Composite-strengthened heat-resistant and wear-resistant aluminum alloy and preparation method thereof

Abstract

The present disclosure relates to a composite-strengthened heat-resistant and wear-resistant aluminum alloy and a preparation method thereof, and belongs to the field of preparation of high-performance metal materials. In the composite-strengthened heat-resistant and wear-resistant aluminum alloy of the present disclosure, an AlSiCuMg alloy is adopted as a matrix, and microalloying elements for improving the heat resistance and a heat-resistant high-entropy alloy (HEA) for improving the wear resistance are added to allow composite strengthening. The preparation method mainly includes the following steps sequentially: smelting and alloying, blowing and refining, blow-compounding, die-casting molding, solution treatment, water quenching, and cryogenic and aging composite heat treatment.

Claims

1. A composite-strengthened heat-resistant and wear-resistant aluminum alloy, comprising an AlSiCuMg alloy matrix, microalloying elements Ti, Zr, Hf, and V added to the alloy matrix, and further comprising a high-entropy alloy powder Al.sub.1.5Ti.sub.0.5Zr.sub.0.5V.sub.0.5Hf.sub.0.5 blown into a melt of the aluminum alloy for composite strengthening; wherein the AlSiCuMg alloy matrix comprises the following elements in mass percentages: Si: 9.5% to 12.0%, Cu: 2.0% to 4.0%, Mg: 0.6% to 0.8%, and Al: the balance; the microalloying elements Ti, Zr, Hf, and V are added in mass percentages as follows: Ti: 0.05% to 0.25%, Zr: 0.05% to 0.25%, Hf: 0.01% to 0.05%, and V: 0.08% to 0.25%: and an amount of the high-entropy alloy powder added is 1 wt. % to 3 wt. % of an amount of the aluminum alloy matrix.

2. The composite-strengthened heat-resistant and wear-resistant aluminum alloy according to claim 1, wherein heat-resistant and wear-resistant phases existing in the alloy comprise composite phases of Si, Al.sub.3Zr, Al.sub.3Ti, Al.sub.3Hf, Al.sub.2Cu, Mg.sub.2Cu, Mg.sub.2Si, and Al.sub.1.5Ti.sub.0.5Zr.sub.0.5V.sub.0.5Hf.sub.0.5.

3. A preparation method of the composite-strengthened heat-resistant and wear-resistant aluminum alloy according to claim 1, comprising the following steps: step 1: smelting and alloying: melting an industrial pure aluminum ingot in a heating furnace, and adding an aluminum-silicon alloy, an aluminum-magnesium alloy, and an aluminum-copper alloy successively, wherein mass percentages of components are controlled as follows: Si 9.5% to 12.0%, Cu: 2.0% to 4.0%, and Mg: 0.6% to 0.8%; and performing microalloying with alloying elements Ti, Zr, Hf, and V, wherein mass percentages of the alloying elements Ti, Zr, Hf, and V are controlled as follows: Ti: 0.05% to 0.25%, Zr: 0.05% to 0.25%, Hf: 0.01% to 0.05%, and V: 0.08% to 0.25%; step 2: blowing and refining: blowing argon to allow refining at 700 C. to 740 C.; step 3: blow-compounding: with argon as a carrier gas, blowing a high-entropy alloy powder Al.sub.1.5Ti.sub.0.5Zr.sub.0.5V.sub.0.5Hf.sub.0.5 into a melt of the aluminum alloy, blowing for thorough stirring while controlling the melt at 700 C., and allowing the melt to stand for 10 min to 15 min to wait for molding; and step 4: cast molding: injecting the melt into a casting machine to allow cast molding.

4. The preparation method of the composite-strengthened heat-resistant and wear-resistant aluminum alloy according to claim 3, wherein in the step 4, the cast molding is die-casting molding, the melt is injected into a die-casting machine for die-casting molding at 680 C. to 700 C., and the die-casting molding is performed under a pressure of 80 MPa to 90 MPa.

5. The preparation method of the composite-strengthened heat-resistant and wear-resistant aluminum alloy according to claim 4, further comprising: step 5: a solution-aging treatment: heating an obtained cast alloy to a temperature of 530 C. to 540 C., keeping the cast alloy at the temperature for 6 h to 12 h, and furnace-cooling.

6. The preparation method of the composite-strengthened heat-resistant and wear-resistant aluminum alloy according to claim 4, further comprising: step 5: a solution-water quenching heat treatment: cooling a cast alloy obtained in the step 4 to room temperature, allowing the cast alloy to stand, heating the cast alloy to 535 C. to 545 C., and performing a solution treatment for 60 min to 80 min; and after the solution treatment is completed, performing water quenching with water temperature at 25 C. to 40 C. for 30 s to 60 s, and after the water quenching is completed, cooling the cast alloy to room temperature.

