepared composite material was cut and polished for morphology observation and mechanical property test. The results of the tests for the ceramic content, high temperature compressive strength, high temperature flexural strength, fracture toughness and high temperature wear rate of this example are shown in Table 2.
Example 4
The same as in example 1, except that:
changing the step (1) into: weigh 100g of TiH 2 Pouring the powder, 60g TiC powder and 40g SiC powder into a ball mill tank, adding 100mL deionized water, 2g ammonium polyacrylate and 2g neutral silica sol, and then filling high-purity argon gas for ball milling for 2 hours to obtain the Ti-containing alloy 3 SiC 2 And a slurry of SiC.
In accordance with the test method of example 1, the prepared composite material was cut and polished for morphology observation and mechanical property test. The results of the tests for the ceramic content, high temperature compressive strength, high temperature flexural strength, fracture toughness and high temperature wear rate of this example are shown in Table 2.
Example 5
The same as in example 1, except that:
(2) Freezing: placing the freezing mould in a freezing container at the temperature of minus 30 ℃, then pouring slurry into the freezing container for freezing for 1.5 hours, and demoulding to obtain blocks with alternately arranged ceramic layers and ice layers;
(3) And (3) drying at low temperature: drying at low temperature for 24 hours to obtain a dried green body;
(4) Firstly, putting a low-temperature dried green body into a vacuum sintering furnace, then pumping air in the sintering furnace, continuously introducing inert gas with the purity of 99.9% into the vacuum furnace when the numerical value of a vacuum meter is below minus 0.1MPa, keeping the air pressure at 0MPa, performing normal-pressure sintering, heating at the speed of 8 ℃/min, respectively preserving heat at 500 ℃ for 25 minutes, 1000 ℃ for 0.8 hours, and 1350 ℃ for 1.8 hours, finally reducing the temperature to 300 ℃ at the cooling speed of 8 ℃/min, and cooling along with the furnace to obtain (Ti) 3 SiC 2 +sic) porous ceramic skeleton;
(5) Infiltration: firstly placing a porous ceramic skeleton preheated at 280 ℃ into an H13 steel mould, then pouring a refined Al-Si alloy melt, maintaining the pressure for 1.2min under the pressure of 32MPa, and demoulding to obtain the (Ti) with a radial lamellar structure 3 SiC 2 +SiC)/Al-Si composite material, porous ceramic skeleton and Al-Si alloyThe mass ratio of the gold melt is 1:5.
Example 6
The same as in example 1, except that:
(2) Freezing: placing the freezing mould in a freezing container at the temperature of minus 35 ℃, then pouring slurry into the freezing container for freezing for 1.0 hour, and demoulding to obtain blocks with alternately arranged ceramic layers and ice layers;
(3) And (3) drying at low temperature: drying at low temperature for 48 hours to obtain a dried green body;
(4) Firstly, putting a low-temperature dried green body into a vacuum sintering furnace, then pumping air in the sintering furnace, continuously introducing inert gas with the purity of 99.9% into the vacuum furnace when the numerical value of a vacuum meter is below minus 0.1MPa, keeping the air pressure at 0MPa, performing normal-pressure sintering, heating at the speed of 12 ℃/min, respectively preserving the temperature at 500 ℃ for 35 minutes, 1000 ℃ for 1.2 hours and 1350 ℃ for 2.2 hours, and finally cooling the green body along with the furnace after the temperature is reduced to 300 ℃ at the cooling speed of 12 ℃/min to obtain (Ti) 3 SiC 2 +sic) porous ceramic skeleton;
(5) Infiltration: firstly placing a porous ceramic skeleton preheated at 320 ℃ into a mould, then pouring refined Al-Si alloy melt, maintaining the pressure at 37MPa for 0.8min, and demoulding to obtain the (Ti) with radial lamellar structure 3 SiC 2 The mass ratio of the porous ceramic skeleton to the Al-Si alloy melt of the +SiC)/Al-Si composite material is 1:5.
Comparative example 1
The Al-Si alloy is treated, comprising the following steps:
800g of Al-Si alloy was prepared according to the composition of Table 1, and the alloy was left to stand for 10 minutes after refining and degassing. Then pouring the mixture into an H13 steel die, maintaining the pressure for 1min under the pressure of 35MPa, and demoulding to obtain the extrusion cast Al-Si alloy.
