GRAPHENE- AND IN-SITU NANOPARTICLE-REINFORCED ALUMINUM-BASED COMPOSITE MATERIAL AND PREPARATION METHOD

Abstract

A graphene and in-situ nano-ZrB.sub.2 particle-co-reinforced aluminum matrix composite (AMC) and a preparation method thereof are provided. The preparation method includes: heating an aluminum alloy for melting, adding potassium fluoroborate and potassium fluorozirconate to produce ZrB.sub.2 particles in-situ, additionally adding a mixture of pre-prepared copper-coated graphene and an aluminum powder, and stirring with an electromagnetic field for uniform dispersion; and ultrasonically treating the resulting melt to improve the dispersion of the in-situ nano-ZrB.sub.2 particles and the graphene, casting for molding to obtain a casting, and subjecting the casting to homogenization and rolling for deformation to obtain the graphene and in-situ nano-ZrB.sub.2 particle-co-reinforced AMC. The in-situ generation of the reinforcement nano-ZrB.sub.2 particles in an aluminum alloy melt increases the number of interfaces in the composite and also increases the dislocation density.

Claims

1. A preparation method of a graphene and in-situ nanoparticle-co-reinforced aluminum matrix composite, comprising: heating an aluminum alloy for melting, adding potassium fluoroborate and potassium fluorozirconate to produce in-situ nano-ZrB.sub.2 particles, additionally adding a mixture of pre-prepared copper-coated graphene nanosheets and an aluminum powder, followed by stirring with an electromagnetic field for an uniform dispersion to obtain a resulting melt; and ultrasonically treating the resulting melt to improve a dispersion of the in-situ nano-ZrB.sub.2 particles and the pre-prepared copper-coated graphene nanosheets, followed by casting for molding to obtain a casting, and subjecting the casting to homogenization and rolling for a deformation to obtain a graphene and in-situ nano-ZrB.sub.2 particle-co-reinforced aluminum matrix composite, wherein the preparation method specifically comprises the following steps: (1) a pretreatment of raw materials for producing the nano-ZrB.sub.2 particles: taking and thoroughly mixing the potassium fluoroborate and the potassium fluorozirconate according to a molar ratio of (2-2.1):1 to obtain a first resulting mixture, and preheating the first resulting mixture to 300° C. to 500° C. for later use; (2) a preparation of the pre-prepared copper-coated graphene; (3) a mixing of copper-coated graphene and the aluminum powder: mixing and ball-milling the copper-coated graphene and the aluminum powder for 1 h to 3 h in a ball mill under an Ar atmosphere according to a mass ratio of 1:(1-2) to obtain a mixture; (4) a preparation of an as-cast aluminum matrix composite: heating an aluminum alloy melt to 850° C. to 900° C., adding pretreated potassium fluoroborate and potassium fluorozirconate to allow a reaction for 25 min to 30 min to produce the nano-ZrB.sub.2 particles, during the reaction, an electromagnetic stirring is conducted for a particle dispersion; cooling to a predetermined temperature, and adding the mixture of the copper-coated graphene and the aluminum powder to the aluminum alloy melt under a mechanical stirring to obtain a second resulting mixture; and subjecting the second resulting mixture to an ultrasonic treatment, and casting to obtain the as-cast aluminum matrix composite; (5) a homogenization: keeping the as-cast aluminum matrix composite at 560° C. for 20 h to 25 h; and (6) a rolling: rolling a homogenized composite at 450° C. to 480° C. for the deformation to finally obtain the graphene and in-situ nano-ZrB.sub.2 particle-co-reinforced aluminum matrix composite; wherein in the graphene and in-situ nano-ZrB.sub.2 particle-co-reinforced aluminum matrix composite, a content of the copper-coated graphene is 0.01 wt. % to 1 wt. %, a content of the nano-ZrB.sub.2 particles is 0.01 wt. % to 3 wt. %, and the balance is an AA6111 aluminum alloy.