7. The preparation method of the composite-strengthened heat-resistant and wear-resistant aluminum alloy according to claim 6, wherein the step 5 further comprises a cryogenic treatment, and the cryogenic treatment is performed with liquid nitrogen at 196 C. for 24 h to 36 h after the water quenching and a surface-drying.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a scanning electron microscopy (SEM) image of a metallographic structure of the composite-strengthened heat-resistant and wear-resistant aluminum alloy obtained in Example 2 of the present disclosure; and

(2) FIG. 2 is an SEM image of a metallographic structure of the composite-strengthened heat-resistant and wear-resistant aluminum alloy obtained in Example 3 of the present disclosure.

DESCRIPTION OF EMBODIMENTS

(3) In order to allow those skilled in the art to well understand the technical solutions of the present disclosure, the present disclosure is further described in detail below in conjunction with the accompanying drawings. It should be understood that these examples are provided merely to illustrate the present disclosure, but not to limit the scope of the present disclosure in any way. In the following examples, various processes and methods that are not described in detail are conventional methods well known in the art.

(4) A microhardness test of an aluminum alloy is performed on a digital microhardness tester; a wear test of an aluminum alloy is performed on an MMU-5GA microcomputer-controlled high-temperature friction wear testing machine; a specimen is a pin-shaped specimen with a size of 4.8 mm12.7 mm, and a grinding material is GCr15 steel processed into a D54 mm8 mm disc specimen; dry sliding friction wear is adopted, an experimental temperature is 25 C., a load is 150N, a rotational speed is 50 r/min, and a wear time is 20 min; the wear resistance is expressed by a wear weight loss; and the high temperature resistance is measured by tensile strength and hardness indexes at 300 C.

Example 1

(5) In this example, an AlSiCuMg alloy matrix included the following target elements in mass percentages: Si: 10.5%, Cu: 3.0%, Mg: 0.7%, and Al: the balance; microalloying elements Ti, Zr, Hf, and V were added according to the following amounts: Ti: 0.15%, Zr: 0.15%, Hf: 0.02%, and V: 0.15%; and a mass percentage of an Al.sub.1.5Ti.sub.0.5Zr.sub.0.5V.sub.0.5Hf.sub.0.5 HEA was 2% of a mass percentage of the AlSiCuMg alloy matrix. Unless otherwise specified, the contents of all components in the present disclosure were expressed in mass percentages.

(6) In this example, atmospheric pressure casting was adopted, and a preparation process was as follows.

(7) Step 1: Smelting and Alloying

(8) 100 kg of an industrial pure aluminum ingot was melted in a medium-frequency induction heating furnace and heated to 700 C., and an aluminum-silicon alloy, an aluminum-magnesium alloy, and an aluminum-copper alloy were added successively to prepare an AlSiCuMg alloy matrix, where contents of Si, Mg, and Cu were controlled as follows: Si: 10.5%, Cu: 3.0%, and Mg: 0.7%; and microalloying was performed with Ti, Zr, Hf, and V, where contents of the alloying elements Ti, Zr, Hf, and V were controlled as follows: Ti: 0.15%, Zr: 0.15%, Hf: 0.02%, and V: 0.15%.

(9) Step 2: Blowing and Refining

(10) A specific process of step 2 was as follows: Argon was blown to allow refining at 720 C. for 15 min.

(11) Step 3: Blow-Compounding

(12) After the blowing and refining was completed, with argon as a carrier gas, an HEA Al.sub.1.5Ti.sub.0.5Zr.sub.0.5V.sub.0.5Hf.sub.0.5 powder for composite strengthening was blown into an aluminum alloy melt, blowing was performed for thorough stirring while controlling the aluminum alloy melt at 700 C., and the resulting melt was allowed to stand for 10 min.

(13) Step 4: Atmospheric Pressure Casting Was Performed.

Example 2

(14) The same composition and the same steps 1, 2, and 3 as those in Example 1 were adopted in this example, but die-casting molding was adopted in step 4. Specifically, a melt was injected into a die-casting machine when at 690 C., and the die-casting molding was performed with a casting pressure of 85 MPa and a holding time of 15 s.

(15) The preparation method further included: Step 5, Solution-aging heat treatment

(16) The resulting cast alloy was heated to 530 C. to 540 C., kept at this temperature for 6 h to 12 h, and then furnace-cooled.

(17) An SEM image of a metallographic structure of the composite-strengthened heat-resistant and wear-resistant aluminum alloy obtained in Example 2 was shown in FIG. 1.