In accordance with the test method of example 1, the prepared composite material was cut and polished for morphology observation and mechanical property test. The results of the tests for the ceramic content, high temperature compressive strength, high temperature flexural strength, fracture toughness and high temperature wear rate of this comparative example are shown in Table 2.
Comparative example 2
Non-lamellar (T)i 3 SiC 2 The preparation method of the +SiC)/Al-Si composite material comprises the following steps:
weigh 100g of TiH 2 The powder, 60g TiC powder and 40g SiC powder are poured into a ball mill pot for ball milling for 2 hours. And then pressing the mixed powder, and sintering, wherein the mixing and sintering of the powder are carried out under the protection of high-purity argon. Preheating the prefabricated block at 300 ℃ for 30 minutes, adding the prefabricated block into 800g of Al-Si alloy melt, preserving heat, stirring to enable the prefabricated block to be melted and dispersed in the melt, and then refining, degassing, preserving heat and standing. Finally pouring into an H13 steel mold, maintaining the pressure for 1min under the pressure of 35MPa, and demoulding to obtain the non-lamellar (Ti) 3 SiC 2 +sic)/Al-Si composite.
In accordance with the test method of example 1, the prepared composite material was cut and polished for morphology observation and mechanical property test. The results of the tests for the ceramic content, high temperature compressive strength, high temperature flexural strength, fracture toughness and high temperature wear rate of this comparative example are shown in Table 2.
TABLE 2 Performance test results
The materials obtained in comparative examples 1 and 2 were not significantly different in performance at the upper, middle and lower positions, but were more uniform in structure at the middle, so that the middle was selected for performance testing. From the test results of the examples, the ceramic content of the top part is higher than that of the head part. The high ceramic content top can withstand higher temperatures, while the low ceramic content head can provide good toughness, which is advantageous for the piston of the present invention to accommodate more complex operating conditions. The high ceramic content also contributes to the high temperature compressive strength of the composite material, e.g. as high as 865MPa on top of example 4, twice that of the matrix (comparative example 1), compared to the non-layered (Ti 3 SiC 2 The +SiC)/Al-Si composite material is improved by 41 percent. From example 1 to example 3, the high temperature compressive strength of the same location gradually increased, since more SiC remained increased the high temperature compressive strength of the composite. However, too much SiC will cause multiplexingThe high temperature bending strength of the composite material is reduced, the optimal bending strength is 553Mpa, and the high temperature bending strength is improved by 70 percent and 30 percent compared with comparative example 1 and comparative example 2 respectively. By regulating and controlling the ceramic content of the composite material, the composite material has good fracture toughness, and the optimal fracture toughness is 18.15MPa m 1/2 The improvement is 41% compared with comparative example 2. In the aspect of high-temperature frictional wear, the high-temperature wear rate is obviously reduced along with the increase of the ceramic content, and the minimum wear rate is 0.98x10 -4 mm 3 And Nm, the wear resistance of the composite material is obviously improved. From the test results of examples 1, 5 and 6, the fluctuation of test parameters such as freezing temperature, low temperature drying time, sintering curve and pressure impregnation condition affect the performance of the material, but the overall effect is not great.
A schematic diagram of a piston prepared by using the composite material is shown in FIG. 7, the top 8 with high ceramic content has excellent compressive strength and lower thermal expansion rate when bearing high temperature, the ceramic/metal composite layer 10 on the outer layers of the head 9 and the skirt 12 can provide good wear resistance, and the Al-Si alloy layer 11 inside ensures good toughness of the piston and prevents fracture failure in working.
In summary, the invention benefits from the multiple toughening mechanisms caused by the lamellar structure, such as multi-crack propagation, crack passivation and deflection, and the extraction of the metal layer and the ceramic sheet, and the Ti generated by the regulation reaction 3 SiC 2 And TiC, the invention has good high-temperature compressive strength, high-temperature bending strength, fracture toughness and high-temperature wear resistance. Compared with an Al-Si matrix, the high-temperature performance of the composite material is greatly improved, and the composite material can be used for preparing high-performance piston members by regulating and controlling the ceramic content and lamellar arrangement of different parts.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that the above-mentioned preferred embodiment should not be construed as limiting the invention, and the scope of the invention should be defined by the appended claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and such modifications and adaptations are intended to be comprehended within the scope of the invention.

