A casting method for TiB2 particle aluminum matrix ceramic composite

Abstract

The application discloses a casting forming method of TiB2 particle aluminum-based ceramic composite material, which comprises the following steps: step 1: alloy melt refining, adopting CoverAL1565 solvent as alloy melt slagging agent, and performing twice slagging refining on the alloy melt, the solvent adding amount is 0.1-0.9% of the total amount of the alloy; step 2: designing a runner, widening the inner runner of the runner; step 3: pouring after attaching a casting sample and a casting skin layout, the casting sample adopts bottom layout, the casting skin adopts cold iron layout, the cold iron layout is aluminum cold iron+iron cold iron collocation, wherein aluminum cold iron is used for chilling at other parts of the casting skin, and iron cold iron is used for chilling at the position directly opposite to the runner of the casting skin; step 4: sampling analysis, sampling at three positions of the upper, middle and lower of the gap runner is adopted to perform alloy chemical component analysis; the application proposes a new casting forming process method from aspects of alloy smelting, alloy chemical component sampling and casting pouring, and realizes high-quality forming of the alloy material casting.

Description

Technical Field

[0001] This invention belongs to the field of casting and molding technology, and specifically relates to a casting and molding method for TiB2 particle aluminum-based ceramic composite materials. Background Technology

[0002] TiB2 particle aluminum-based ceramic composites have attracted widespread attention in aerospace, shipbuilding, weaponry, and automotive parts industries due to their high strength and low coefficient of thermal expansion. However, the introduction of TiB2 ceramic particles alters the solidification characteristics of aluminum-based alloys. The alloy's melting process, molten metal flowability, and solidification rate differ significantly from Al-Si alloys such as ZL101A and ZL114A, leading to casting defects such as under-casting, shrinkage cavities, porosity, and segregation during the casting process.

[0003] Currently, most sand casting processes for TiB2 granular aluminum-based ceramic composites employ pressure casting to improve the density of the castings. However, due to limited references and low process maturity, the mechanical properties, internal quality, and chemical composition of the cast parts differ significantly from actual requirements, hindering their widespread application in engineering and impeding further alloy development. The existing technologies suffer from the following problems: 1) Melt treatment primarily utilizes ZL101A and ZL114A melt processes. The melt flow of TiB2 granular aluminum-based ceramic composites differs significantly from Al-Si alloys like ZL101A and ZL114A, resulting in poor melt quality when refined using these alloys; 2) Existing gating spacing does not meet the alloy's filling requirements. TiB2 granular aluminum-based ceramic composites exhibit poor alloy flow and rapid crystallization. Excessive gating spacing can lead to under-compensation in castings, while denser gating increases manufacturing costs and makes gating separation difficult; 3) Alloying… The sampling method for chemical composition analysis involves casting a spectroscopic alloy ingot and then taking powder samples for analysis. This ingot sampling method is prone to compositional deviation. In conventional spectroscopic alloy ingot sampling, the molten metal is located on the surface of the melt, and Ti element is prone to precipitation and segregation, resulting in large deviations in the compositional analysis results and misjudging the casting as scrap. 4) The attached casting sample is located at the top of the sprue, and its performance is poor. Due to the tendency of Ti element to precipitate and segregate, the Ti element composition changes when the molten metal fills to the top of the casting, resulting in poor test bar performance. 5) The casting chill and gating layout adopts the conventional Al-Si alloy forming method, and the chill process is difficult to ensure forming quality. Since TiB2 particle aluminum-based ceramic composite materials are quite sensitive to chill material, it is difficult to establish an ideal solidification trend by using only iron or aluminum chills, resulting in a low casting qualification rate.

[0004] CN115044809B discloses a casting aluminum-silicon alloy and its preparation method, as well as an aluminum-silicon alloy for aerospace or automotive castings. The method involves heating aluminum ingots to 900-1050℃ in a pit-type resistance furnace until completely melted. A graphite bell jar is then pressed into the ingot, and after the reaction shows signs of ignition, the bell jar is removed to allow for a direct self-propagating reaction of the melt for 5-8 minutes. After the reaction, C2Cl6 is added for refining, followed by stirring and settling for 5-20 minutes. The slag is then removed, and this process of stirring, settling, and slag removal is repeated 1-2 times. The resulting melt is then poured into a preheated steel mold at 750-900℃ to obtain a high-volume-fraction Al-TiB2 pure-phase master alloy, i.e., a TiB2 / Al composite material. This method optimizes the aluminum-silicon alloy composition, improving the high cost problem caused by impurities in high-mechanical-performance alloys, thereby expanding the application fields of high-strength and high-toughness aluminum-silicon alloys. However, differences still exist compared to actual needs. Summary of the Invention

