1. A heat treatment process for spray forming a high-silicon wear-resistant aluminum alloy, which has an aluminum alloy composition containing 24 to 26 mass% of Si, 3.5 to 4.5 mass% of Cu, 0.8 to 1.2 mass% of Mg, and inevitable impurities, characterized by comprising the steps of:

firstly, carrying out spray forming on the raw materials of the components to prepare an ingot blank;

secondly, hot extruding the ingot blank into an extruded alloy;

thirdly, homogenizing and annealing the extruded alloy at 480 +/-2 ℃ for 24 +/-0.1 h;

fourthly, air cooling is carried out after discharging;

carrying out solution treatment at the temperature of 520 +/-2 ℃ for 2 +/-0.1 h, and then carrying out water quenching to room temperature;

sixthly, carrying out isothermal aging heat treatment on the solid solution alloy at the temperature of 175-185 ℃ for 0-15 h.

2. The heat treatment process of spray forming high silicon wear resistant aluminum alloy according to claim 1, wherein the isothermal aging heat treatment time in step (c) is 6-7 h.

3. The heat treatment process for spray forming of the high-silicon wear-resistant aluminum alloy as claimed in claim 1, wherein in the step (i), C is added in an amount of 0.1-0.4% by mass before melting₂Cl₆And (4) refining.

4. The heat treatment process for spray forming of the high-silicon wear-resistant aluminum alloy as claimed in claim 1, wherein in the step (i), the refining time is 3-10min, the refined high-silicon wear-resistant aluminum alloy is left for 10-30min and then filtered, and the high-purity inert gas is atomized after the filtering is completed.

Background

The main traditional methods for preparing the aluminum-silicon alloy include a powder metallurgy method and a casting method. The main disadvantages of powder metallurgy are high production cost, complex process, and need of subsequent processing for obtaining higher density, and generally used for producing products with less batch; the microstructure of the aluminum-silicon alloy prepared by the casting method mainly comprises a coarse, isolated and multi-faceted primary crystalline silicon phase, which is very unfavorable for the mechanical property and the processing property of the material.

The spray forming technology is not limited by the upper limit of the alloy content, the free design of the alloy formula can be realized, the technology overcomes the defects of the two traditional preparation methods, and the technology becomes the mainstream technology for producing high-silicon aluminum alloy products.

The high-silicon aluminum alloy prepared by adopting the spray forming technology has the characteristics of fine structure, uniform phase distribution of silicon crystal and intermetallic compounds, capability of performing extrusion processing, heat treatment strengthening, excellent mechanical processing performance and the like, and the excellent tribological performance potential of the high-silicon aluminum alloy material is developed.

At present, the high-silicon aluminum alloy is an environment-friendly light wear-resistant material with wide application prospect, and has small thermal expansion coefficient, high volume stability, excellent wear resistance, corrosion resistance and certain high-temperature strength, so that the high-silicon aluminum alloy is widely applied to the fields of automobiles (wear-resistant parts such as brake drums, engine rotors, swash plates and the like), aviation, aerospace and the like, is applied to the field of electronic packaging, and is particularly applied to the field of electronic packaging of military electronic devices with high integration and light weight.

In recent years, research and preparation of high-silicon aluminum alloy are important breakthrough, engineering application is more and more, but the problem of low strength is also found in the engineering application process, and the high-silicon aluminum alloy becomes a potential safety hazard in the long-term use process. Therefore, the need of improving the mechanical properties of high-silicon wear-resistant aluminum alloy through a heat treatment process to have excellent comprehensive properties still remains in the field.

Disclosure of Invention

The invention aims to solve the defects of the prior art and provides a heat treatment process for spray forming of high-silicon wear-resistant aluminum alloy.

The processed object is a high-silicon aluminum alloy, which is prepared by adding 24-26% (mass percent) of Si, 3.5-4.5% (mass percent) of Cu, 0.8-1.2% (mass percent) of Mg and some inevitable impurities on the basis of pure aluminum.

The preparation method of the alloy comprises the steps of melting the components of the aluminum-silicon-copper-magnesium alloy in a smelting furnace, and adding 0.1-0.4% of C in the total mass into the melt₂Cl₆And refining, stirring by an electromagnetic stirring device for 3-10min, standing for 10-30min after refining, filtering, atomizing the filtered alloy melt by high-purity inert gas, simultaneously rotating a receiving disc under the driving of a motor, pulling down at the speed of 20-35 mm/s, preparing an alloy ingot blank, cooling the alloy ingot blank, and taking out to obtain the sprayed aluminum-silicon-copper-magnesium material.