Claims (10)

1. The freezing mold is characterized by comprising a metal disc, a copper cup, a first heat insulation rod and a second heat insulation rod, wherein the bottom of the copper cup is arranged in the metal disc, a heat conducting medium is arranged in the metal disc, the second heat insulation rod transversely penetrates through the copper cup and the first heat insulation rod, the first heat insulation rod is sleeved in the copper cup, and slurry is placed in a gap between the copper cup and the first heat insulation rod and between the copper cup and the second heat insulation rod.
2. The freezing mold of claim 1, wherein the metal plate is made of stainless steel, and the heat-conducting medium is alcohol.
3.A piston (Ti 3 SiC 2 The preparation method of the +SiC)/Al-Si composite material is characterized by comprising the following steps: preparation of a composition having a radial lamellar structure (Ti using the freezing mold according to claim 1 or 2 3 SiC 2 +SiC) porous ceramic skeleton, and completely immersing Al-Si alloy into the porous ceramic skeleton by extrusion infiltration to obtain (Ti) 3 SiC 2 +sic)/Al-Si composite.
4. A method of preparation according to claim 3, comprising the specific steps of:
(1) Mixing powder: the mass ratio is 5:3:2-2.85 TiH 2 Pouring TiC and SiC into a container, adding water, ammonium polyacrylate and neutral silica sol, charging high-purity argon, and ball milling for 1-3h to obtain the Ti-containing alloy 3 SiC 2 A slurry in which particles of +sic are uniformly dispersed;
(2) Freezing: placing the unidirectional freezing mold in a freezing container with the temperature of minus 30 ℃ to minus 35 ℃, pouring the slurry obtained in the step (1) into the container for freezing for 1.0 to 1.5 hours, and demolding to obtain blocks with alternately arranged ceramic layers and ice layers;
(3) And (3) drying at low temperature: drying at low temperature in a low-temperature dryer for 24-48 hours to obtain a dried green body;
(4) Sintering: sintering the green body under the protection of inert gas to obtain a layered porous ceramic skeleton;
(5) Infiltration: firstly placing a porous ceramic skeleton preheated at 280-320 ℃ into a mould, then pouring refined Al-Si alloy melt, maintaining the pressure for 0.8-1.2min under the pressure of 32-37MPa, and demoulding to obtain the (Ti) with radial lamellar structure 3 SiC 2 +sic)/Al-Si composite.
5. The method according to claim 4, wherein the Ti in the step (1) 3 SiC 2 +SiC accounts for 20 to 30 percent of the total volume of the slurry, ammonium polyacrylate accounts for 1 to 1.5 percent of the total volume of the slurry, and neutral silica sol accounts for 0.8 to 1 percent of the total volume of the slurry.
6. The process according to claim 4, wherein the low-temperature drying in step (3) is carried out at a temperature of < -60℃and a pressure of < 10Pa.
7. The method according to claim 4, wherein the specific steps of step (4) are: firstly, putting a low-temperature dried green body into a vacuum sintering furnace, then pumping air in the sintering furnace, continuously introducing inert gas with the purity of 99.9% into the vacuum furnace when the numerical value of a vacuum meter is below minus 0.1MPa, keeping the air pressure at 0MPa, performing normal-pressure sintering, heating at the speed of 8-12 ℃/min, respectively preserving the temperature at 500 ℃ for 25-35 minutes, 1000 ℃ for 0.8-1.2 hours and 1350 ℃ for 1.8-2.2 hours, finally reducing the temperature to 300 ℃ at the cooling speed of 8-12 ℃/min, and then cooling the furnace to obtain (Ti) 3 SiC 2 +sic) porous ceramic skeleton.
8. The method according to claim 4, wherein the mass ratio of the porous ceramic skeleton to the Al-Si alloy melt in the step (5) is 1:5-7.
9. The process of claim 3 or 4, wherein the piston (Ti 3 SiC 2 +sic)/Al-Si composite.
10. (Ti of claim 9 3 SiC 2 Use of a +sic)/Al-Si composite in a piston.
CN202311194296.0A 2023-09-15 2023-09-15 A (T) suitable for a pistoni 3 SiC 2 +SiC)/Al-Si composite material and preparation method thereof Pending CN117444179A (en)

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