CN114000069B - Preparation method of continuous SiC fiber reinforced metal matrix composite lattice structure - Google Patents

Abstract

The invention relates to a method for preparing a lattice structure of a continuous SiC fiber reinforced metal matrix composite material. Polymethyl methacrylate (PMMA) can be softened, melted-solidified at medium and low temperatures (~270° C.) ～400℃) can be completely cracked into gas, soak SiCf-metal precursor ribbons in PMMA melt, and obtain uniformly arranged precursor ribbons after solidification. The precursor ribbons are alternately arranged and then heated and pressurized, so that the precursor ribbons are in contact with each other And the relative position is fixed under the action of pressure, further heating makes PMMA cracking and gasifying, and the multi-void structure is conducive to the volatilization of the cracking gas, and then the temperature is raised to a certain temperature, and the pressure is applied to make the precursor filaments diffuse and connect to each other to form a whole, and a lattice is obtained. structure. The lattice structure prepared by the method has uniform and controllable spacing of the precursor wires, and the relative angle of the interlayer precursor wires can be adjusted in real time according to the position, which can meet more design structure requirements.

Description

A kind of preparation method of continuous SiC fiber reinforced metal matrix composite lattice structure

technical field

The invention belongs to the technical field of material preparation, and in particular relates to a preparation method of a lattice structure of a continuous SiC fiber reinforced metal matrix composite material.

Background technique

Lattice material is a new type of porous material with regular pore shape and periodic arrangement of holes. The biggest difference from traditional materials is that it has ever-changing ordered microstructure and high porosity, as well as light weight and high strength. , efficient heat dissipation, absorption of electromagnetic waves and sound, anti-explosive shock and other excellent properties, under the same weight, it has better mechanical properties than metal foam with disordered microstructure, so it has great application potential in many fields, such as aviation Aerospace, transportation, weapons and equipment, construction, etc. Commonly used materials for lattice materials include metal materials, ceramic materials and carbon fiber reinforced resin matrix composite materials. Metal materials have good formability but cannot be used at higher temperatures. Carbon fiber reinforced resin matrix composites are also limited by service temperature and their compression resistance is poor. Although ceramic materials can be used at high temperatures, they have poor formability. , especially the connections between "dots".

Therefore, in order to meet the needs of higher temperature use and better formability, it is necessary to make good use of the characteristics of metal formability and high temperature resistance of ceramics. Ceramic/metal composite materials have a good design space. Among them, continuous monofilament SiC fiber ceramics The fiber has excellent tensile, compressive and shear strength at room temperature, and is suitable for use as a reinforcement for metal matrix composites. It has a large diameter, good operability, and is easy to form. Titanium alloys also have excellent medium and high temperature properties. , good formability and good chemical compatibility with SiC fibers, so the lattice structure of continuous SiC fiber reinforced titanium matrix composites has good application potential. At present, the process of preparing the lattice structure of continuous SiC fiber reinforced titanium matrix composites is mainly by designing an auxiliary mold for the arrangement of precursor wires, and vacuum hot pressing after laying the precursor wires. In this method, the required mold is relatively complicated, and each layer of precursor wire has only a fixed relative angle with the adjacent precursor wire of the upper and lower layers.

SUMMARY OF THE INVENTION

In order to overcome the disadvantages of complex precursor wire laying auxiliary mold and relatively single distribution angle of precursor wire required for the preparation of continuous SiC fiber-reinforced metal matrix composite lattice structure, the purpose of the present invention is to provide an auxiliary mold that can simplify the preparation process. , Pioneering wire arrangement angle adjustable, variable SiC fiber reinforced metal matrix composite material lattice structure preparation process.

In order to achieve the above object, the present invention adopts the following technical solutions:

A preparation method of continuous SiC fiber reinforced metal matrix composite material lattice structure, characterized in that, the preparation process is carried out according to the following steps:

Step 1, cutting the continuous SiC _f -metal precursor wire to obtain a precursor ribbon composed of a group of parallel arranged precursor wires with uniform _spacing . The relative spacing of the precursor wires is fixed, and then the precursor ribbons are obtained by cutting along the cylindrical bus bar, which can improve the uniformity and efficiency. The center distance between adjacent precursor wires can be controlled between 0.2 mm and 3 mm by controlling the winding pitch according to design requirements, and can be adjusted according to specific design requirements. The continuous SiC _f -metal precursor wire is a SiC fiber with a coating of metal or its alloy with a thickness of 20 μm to 100 μm on the surface. The metal may be selected from titanium, copper, iron, nickel, aluminum, magnesium or tungsten, among others.

Step 2, soak the precursor ribbon prepared in step 1 with polymethyl methacrylate melt and solidify to obtain a single-layer precursor ribbon; specifically, the precursor ribbon in step 1 can be placed in a groove with a predetermined depth inside and fixed; polymethyl methacrylate (PMMA) is heated to a molten state and poured into the groove until the pioneer ribbon is completely immersed, and the polymethyl methacrylate solidifies after cooling to fix the relative position of the pioneer silk, The single-layer precursor silk sheet was prepared. When the continuous SiC _f -metal precursor wire is a SiC fiber with a diameter of 100 μm with a coating of 20 μm to 100 μm thick metal or its alloy on the surface, the predetermined depth of the groove may be 0.15 to 0.5 mm.