[0005] To address the aforementioned problems, this invention aims to provide a casting method for TiB2 particle aluminum-based ceramic composite materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a casting molding method for TiB2 particle aluminum-based ceramic composite materials, comprising the following steps:

[0007] Step 1: Refining of alloy melt. CoverAL1565 solvent is used as slagging agent for alloy melt, and the alloy melt is refined twice. The amount of solvent added is 0.1% to 0.9% of the total alloy volume.

[0008] Step 2: Design the gating system and widen the ingate.

[0009] Step 3: After the attached sample and the skin of the casting are laid out, the casting is poured. The attached sample adopts the bottom layout, and the skin of the casting adopts the chill layout. The chill layout is a combination of aluminum chill and iron chill. Aluminum chill is used for rapid cooling in other parts of the skin of the casting, and iron chill is used for rapid cooling in the part directly opposite the gating of the skin of the casting.

[0010] Step 4: Sampling and analysis, using samples taken from the top, middle and bottom of the sprue for alloy chemical composition analysis;

[0011] In step 1, the specific process of the two slag refining processes is as follows: the temperature of the first slag refining is 755-765℃, and the amount of CoverAL1565 solvent added is 0.75-0.9% of the total alloy volume; the temperature of the second slag refining is 730-740℃, and the amount of CoverAL1565 solvent added is 0.1-0.2% of the total alloy volume.

[0012] After two slag-forming processes, an argon rotary jet method is used, with a refining temperature of 725–730℃ and a refining time of 20–25 minutes. After refining, the mixture is allowed to stand for 8–10 minutes before slag removal and casting.

[0013] In step 2, the designed gating gap spacing is 80-100mm, the width of the ingate for a vertical gating channel with a diameter of 60mm is 36-40mm, and the width of the ingate for a vertical gating channel with a diameter of 75mm is 48-50mm.

[0014] In step 3, the layout of the attached casting sample is as follows: the position is located between the two horizontal runners of the bottom plate, the length is 160-180mm, the riser height is 20-30mm, the riser draft angle is 8-10°, and the chill is an aluminum-clad chill on both sides with a thickness of 1-1.5 times the thickness of the sample.

[0015] In step 3, the layout of the casting skin is as follows: iron chills are used directly opposite the gating, with a thickness of 1.5 to 2 times the thickness of the casting skin; aluminum chills are used for other skin parts, with a thickness of 0.5 to 0.8 times the thickness of the casting skin, but not less than 6 mm.

[0016] The pressure parameters for the casting process in step 3 are as follows: liquid lifting / filling speed is 70-90 mm / s, liquid lifting pressure is 45-90 kPa, filling pressure is 75-125 kPa, crystallization pressurization speed is 2.0 kPa / s, and casting temperature is 735-740℃.

[0017] In step 4, the alloy chemical composition is sampled as follows: samples are taken from three locations—upper, middle, and lower—at the contact section between the gating system and the casting body, mixed, and then sent for testing.

[0018] The three sampling locations are the top, middle, and bottom of the sprue. The top sampling location is 20-60mm away from the top plane, the bottom sampling location is 50-80mm away from the bottom plane, and the middle sampling location is 20mm away from the center line. All three sampling locations are at least 5mm away from the edge of the sprue.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. Using CoverAL1565 solvent as a slag-forming agent for alloy melts and reasonably controlling the solvent's smelting process parameters resulted in good alloy melt treatment quality.

[0021] 2. By widening the gating system and setting reasonable pouring parameters, the casting qualification rate is high, and the ability to guide engineering applications is strong.

[0022] 3. The casting specimens are arranged at the bottom and the casting skin is made of chilled iron, resulting in specimens with good mechanical properties.