2. (canceled)

3. The preparation method of the graphene and in-situ nanoparticle-co-reinforced aluminum matrix composite according to claim 1, wherein the copper-coated graphene is prepared through a chemical plating process; and the chemical plating process comprises the following steps: a surface treatment of graphene: subjecting the graphene to an ultrasonic dispersion in deionized water for 40 min to 60 min to obtain a 0.5 g/L to 3 g/L graphene dispersion, adding a reagent to the 0.5 g/L to 3 g/L graphene dispersion to prepare a sensitizing solution, stirring the sensitizing solution for 40 min to 60 min to allow a sensitization treatment, filtering sensitized graphene out, and washing the sensitized graphene; adding the sensitized graphene to a 10 g/L AgNO.sub.3 solution, slowly injecting an aqueous ammonia until a solid is completely dissolved, stirring at room temperature for 40 min to 60 min to allow an activation, filtering sensitized and activated graphene out, and washing the sensitized and activated graphene; adding the sensitized and activated graphene to a 15 g/L to 20 g/L sodium hypophosphite solution to obtain a third resulting mixture, subjecting the third resulting mixture to an ultrasonic treatment for 3 min to 5 min, and allowing the third resulting mixture to stand at room temperature for 1 min to 2 min to remove a residual activation solution on a surface of the graphene; and filtering the graphene out, rinsing the graphene with distilled water until neutral, and drying the graphene at 50° C. to 60° C. for later use; and subjecting the graphene obtained after the surface treatment to the ultrasonic dispersion in deionized water for 3 min to 5 min to prepare a chemical plating solution; heating the chemical plating solution to 60° C. to 65° C., adding a formaldehyde solution to the chemical plating solution, and adding a NaOH solution dropwise to the chemical plating solution at a rate of 2 to 3 mL/3 min to maintain a pH of the chemical plating solution at 10 to 12, wherein an entire reduction process from a beginning of a dropwise addition of the NaOH solution to an end of the dropwise addition of the NaOH solution is controlled within 40 min to 50 min; filtering a product out, washing the product with pure water until neutral, and subjecting the product to a passivation with a passivation solution for 10 min to 15 min; and washing a passivated product with absolute ethanol until neutral, and drying the passivated product to obtain the copper-coated graphene.

4. The preparation method of the graphene and in-situ nanoparticle-co-reinforced aluminum matrix composite according to claim 3, wherein the graphene is a graphene nanosheet with a thickness of 3 nm to 5 nm and a diameter of 5 μm to 20 μm.

5. The preparation method of the graphene and in-situ nanoparticle-co-reinforced aluminum matrix composite according to claim 3, wherein the sensitizing solution comprises: SnCl.sub.2.Math.2H.sub.2O: 20 g/L to 30 g/L, and HCl: 0.5 mol/L to 0.6 mol/L; a volume ratio of the AgNO.sub.3 solution to the aqueous ammonia is 1,000:(12-15), and the aqueous ammonia has a concentration of 25 wt. %; and the chemical plating solution comprises: CuSO.sub.4.Math.5H.sub.2O: 15 g/L to 30 g/L, C.sub.4O.sub.6H.sub.4KNa: 20 g/L to 40 g/L, and ethylenediaminetetraacetic acid disodium (EDTA-2Na): 25 g/L to 50 g/L.

6. The preparation method of the graphene and in-situ nanoparticle-co-reinforced aluminum matrix composite according to claim 3, wherein the formaldehyde solution has a concentration of 37 wt. % and is added to the chemical plating solution first at an amount of 1.5% to 2% of a volume fraction of the chemical plating solution to allow a reduction for 2 min to 3 min and then at an amount of 3% to 4% of the volume fraction of the chemical plating solution; the NaOH solution used for a pH adjustment has a concentration of 37 wt. %; and the passivation solution is a solution of 0.5 wt. % to 1 wt. % benzotriazole in absolute ethanol.

7. The preparation method of the graphene and in-situ nanoparticle-co-reinforced aluminum matrix composite according to claim 1, wherein in the step (3), the aluminum powder has a particle size of 10 μm to 20 μm, and the mixture of the copper-coated graphene and the aluminum powder is ball-milled at a rotational speed of 200 rpm to 300 rpm.

8. The preparation method of the graphene and in-situ nanoparticle-co-reinforced aluminum matrix composite according to claim 1, wherein in the step (4), the cooling is conducted to 670° C. to 720° C.; the electromagnetic stirring is conducted at a frequency of 5 Hz to 20 Hz; the mechanical stirring is conducted at a rotational speed of 1,000 rpm to 1,200 rpm for 5 min to 10 min; and the ultrasonic treatment before the casting is conducted at an ultrasonic power of 1 kW to 2 kW for 30 s to 60 s.

9. The preparation method of the graphene and in-situ nanoparticle-co-reinforced aluminum matrix composite according to claim 1, wherein in the step (6), the rolling is conducted at a deformation amount of 50% to 95%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a schematic diagram of an experimental process of the present disclosure.

[0034] FIG. 2 shows scanning patterns of a microstructure in a rolling state, where (a) shows a surface parallel to a stress surface in a rolling direction (RD-TD surface) and (b) shows a surface parallel to a side surface in the rolling direction (RD-ND surface).