Step 3, repeating Step 2 or using multiple grooves to simultaneously prepare the precursor silk sheets to prepare multiple pioneer silk sheets;

Step 4. Stack the precursor wire plates prepared in step 3, and the precursor wires in the adjacent two layers of precursor wire plates are arranged at a certain angle; the angle is generally 20° to 90°, depending on design requirements.

Step 5. Place the stacking precursor wire plates in step 4 in a vacuum hot-pressing furnace, apply a pressure of 0.01 MPa to 0.5 MPa, evacuate to 10 ^-2 Pa, and heat up to 180 ℃ to 200 ℃, and the heating time is 2h ~ 3h, PMMA will soften and melt during the heating process, keep the heat preservation and pressure for 1h ~ 3h, the pressure will make the SiC _f -metal precursor wires between the layers reach the state of mutual contact; increase the temperature to 270℃ ~ 400℃, keep the heat preservation and pressure for 4h ~6h, at this temperature, PMMA is completely cracked into gas; then it is heated to a temperature of 0.4 to 0.8 times the melting point of the metal (when the metal is titanium, 700 ° C ~ 1000 ° C (determined by the titanium alloy grade)), pressurized to 0.5 MPa ~ 40MPa, heat preservation and pressure for 2h ~ 10h, so that the mutual diffusion connection between the contacting precursor filaments becomes a whole, and the furnace is cooled to less than 200 ℃, and then the pressure is relieved and taken out, and the continuous SiC fiber reinforced metal matrix composite material lattice structure is obtained.

The advantages of the present invention: (1) the preparation process of the present invention does not require a complex precursor wire laying die, and at the same time, the spacing of the precursor wires can be uniform and controllable, and the PMMA has good light transmittance, which can be visually inspected and screened. The uniformity and defects of the silk plate arrangement; (2) the large number of pores in the lattice structure of the metal matrix composite material facilitates the volatilization of the gas after the PMMA cracking; Due to the limitation of the angle, the arrangement angle of the interlayer precursor wires is more flexible, which can more flexibly meet the design requirements; (4) the outermost layer of the lattice structure of the metal matrix composite material obtained by this method is metal or its alloy, which is convenient for welding and welding. For other component/structural connections, the connection position has the advantages of high temperature resistance and high strength.

Description of drawings

Fig. 1 is the preparation and stacking process schematic diagram of the pioneer silk plate of the present invention;

FIG. 2 is a schematic diagram of a lattice structure prepared by the method of the present invention.

Detailed ways

In order to understand the objectives, technical solutions and advantages of the present invention more clearly, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

The present invention provides a method for preparing a continuous SiC fiber reinforced metal matrix composite material lattice structure. .

Put double-sided tape on the busbar direction of the outer cylindrical surface outside the cylindrical tooling, and place one end of the SiC _f -TC17 precursor wire (a SiC fiber with a diameter of 100 μm with a TC17 titanium alloy coating of 25 μm on the surface) perpendicular to the double-sided The glue is fixed on the surface of the cylinder tooling, and it is rotated clockwise along the central axis of the cylinder tooling. The diameter and height of the cylinder can be adjusted. The circumference of the cylinder is the length of the SiC _f -TC17 precursor ribbon, and the precursor wire is wound. The spacing is set to 0.5mm, and the SiC _f -TC17 precursor wire wound to the specified width is fixed by double-sided tape, as shown in Figure 1(a). Cut all the wound SiC _f -TC17 precursor wires along the direction of the double-sided tape (i.e., the busbar direction of the outer cylindrical surface) to obtain SiC _f -TC17 precursor ribbons, in this way, the precursors of SiC _f -TC17 precursor ribbons The filaments are evenly distributed and the efficiency is high.

Place the precursor ribbon in a groove with a depth of 0.3mm and fix it, as shown in Figure 1(b); heat the PMMA to 200 °C to melt, pour the melt into the groove until the precursor ribbon is completely immersed, and the PMMA solidifies after cooling The relative position of the SiC _f -TC17 precursor wire was fixed to obtain a single-layer SiC _f -TC17 precursor wire plate;

Repeat the previous step or use multiple grooves to prepare multiple SiC _f -TC17 precursor silk sheets.

The SiC _f -TC17 precursor wire plates were stacked in a vacuum hot pressing furnace, and the laying angles were alternately distributed at 0°/45°/90°, as shown in Figure 1(c). Apply a load of 0.1 MPa for pre-pressurization, evacuate to 10 ^-2 Pa, heat up to 200 °C, heat up for 2 hours, and keep the pressure for 3 hours. During the heating process, PMMA begins to soften and melt. Under the action of pressure, the interlayer is formed. The SiC _f -TC17 precursor filaments reached a state of contact, that is, the relative positions between the precursor filaments have been fixed; the temperature was raised to 400 °C, and the temperature was maintained for 6 hours. At this temperature, PMMA was completely decomposed into gas, and only the position was fixed. Then the temperature was raised to 900°C, pressurized to 10MPa, and kept under pressure for 5h, so that the contacting precursor wires were connected to each other by diffusion to form a whole. The lattice structure of SiC fiber reinforced TC17 composite is shown in Figure 2.