[0023] 4. The sampling location of the alloy chemical analysis sample is reasonably selected, and its elemental composition is close to the actual value of the casting, reducing the scrapping of castings due to unqualified alloy composition. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the slit gating system for sampling the chemical composition of the alloy in this invention;

[0026] Figure 2 This is a schematic diagram of the cross-section of the ingate in this invention;

[0027] Figure 3 This is a schematic diagram of the cross-section of the slot gating system in this invention;

[0028] Figure 4 This is a schematic diagram of the cold iron layout in this invention;

[0029] Figure 5 This is a schematic diagram of the cast sample in this invention;

[0030] In the figure, 1-top sampling position; 2-middle sampling position; 3-bottom sampling position; 4-ingate width; 5-vertical sprue diameter; 6-cast body; 7-sprue; 8-iron chill; 9-aluminum chill; 10-attached casting sample; 11-horizontal sprue; 12-sample riser. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0032] This invention is mainly used to improve the casting quality of TiB2 particulate aluminum-based ceramic composite materials. It involves in-depth exploration and detailed analysis of the alloy's smelting process and casting process, resulting in suitable engineering application parameters for the alloy's smelting, as detailed below:

[0033] For alloy melt refining, CoverAL 1565 solvent was used as the slagging agent, and the alloy melt underwent two slagging refining processes. The first slagging refining temperature was 755–765℃, and the amount of CoverAL 1565 solvent added was 0.75–0.9% of the total alloy volume. The second slagging refining temperature was 730–740℃, and the amount of CoverAL 1565 solvent added was 0.1–0.2% of the total alloy volume. During the first and second slagging processes, the argon gas flow rate should not be too high, and the rotation speed of the stirring device should be appropriate. After the first and second slagging processes, slag removal was performed, followed by normal argon gas refining. The melt is refined using a rotary jet method at a temperature of 725–730℃ for 20–25 minutes. After refining, the melt is allowed to stand for 8–10 minutes before slag removal, followed by casting. The pressure casting parameters are as follows: liquid rise / filling speed: 70–90 mm / s; liquid rise pressure: PZL114A+10–15 kPa (PZL114A is the liquid rise pressure of ZL114A alloy); filling pressure: PZL114A+30–50 kPa (PZL114A is the filling pressure of ZL114A alloy); crystallization pressurization rate: 2.0 kPa / s; and casting temperature: 735–740℃.

[0034] Example:

[0035] Step 1: Preparation before pouring, preparation of the gating system, refer to... Figure 1 The sprue design of the casting was adjusted by widening the ingate of the sprue to improve the filling capacity of the alloy liquid. The engineering application parameters for the vertical sprue and ingate were determined: with a vertical sprue diameter of 5mm and a 60mm diameter, the sprue spacing was 85mm and the ingate width was 4mm; with a vertical sprue diameter of 5mm and a 75mm diameter, the ingate width was 49mm. (Refer to...) Figure 2 The attached casting specimen 10 was changed from the conventional top layout to a bottom layout, and a double-sided aluminum-clad chill and a riser were designed at the top of the specimen to improve the internal quality of the attached casting specimen. The attached casting specimen 10 is located between the two transverse runners 11 of the bottom plate, with a length of 170 mm. The specimen riser 12 has a height of 25 mm and a draft angle of 9°. The chills are double-sided aluminum-clad chills 9, and the chill thickness is 1.2 times the specimen thickness. The chill layout of the casting skin is completed using a combination of aluminum chills and iron chills. Aluminum chills are used for quenching in other parts of the casting skin, while iron chills are used for quenching in the area directly opposite the casting skin runners. The thicknesses of the two types of chills are completely different, as detailed below: (Refer to...) Figure 3The casting skin adopts a full-coverage chill process. The casting body 6 is connected to the gating system 7. The gating system 7 is made of iron chill 8, which is twice the thickness of the casting skin. The other skin parts are made of aluminum chill 9, which is 0.8 times the thickness of the casting skin, but the thickness cannot be less than 6mm.

[0036] Step 2: Refining the alloy melt. CoverAL1565 solvent was used as the slagging agent for the alloy melt, and the alloy melt was refined twice. The first slagging refining temperature was 765℃, and the amount of CoverAL1565 solvent added was 0.9% of the total alloy volume. The second slagging refining temperature was 736℃, and the amount of CoverAL1565 solvent added was 0.1% of the total alloy volume. After the first and second slagging, the slag was removed, and then the melt was refined by the normal argon rotary blowing method at a refining temperature of 728℃ for 22 minutes. After refining, the melt was allowed to stand for 10 minutes before removing the slag.

[0037] Step 3: After slag removal, casting is performed. The casting parameters are different from those of commonly used Al-Si alloys such as ZL101A and ZL114A, and are effectively adjusted according to the solidification characteristics of the alloy. The specific pressure casting parameters are: liquid rise / filling rate of 80 mm / s, liquid rise pressure of 50 kPa, filling pressure of 80 kPa, crystallization pressurization rate of 2.0 kPa / s, and casting temperature of 736℃.