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] Example 1: A preparation method of an AMC co-reinforced with 0.01 wt. % graphene and 3 wt. % in-situ nano-ZrB.sub.2 particles was provided in this example, which was as follows:

[0036] (1) Pretreatment of raw materials for producing the 3 wt. % ZrB.sub.2 particles: 97.8 g of potassium fluoroborate and 91.2 g of potassium fluorozirconate were taken and thoroughly mixed, and then preheated to 300° C. for later use.

[0037] (2) Preparation of copper-coated graphene through a chemical plating process: surface treatment of graphene: 0.1 g of graphene was subjected to ultrasonic dispersion in 100 mL of deionized water for 50 min to obtain a 1 g/L graphene dispersion, a reagent was added to the graphene dispersion to prepare a sensitizing solution (3 g of SnCl.sub.2.Math.2H.sub.2O and 5 mL of 37 wt. % HCl), and the sensitizing solution was stirred at 25° C. for 50 min to allow a sensitization treatment; sensitized graphene was filtered out, washed, and added to 100 mL of a 10 g/L AgNO.sub.3 solution, 1.2 mL of aqueous ammonia was slowly injected until the solid was completely dissolved, and the resulting mixture was stirred at room temperature for 50 min to allow activation; sensitized and activated graphene was filtered out, washed, and added to a 20 g/L sodium hypophosphite solution, and the resulting mixture was subjected to an ultrasonic treatment for 3 min, and allowed to stand at room temperature for 1 min to remove the residual activation solution on a surface of the graphene; and the graphene was filtered out, rinsed with distilled water until neutral, and dried at 60° C. for later use; and

[0038] the graphene obtained after the surface treatment was subjected to ultrasonic dispersion in 100 mL of deionized water for 3 min, and a chemical reagent was added to prepare a chemical plating solution (1.5 g of CuSO.sub.4.Math.5H.sub.2O, 2 g of C.sub.4O.sub.6H.sub.4KNa, and 2.5 g of EDTA-2Na); the chemical plating solution was heated to 60° C., 1.5 mL of a formaldehyde solution was added dropwise to the chemical plating solution to allow reduction for 3 min, and then 3 mL of the formaldehyde solution was added, during which a 37 wt. % NaOH solution was added dropwise to the chemical plating solution at a rate of 2 mL/3 min to maintain a pH of the chemical plating solution at 11.5 to 12, where the entire reduction process from the beginning of the dropwise addition of the NaOH solution to the end of the dropwise addition of the NaOH solution was controlled within 40 min; a product was filtered out, washed with pure water until neutral, and subjected to passivation with a passivation solution for 15 min; and a passivated product was washed with absolute ethanol until neutral, and then dried to obtain a copper-coated graphene nanosheet.

[0039] (3) Mixing of the copper-coated graphene and an aluminum powder: 0.8 g of the copper-coated graphene and 1.6 g of the aluminum powder with a particle size of 20 μm were mixed and ball-milled for 1 h in a ball mill under an Ar atmosphere at a rotational speed of 200 rpm to obtain a mixture.

[0040] (4) Preparation of an as-cast AMC: 970 g of an AA6111 aluminum alloy melt was heated to 850° C., the pretreated potassium fluoroborate and potassium fluorozirconate were added to allow a reaction for 25 min to produce ZrB.sub.2 particles, during which EMS was conducted at 10 Hz for particle dispersion; the resulting reaction system was cooled to 700° C., and the mixture of the copper-coated graphene and the aluminum powder was added to the aluminum alloy melt under mechanical stirring at 1,000 rpm for 5 min; and the resulting mixture was heated to 720° C., then subjected to an ultrasonic treatment at 1.5 kW for 50 s, and casted to obtain the as-cast AMC.

[0041] (5) Homogenization: The as-cast AMC was kept at 560° C. for 20 h.

[0042] (6) Rolling: A homogenized composite was rolled at 450° C. with a deformation amount of 84% to finally obtain the graphene and in-situ nano-ZrB.sub.2 particle-co-reinforced AMC.

[0043] The AMC co-reinforced with 0.01 wt. % graphene and 3 wt. % in-situ nano-ZrB.sub.2 particles prepared in this example had a strength of 372 MPa and an elongation of 25%.

[0044] Example 2: A preparation method of an AMC co-reinforced with 0.1 wt. % graphene and 0.1 wt. % in-situ nano-ZrB.sub.2 particles was provided in this example, which was as follows:

[0045] (1) Pretreatment of raw materials for producing the 0.1 wt. % ZrB.sub.2 particles: 3.3 g of potassium fluoroborate and 3.0 g of potassium fluorozirconate were taken and thoroughly mixed, and then preheated to 300° C. for later use.