Although the TC17 titanium alloy is used as an example for the above description, it can be replaced by titanium or other titanium alloys, or even replaced by other metals or their alloys. In this case, the contacting precursor wires are interdiffused The temperature required to form the whole is generally 0.4 to 0.8 times the melting point of the corresponding metal or its alloy.

The present invention utilizes the characteristics that polymethyl methacrylate (PMMA) can be softened, melted and solidified at medium and low temperature (~270°C) and can be completely cracked into gas at medium temperature (~400°C), and the SiCf is soaked in PMMA melt. -Metal precursor ribbons, uniformly arranged precursor ribbons can be obtained after curing. The precursor ribbons are alternately arranged and then heated and pressurized, so that the precursor ribbons are in contact with each other and their relative positions are fixed under the action of pressure. Further heating causes the PMMA to crack and gasify. The multi-empty structure is conducive to the volatilization of the pyrolysis gas, and then the temperature is raised to a certain temperature, and the pressure is applied to make the precursor filaments diffuse and connect to each other to form a whole to obtain a lattice structure. The lattice structure prepared by the method has uniform and controllable spacing of the precursor wires, and the relative angle of the interlayer precursor wires can be adjusted in real time according to the position, which can meet more design structure requirements.

Claims (9)

1. a preparation method of continuous SiC fiber-reinforced metal matrix composite lattice structure, comprising the following steps: Step 1, cutting the continuous SiC _f -metal precursor wire to obtain a precursor ribbon composed of a group of precursor wires arranged in parallel and evenly spaced; Step 2, soak the precursor ribbon obtained in step 1 with the polymethyl methacrylate melt and solidify to obtain a single-layer precursor wire plate; Step 3, repeating Step 2 to prepare a plurality of pioneer silk plates; Step 4, stacking the precursor wire plates prepared in step 3, and the precursor wires in the adjacent two layers of precursor wire plates are arranged at a certain angle; Step 5. Place the stacked precursor wire plates in step 4 in a vacuum hot pressing furnace, apply a pressure of 0.01MPa to 0.5MPa, and heat up to 180°C to 200°C, the heating time is more than 2h, and the temperature is maintained for more than 1h. ; then heat up to 270 ℃ ~ 400 ℃, heat preservation and pressure for more than 4h; then heat up to a temperature of 0.4 to 0.8 times the melting point of the metal, pressurize to 0.5MPa ~ 40MPa, heat preservation and pressure for 2h ~ 10h; furnace cool to below 200 After ℃, the pressure is relieved and taken out, and the lattice structure of the continuous SiC fiber reinforced metal matrix composite material is obtained. 2 . The method according to claim 1 , wherein the continuous SiC _f -metal precursor wire is a SiC fiber with a coating of 20 μm to 100 μm thick metal or its alloy on the surface. 3 . 3. The method of claim 2, wherein the metal is selected from titanium, copper, iron, nickel, aluminum, magnesium or tungsten. 4. The method according to claim 1, wherein said cutting the continuous SiC _f -metal precursor wire to obtain a precursor ribbon consisting of a group of parallel and uniformly arranged precursor wires comprises winding the continuous SiC _f -metal precursor wire on a circle. On the outside of the cylinder, the relative spacing of the precursor wires is fixed, and then the precursor ribbons are obtained by cutting along the generatrix of the cylinder. 5. according to the method described in claim 1, wherein the pioneer ribbon that obtains single-layer pioneer silk plate after soaking step 1 with polymethyl methacrylate melt solution is solidified comprises that the pioneer ribbon in step 1 is placed in the depth of Put it in the groove of a predetermined depth and fix it; after heating the polymethyl methacrylate to a molten state, pour it into the groove until the precursor ribbon is completely submerged, and after cooling, the polymethyl methacrylate solidifies to make the relative position of the precursor wire. fixed to obtain the single-layer precursor silk sheet. 6. The method according to claim 5, wherein the continuous SiC _f -metal precursor wire is a SiC fiber with a diameter of 100 μm having a coating of a metal or its alloy with a thickness of 20 μm to 100 μm on the surface, and the grooves are predetermined. The depth is 0.15 to 0.5 mm. 7. The method according to claim 1, wherein the center distance between adjacent precursor wires is 0.2mm˜3mm. 8. The method according to claim 1, wherein the angle between the precursor wires in the two adjacent layers of precursor wire sheets is 20°˜90°. 9. The method according to claim 1, wherein the heating time for heating to 180°C～200°C is 2h～3h, the heat preservation and pressure keeping time is 1h～3h, and the heat preservation and pressure keeping time at 270°C～400°C is 4h～6h.

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