[0038] Step 4: Sampling and analysis, refer to Figure 4 and Figure 5 Based on the alloy characteristics, powder samples were taken from three locations—top, middle, and bottom—in the sprue for alloy chemical composition analysis to address the issue of low Ti and B levels observed with conventional alloy ingot sampling methods. The alloy chemical composition sampling method is as follows: powder samples were taken from three locations—top, middle, and bottom—at the contact section between the sprue and the casting body, mixed, and then sent for testing. Specifically, sampling location 1 at the top of the sprue was 30 mm from the top plane, sampling location 3 at the bottom of the sprue was 70 mm from the bottom plane, and sampling location 2 in the middle was 18 mm from the centerline. All three sampling locations were 7 mm apart from the edge of the sprue.

[0039] The foregoing has provided a detailed description of the casting method for a TiB2 particle aluminum-based ceramic composite material provided by this invention. Specific examples have been used to illustrate the structure and working principle of this invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this invention.

Claims

1. A casting method for a TiB2 particle aluminum-based ceramic composite material, characterized in that: Includes the following steps: Step 1: Alloy melt refining. CoverAL1565 solvent is used as the slagging agent for the alloy melt, and the alloy melt is subjected to two slagging refining processes. The amount of solvent added is 0.1% to 0.9% of the total alloy volume. Step 2: Design the sprue, widen the ingate of the sprue. The ingate width should be 36-40mm for a sprue diameter of 60mm and 48-50mm for a sprue diameter of 75mm. Step 3: After the attached sample and casting skin layout are completed, the casting is poured. The attached sample adopts a bottom layout, and the casting skin adopts a chill layout, which is a combination of aluminum chills and iron chills. Aluminum chills are used for quenching in other parts of the casting skin, while iron chills are used for quenching in the area directly opposite the gating. Specifically, the attached sample layout is as follows: the position is between the two horizontal gatings of the bottom plate, the length is 160-180mm, the riser height is 20-30mm, the riser draft angle is 8-10°, and the chills are aluminum-clad on both sides, with a thickness of 1-1.5 times the sample thickness. The casting skin layout is as follows: iron chills are used directly opposite the gating, with a thickness of 1.5-2 times the casting skin thickness; aluminum chills are used in other skin areas, with a thickness of 0.5-0.8 times the casting skin thickness, but not less than 6mm. Step 4: Sampling and analysis. The alloy chemical composition is analyzed by taking samples at three locations: the top, middle, and bottom of the gating system. The three sampling locations are kept at least 5 mm away from the edge of the gating system.

2. The casting method for the TiB2 particle aluminum-based ceramic composite material according to claim 1, characterized in that: In step 1, the specific process of the two slag refining processes is as follows: the temperature of the first slag refining is 755-765℃, and the amount of CoverAL1565 solvent added is 0.75-0.9% of the total alloy volume; the temperature of the second slag refining is 730-740℃, and the amount of CoverAL1565 solvent added is 0.1-0.2% of the total alloy volume.

3. The casting method for the TiB2 particle aluminum-based ceramic composite material according to claim 2, characterized in that: After two slag-forming processes, an argon rotary jet method is used for refining at a temperature of 725–730℃ for 20–25 minutes. After refining, the mixture is allowed to stand for 8–10 minutes before slag removal and casting.

4. The casting method for the TiB2 particle aluminum-based ceramic composite material according to claim 1, characterized in that: In step 2, the designed gating gap spacing is 80-100mm.

5. The casting method for the TiB2 particle aluminum-based ceramic composite material according to claim 1, characterized in that: The pressure parameters for the casting process in step 3 are as follows: liquid lifting / filling speed is 70-90 mm / s, liquid lifting pressure is 45-90 kPa, filling pressure is 75-125 kPa, crystallization pressurization speed is 2.0 kPa / s, and casting temperature is 735-740℃.

6. The casting method for the TiB2 particle aluminum-based ceramic composite material according to claim 1, characterized in that: In step 4, the alloy chemical composition is sampled as follows: samples are taken from three locations—upper, middle, and lower—at the contact section between the gating system and the casting body, mixed, and then sent for testing.

7. The casting method for the TiB2 particle aluminum-based ceramic composite material according to claim 6, characterized in that: The three sampling locations are the top, middle, and bottom of the slot gating. The top sampling location is 20-60mm away from the top plane, the bottom sampling location is 50-80mm away from the bottom plane, and the middle sampling location is 20mm away from the center line.

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