[0046] (2) Preparation of copper-coated graphene through a chemical plating process: surface treatment of graphene: 1 g of graphene was subjected to ultrasonic dispersion in 1 L of deionized water for 50 min to obtain a 1 g/L graphene dispersion, a reagent was added to the graphene dispersion to prepare a sensitizing solution (30 g of SnCl.sub.2.Math.2H.sub.2O and 50 mL of 37 wt. % HCl), and the sensitizing solution was stirred at 25° C. for 50 min to allow a sensitization treatment; sensitized graphene was filtered out, washed, and added to 1 L of a 10 g/L AgNO.sub.3 solution, 12 mL of aqueous ammonia was slowly injected until the solid was completely dissolved, and the resulting mixture was stirred at room temperature for 50 min to allow activation; sensitized and activated graphene was filtered out, washed, and added to a 20 g/L sodium hypophosphite solution, and the resulting mixture was subjected to an ultrasonic treatment for 3 min, and allowed to stand at room temperature for 1 min to remove the residual activation solution on a surface of the graphene; and the graphene was filtered out, rinsed with distilled water until neutral, and dried at 60° C. for later use; and

[0047] the graphene obtained after the surface treatment was subjected to ultrasonic dispersion in 1 L of deionized water for 3 min, and a chemical reagent was added to prepare a chemical plating solution (15 g of CuSO.sub.4.Math.5H.sub.2O, 20 g of C.sub.4O.sub.6H.sub.4KNa, and 25 g of EDTA-2Na); the chemical plating solution was heated to 60° C., 15 mL of a formaldehyde solution was added dropwise to the chemical plating solution to allow reduction for 3 min, and then 30 mL of the formaldehyde solution was added, during which a 37 wt. % NaOH solution was added dropwise to the chemical plating solution at a rate of 2 mL/3 min to maintain a pH of the chemical plating solution at 11.5 to 12, where the entire reduction process from the beginning of the dropwise addition of the NaOH solution to the end of the dropwise addition of the NaOH solution was controlled within 40 min; a product was filtered out, washed with pure water until neutral, and subjected to passivation with a passivation solution for 15 min; and a passivated product was washed with absolute ethanol until neutral, and then dried to obtain a copper-coated graphene nanosheet.

[0048] (3) Mixing of the copper-coated graphene and an aluminum powder: 8 g of the copper-coated graphene and 16 g of the aluminum powder with a particle size of 20 μm were mixed and ball-milled for 1 h in a ball mill under an Ar atmosphere at a rotational speed of 200 rpm to obtain a mixture.

[0049] (4) Preparation of an as-cast AMC: 970 g of an AA6111 aluminum alloy melt was heated to 700° C., the mixture of the copper-coated graphene and the aluminum powder was added to the aluminum alloy melt under mechanical stirring at 1,000 rpm for 5 min, and the resulting mixture was heated to 720° C., then subjected to an ultrasonic treatment at 1.5 kW for 50 s, and casted to obtain the as-cast AMC.

[0050] (5) Homogenization: The as-cast AMC was kept at 560° C. for 20 h.

[0051] (6) Rolling: A homogenized composite was rolled at 450° C. with a deformation amount of 84% to finally obtain the graphene and in-situ nano-ZrB.sub.2 particle-co-reinforced AMC.

[0052] The AMC co-reinforced with 0.1 wt. % graphene and 0.1 wt. % in-situ nano-ZrB.sub.2 particles prepared in this example had a strength of 427 MPa and an elongation of 16%, where the strength was increased by 14.8% and the elongation was reduced by 36% compared with the AMC co-reinforced with 0.01 wt. % graphene and 3 wt. % in-situ nano-ZrB.sub.2 particles prepared in Example 1.

[0053] Example 3: A preparation method of an AMC co-reinforced with 0.1 wt. % graphene and 3 wt. % in-situ nano-ZrB.sub.2 particles was provided in this example, which was as follows:

[0054] (1) Pretreatment of raw materials for producing the 3 wt. % ZrB.sub.2 particles: 97.8 g of potassium fluoroborate and 91.2 g of potassium fluorozirconate were taken and thoroughly mixed, and then preheated to 300° C. for later use.