Example 3

(18) The same composition and the same steps 1, 2, and 3 as those in Example 1 were adopted in this example, but die-casting molding was adopted in step 4. Specifically, a melt was injected into a die-casting machine when at 690 C., and the die-casting molding was performed with a casting pressure of 85 MPa and a holding time of 15 s.

(19) The preparation method further included: Step 5, Solution treatment-water quenching-cryogenic composite heat treatment.

(20) A cast alloy obtained in step 4 was cooled to room temperature, then allowed to stand for more than 12 h, and subjected to a solution treatment in a heating furnace at 540 C. for 70 min; after the solution treatment was completed, the cast alloy was quenched with water at 30 C. for 35 s; and after the quenching was completed, the cast alloy was cooled to room temperature, the surface water was wiped off, and the cast alloy was subjected to a cryogenic treatment directly in liquid nitrogen at 196 C. for 30 h, then taken out, and naturally warmed to room temperature.

(21) An SEM image of a metallographic structure of the composite-strengthened heat-resistant and wear-resistant aluminum alloy obtained in Example 3 was shown in FIG. 2. Heat-resistant and wear-resistant phases in the prepared aluminum alloy included a Si phase and Al.sub.3Hf, Al.sub.3Zr, Al.sub.3Ti, Al.sub.2Cu, Mg.sub.2Cu, Mg.sub.2Si, and Al.sub.1.5Ti.sub.0.5Zr.sub.0.5V.sub.0.5Hf.sub.0.5 composite phases. Compared with the material prepared in Example 2, a number of composite phases in the material prepared in this example was significantly increased.

(22) The aluminum alloy prepared in Example 1 was subjected to a friction wear test, a microhardness test, and tensile strength and hardness tests reflecting heat resistance at 350 C. and experimental results were shown in Table 1. In contrast to the present disclosure, the current wear-resistant and heat-resistant aluminum alloys of AlSi die-casting aluminum alloy A360, AlSiCu die-casting aluminum alloy A380, AlCuMg aluminum alloy 2024, and AlZnMgCu superhard aluminum alloy 7075 on the market were adopted as Comparative Examples 1, 2, 3, and 4,respectively, these aluminum alloys were compared with the aluminum alloys prepared in Examples 1, 2, and 3, and results were shown in Table 1.

(23) TABLE-US-00001 TABLE 1 Comparison of performance data of the examples and comparative examples Tensile Wear Hardness strength Hardness Strength- weight at room at a high at a high failing loss, temperature, temperature, temperature, temperature/ mg Hv MPa Hv C. Example 1 (atmospheric 120 155 320 140 380 pressure casting) Example 2 (die casting + 105 170 330 150 390 solution-aging treatment) Example 3 (die casting + 95 180 370 175 395 solution treatment-water quenching-cryogenic composite heat treatment) Comparative Example 1 220 85 97 70 290 (A360) Comparative Example 2 200 95 100 75 290 (A380) Comparative Example 3 140 140 290 120 300 (2024) Comparative Example 4 135 150 310 125 340 (7075)

(24) It can be seen from the comparison of performance test results of examples and Comparative Examples 1 to 4 in Table 1 that, compared with the current major wear-resistant and heat-resistant aluminum alloys on the market, the heat-resistant and wear-resistant aluminum alloy obtained in the present disclosure is significantly improved in terms of a wear weight loss index and a room-temperature hardness index reflecting wear resistance, where the wear resistance at room temperature is increased by 20% or more, the hardness at room temperature is increased by 17% or more, the tensile strength at a high temperature is increased by 19.4% or more, the hardness at a high temperature is increased by 40%, and the strength-failing temperature is increased by 55 C. to 105 C.

(25) It can be seen from test results of the composite-strengthened heat-resistant and wear-resistant aluminum alloy materials prepared in Examples 1 and 2 of the present disclosure and the current heat-resistant wear-resistant alloys adopted in Comparative Examples 1 to 4 that the composite-strengthened heat-resistant and wear-resistant aluminum alloy of the present disclosure has obvious performance advantages in terms of wear resistance, room temperature hardness, high temperature tensile strength, high temperature hardness, and heat resistance temperature, indicating that the composite-strengthened heat-resistant and wear-resistant aluminum alloy of the present disclosure has significant outstanding progress characteristics compared with the existing materials.

(26) It can be seen from the comparison of Example 3 with Examples 1 and 2 that the die-casting molding and solution treatment-water quenching-cryogenic composite heat treatment in the preparation method of the composite-strengthened heat-resistant and wear-resistant aluminum alloy of the present disclosure have beneficial effects and progresses.

(27) In a word, it can be seen from the comparison between examples and comparative examples that the composite-strengthened heat-resistant and wear-resistant aluminum alloy and the preparation method thereof in the present disclosure have significant progresses and obvious beneficial effects compared with the prior art.