Nanoscale in-situ TiB2 reinforced Al-Zn-Mg-Cu composite material and preparation method thereof

Abstract

The invention discloses a TiB2 particle reinforced Al-Zn-Mg-Cu composite material system and a preparation method of the TiB2 particle reinforced Al-Zn-Mg-Cu composite material system. A Ti modified in-situ TiB2 / Al intermediate alloy is prefabricated, a TiB2 at-Al3Ti core-shell structure which is well combined with an Al matrix interface and is not prone to growth is constructed, a good TiB2 at-Al3Ti / Al coherent interface is formed, the interface mismatch degree is reduced to 2% from 6%, and the size of a reinforced phase is kept between 10 nm and 200 nm. And meanwhile, the TiB2 particle reinforced Al-Zn-Mg-Cu composite material is prepared through a two-step method, and the problem that Mg, Zn and Cu elements are burnt out and oxidized due to the fact that the in-situ reaction of KBF4 and K2TiF6 is not matched with the aluminum alloy smelting temperature interval is solved. The TiB2 / Al interface bonding in the TiB2 particle reinforced Al-Zn-Mg-Cu composite material prepared through the method is good, compared with a composite material prepared through a traditional technology, the elasticity modulus is improved by 15-40%, the tensile property is improved by 10% or above compared with the composite material prepared through the traditional technology, the good fatigue performance larger than or equal to 260 MPa is achieved, and the requirements for light weight and high strength of components are better met.

Description

Technical Field

[0001] This invention relates to nanoparticle-reinforced aluminum-based composite materials, specifically to a nanoscale in-situ TiB2-reinforced Al-Zn-Mg-Cu composite material and its preparation method. Background Technology

[0002] Particle-reinforced Al-Zn-Mg-Cu composites possess low density, high specific strength, and good plasticity, making them promising for applications in aerospace, rail transportation, and advanced agricultural machinery. Compared to other nano-reinforcing phases, TiB2 particles exhibit extremely high elastic modulus (approximately 530 GPa). Therefore, the addition of TiB2 significantly enhances the elastic modulus of aluminum matrix composites, resulting in TiB2 / Al composites with good stiffness and wear resistance. Simultaneously, the dispersed distribution of TiB2 particles increases the resistance to fatigue crack propagation, significantly improving the fatigue strength of aluminum matrix composites. Currently, the mainstream preparation process for TiB2-reinforced aluminum matrix composites involves first ball milling TiB2 powder and aluminum alloy powder together, followed by hot pressing sintering or spark plasma sintering to form the mixture. For example, CN201610099212.9 discloses a method for preparing titanium boride particle-reinforced aluminum matrix composites using spark plasma sintering. This method uses ball milling followed by spark plasma sintering to prepare 1XXX Al composites with a TiB2 mass fraction of 10%-20%, achieving a hardness of 65-85 HV. However, this method suffers from TiB2 particle agglomeration and powder oxidation, leading to a weakened strengthening effect. Furthermore, commercially available TiB2 powder typically contains particles at the micrometer scale, resulting in poor interfacial bonding with the Al matrix and limited strengthening effect, making it difficult to further improve the performance of TiB2 / Al composites.

[0003] In-situ reaction is a novel process for introducing nano-TiB2 phase into aluminum-based composite materials. This method involves adding powders composed of Ti, TiO2, and H3BO3 to the aluminum alloy melt for a melt self-propagating reaction, or adding a mixed salt composed of KBF4 and K2TiF6, to generate TiB2 particles through in-situ reaction. Compared to ball milling, the TiB2 particles generated by the in-situ reaction method have finer particle sizes and better TiB2 / Al interfaces, resulting in superior strengthening effects. For example, CN201610849631.X discloses an ultra-high strength, high hardness TiB2 particle-reinforced Al-Zn-Mg-Cu composite material and its preparation method. A TiB2 / Al master alloy was prepared using a melt self-propagating synthesis method, and a TiB2 / Al-Zn-Mg-Cu composite material was further prepared. For example, CN201610199991.X discloses an aluminum-based composite material for aero-engine blades. By using a mixed salt of KBF4 and K2TiF6 in situ reaction, 5% TiB2 particles by mass fraction are introduced into the Al-Zn-Mg-Cu alloy, so that the aluminum-based composite material has an elastic modulus of 75 GPa and a tensile strength of 700 MPa.