[0055] (2) Preparation of copper-coated graphene through a chemical plating process: surface treatment of graphene: 1 g of graphene was subjected to ultrasonic dispersion in 1 L of deionized water for 50 min to obtain a 1 g/L graphene dispersion, a reagent was added to the graphene dispersion to prepare a sensitizing solution (30 g of SnCl.sub.2.Math.2H.sub.2O and 50 mL of 37 wt. % HCl), and the sensitizing solution was stirred at 25° C. for 50 min to allow a sensitization treatment; sensitized graphene was filtered out, washed, and added to 1 L of a 10 g/L AgNO.sub.3 solution, 12 mL of aqueous ammonia was slowly injected until the solid was completely dissolved, and the resulting mixture was stirred at room temperature for 50 min to allow activation; sensitized and activated graphene was filtered out, washed, and added to a 20 g/L sodium hypophosphite solution, and the resulting mixture was subjected to an ultrasonic treatment for 3 min, and allowed to stand at room temperature for 1 min to remove the residual activation solution on a surface of the graphene; and the graphene was filtered out, rinsed with distilled water until neutral, and dried at 60° C. for later use; and

[0056] the graphene obtained after the surface treatment was subjected to ultrasonic dispersion in 1 L of deionized water for 3 min, and a chemical reagent was added to prepare a chemical plating solution (15 g of CuSO.sub.4.Math.5H.sub.2O, 20 g of C.sub.4O.sub.6H.sub.4Kna, and 25 g of EDTA-2Na); the chemical plating solution was heated to 60° C., 15 mL of a formaldehyde solution was added dropwise to the chemical plating solution to allow reduction for 3 min, and then 30 mL of the formaldehyde solution was added, during which a 37 wt. % NaOH solution was added dropwise to the chemical plating solution at a rate of 2 mL/3 min to maintain a pH of the chemical plating solution at 11.5 to 12, where the entire reduction process from the beginning of the dropwise addition of the NaOH solution to the end of the dropwise addition of the NaOH solution was controlled within 40 min; a product was filtered out, washed with pure water until neutral, and subjected to passivation with a passivation solution for 15 min; and a passivated product was washed with absolute ethanol until neutral, and then dried to obtain a copper-coated graphene nanosheet.

[0057] (3) Mixing of the copper-coated graphene and an aluminum powder: 8 g of the copper-coated graphene and 16 g of the aluminum powder with a particle size of 20 μm were mixed and ball-milled for 1 h in a ball mill under an Ar atmosphere at a rotational speed of 200 rpm to obtain a mixture.

[0058] (4) Preparation of an as-cast AMC: 970 g of an AA6111 aluminum alloy melt was heated to 850° C., the pretreated potassium fluoroborate and potassium fluorozirconate were added to allow a reaction for 25 min to produce ZrB.sub.2 particles, during which EMS was conducted at 10 Hz for particle dispersion; the resulting reaction system was cooled to 700° C., and the mixture of the copper-coated graphene and the aluminum powder was added to the aluminum alloy melt under mechanical stirring at 1,000 rpm for 5 min; and the resulting mixture was heated to 720° C., then subjected to an ultrasonic treatment at 1.5 kW for 50 s, and casted to obtain the as-cast AMC.

[0059] (5) Homogenization: The as-cast AMC was kept at 560° C. for 20 h.

[0060] (6) Rolling: A homogenized composite was rolled at 450° C. with a deformation amount of 84% to finally obtain the graphene and in-situ nano-ZrB.sub.2 particle-co-reinforced AMC.

[0061] The AMC co-reinforced with 0.1 wt. % graphene and 3 wt. % in-situ nano-ZrB.sub.2 particles prepared in this example had a strength of 474 MPa and an elongation of 15%, where the strength was increased by 27.4% and the elongation was reduced by 40% compared with the AMC co-reinforced with 0.01 wt. % graphene and 3 wt. % in-situ nano-ZrB.sub.2 particles prepared in Example 1; and the strength was increased by 11% and the elongation was reduced by 6.7% compared with the AMC co-reinforced with 0.1 wt. % graphene and 0.1 wt. % in-situ nano-ZrB.sub.2 particles prepared in Example 2.

[0062] FIG. 2 shows scanning patterns of a microstructure in a rolling state, where (a) shows a surface parallel to a stress surface in a rolling direction (RD-TD surface) and (b) shows a surface parallel to a side surface in the rolling direction (RD-ND surface). It can be seen from the figure that the graphene and in-situ nano-ZrB.sub.2 particles coexist in the aluminum matrix. The AMC co-reinforced with 0.1 wt. % graphene and 3 wt. % in-situ nano-ZrB.sub.2 particles prepared in this example has high strength and high plasticity.