And (3) carrying out hot extrusion on the sprayed aluminum-silicon-copper-magnesium ingot blank to further improve the compactness of the ingot blank, thereby obtaining an extruded material. Then carrying out homogenizing annealing, solid solution and aging heat treatment on the F-state extruded material, and specifically comprising the following steps:

(1) firstly, carrying out homogenizing annealing at 480 +/-2 ℃, keeping the temperature for 24 +/-0.1 h, and then discharging from the furnace for air cooling;

(2) secondly, carrying out solution treatment at 520 +/-2 ℃ for 2 +/-0.1 h, and carrying out water quenching to room temperature;

(3) and finally, carrying out isothermal aging heat treatment on the solid solution alloy at 175-185 ℃ for 0-15h at different time, wherein the optimal isothermal aging temperature is 180 +/-1 ℃, and the optimal isothermal aging time is 6-7 h.

Has the advantages that:

the high-silicon aluminum alloy prepared by adopting the spray forming technology has the characteristics of fine structure, uniform phase distribution of silicon crystal and intermetallic compounds, excellent hot extrusion processing, heat treatment strengthening, mechanical processing performance and the like, so that the excellent tribological performance potential of the high-silicon aluminum alloy material is developed.

The high-silicon wear-resistant aluminum alloy is subjected to heat treatment at the optimal isothermal aging temperature of 180 +/-1 ℃ and the optimal isothermal aging time of 6-7h, the tensile strength can reach 481MPa, the corresponding hardness is about 200MPa, and the material not only has ultrahigh wear resistance, but also has good mechanical properties.

Drawings

FIG. 1 shows the comparison values of tensile strength of high-silicon wear-resistant aluminum alloy after different aging processes.

Detailed Description

For the purpose of enhancing the understanding of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, which are only used for explaining the present invention and are not to be construed as limiting the scope of the present invention.

The first embodiment is as follows: the aluminum-silicon-copper-magnesium alloy ingot blank is prepared by adopting a spray forming process, and the used raw materials comprise high-purity aluminum, industrial silicon, cathode copper and primary magnesium ingot. Taking Si according to weight percentage: 24-26%, Cu: 3.5-4.5%, Mg: 0.8 to 1.2 percent of Fe, less than or equal to 0.4 percent of Fe and the balance of Al, the alloy components are melted in a smelting furnace, and C with the total mass of 0.1 to 0.4 percent is added into the melt₂Cl₆Refining, stirring by an electromagnetic stirring device for 3-10min, standing for 10-30min after refining, filtering, atomizing the filtered alloy melt by high-purity inert gas, simultaneously driving a receiving disc to rotate and pull down at the speed of 20-35 mm/s under the drive of a motor to prepare an alloy ingot blank, cooling the alloy ingot blank, taking out the cooled alloy ingot blank to obtain a spray-state ingot blank, carrying out hot extrusion on the spray-state ingot blank, and further improving the compactness of the spray-state ingot blank to obtain an extruded material.

Comparative example one: the extruded material in the first embodiment is firstly subjected to homogenizing annealing treatment at 480 +/-2 ℃, heat preservation is carried out for 24 +/-0.1 h, then the extruded material is discharged from a furnace and air cooled, then solution treatment is carried out at 520 +/-2 ℃, the temperature of a sample is raised along with the furnace, the temperature is preserved for 2 +/-0.1 h after the temperature is raised, the extruded material is discharged from the furnace and water quenched to the room temperature, and finally isothermal aging heat treatment is carried out on the solid solution alloy for 0-15h at 175 +/-1 ℃. As can be seen from FIG. 1, under the heat treatment process conditions specified in comparative example I, the tensile strength of the material reached a peak of 464MPa at 6h of aging, which is 17MPa lower than the peak strength in example II.

Example two: the extruded material in the embodiment 1 is firstly subjected to homogenizing annealing treatment at 480 +/-2 ℃, is kept warm for 24 +/-0.1 h, is taken out of a furnace for air cooling, is then subjected to solution treatment at 520 +/-2 ℃, is heated along with the furnace, is kept warm for 2 +/-0.1 h after reaching the temperature, is taken out of the furnace for water quenching to the room temperature, and is finally subjected to isothermal aging heat treatment at 180 +/-1 ℃ for 0-15h at different times. As can be seen from FIG. 1, under the heat treatment conditions specified in example two, the material had a peak tensile strength of 481MPa at 6h of aging, which is 1.25 times that of the solid solution state, and at this time, the corresponding hardness was 200HV, and the tensile strength gradually decreased with the increase of the aging time, and was only 455MPa at 15h of aging time.

Comparative example two: the extruded material in the first embodiment is firstly subjected to homogenizing annealing treatment at 480 +/-2 ℃, heat preservation is carried out for 24 +/-0.1 h, then the extruded material is discharged from a furnace and air cooled, then solution treatment is carried out at 520 +/-2 ℃, the temperature of a sample is raised along with the furnace, the temperature is preserved for 2 +/-0.1 h after the temperature is raised, the extruded material is discharged from the furnace and water quenched to the room temperature, and finally isothermal aging heat treatment is carried out on the solid solution alloy for 0-15h at 185 +/-1 ℃. As can be seen from FIG. 1, under the heat treatment process conditions specified in comparative example II, the material reached a peak tensile strength of 467MPa at 6h of aging, which was 14MPa lower than the peak strength in example II.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.