[0004] However, due to the inherent lattice parameter differences between TiB2 and Al, TiB2 prepared by in-situ reaction still exhibits a lattice mismatch of up to 6% with the Al matrix even under optimal orientation, leading to severe stress concentration at the TiB2 / Al interface. Furthermore, the current melt self-propagating method can only control the TiB2 particle size to slightly less than 1 μm, which is still insufficient to produce a adequate strengthening effect. In addition, to achieve optimal thermodynamic and kinetic conditions for the in-situ reaction, the reaction temperature should be controlled at 800℃-900℃ and held at this temperature for a relatively long time. Under these conditions, high vapor pressure and highly reactive metal components such as Zn, Mg, and Cu are prone to oxidation and burn-off, resulting in deviations in the composition of the aluminum-based composite material. Summary of the Invention

[0005] To address the problems of high interfacial mismatch, large TiB2 particle size, and mismatch between the in-situ reaction temperature range and aluminum alloy melting temperature range in traditional in-situ reaction methods for preparing TiB2 / Al, this invention designs a TiB2 / Al master alloy modified with trace amounts of Ti and a two-step method for preparing TiB2 / Al-Zn-Mg-Cu composite materials. First, a TiB2 / Al master alloy modified with trace amounts of Ti is prepared. Nanoscale TiB2 particles are then prepared through an in-situ reaction using a mixed salt of KBF4 and K2TiF6. Ti modification is then used to construct a TiB2@Al3Ti core-shell structure with good interfacial compatibility with the Al matrix and low growth rate. Subsequently, the aforementioned master alloy is added during the Al-Zn-Mg-Cu alloy melting process to complete the preparation of the TiB2 / Al-Zn-Mg-Cu composite material. The aluminum-based composite material prepared using the above-mentioned technical route allows α-Al to nucleate and grow on the TiB2@Al3Ti core-shell structure during solidification, forming a good TiB2@Al3Ti / Al coherent interface, reducing the interface mismatch from 6% to 2%. At the same time, the core-shell structure has high coarsening resistance, keeping the TiB2@Al3Ti particle size within 10-200 nm without growth. In addition, the in-situ reaction is separated from the alloy melting process, avoiding the high-temperature environment of the in-situ reaction that leads to the burn-off and oxidation of Mg, Zn, and Cu elements, and significantly improving the composition control accuracy of the TiB2 / Al-Zn-Mg-Cu composite material.

[0006] This invention is achieved through the following technical solution: A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 4.5-8.5%, Mg 2.0-4.0%, Cu 0.8-2.2%, Ti 0.03-0.5%, TiB2 0.5-10.0%, with the balance being Al. TiB2 is an intermediate alloy with a TiB2@Al3Ti core-shell structure. During the preparation of the composite material, TiB2 is introduced through in-situ reaction of KBF4 and K2TiF6. The mass fraction of TiB2 in the master alloy is 5-15%, and the mass fraction of Ti is 0.03-0.5%.

[0007] This invention also discloses a method for preparing TiB2 particle-reinforced Al-Zn-Mg-Cu composite materials, comprising the following steps: (A) Preparation of Ti-modified TiB2 / Al master alloy with TiB2@Al3Ti core-shell structure: (1) Heat the resistance furnace to 450°C and load the aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 800-900℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 0.5-2h with stirring on, and the TiB2 production is controlled to be 5-15%; (3) Cool down to 700-800℃, add Al-Ti master alloy under stirring, control the mass fraction of Ti in the melt to be 0.03-0.5%, and the generated Al3Ti adheres to TiB2 particles to form a TiB2@Al3Ti core-shell structure; (4) After refining and removing slag, the melt is cast into a crystallizer to obtain a TiB2 / Al master alloy with a TiB2@Al3Ti core-shell structure.

[0008] Preferably, the purity of the aluminum ingot in step (1) is 99.5-99.99%.

[0009] Preferably, the stirring methods described in steps (2) and (3) include mechanical stirring and electromagnetic stirring.

[0010] Preferably, the crystallizer size in step (4) is Φ90-800mm.

[0011] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load the aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 720-760℃, and Al-Cu and Al-Ti master alloys are added; (3) With stirring on, add the Ti-modified TiB2 / Al master alloy prepared in step (A), and control the mass fraction of TiB2 in the melt to be 2.0-8.0%; (4) Cool down to 700-740℃ and add Zn and Mg components; (5) After refining and slag removal, the melt is cast into a crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0012] Preferably, the purity of the aluminum ingot in step (1) is 99.5-99.99%.

[0013] Preferably, the stirring method described in step (3) includes mechanical stirring and electromagnetic stirring.

[0014] Preferably, the addition of Zn and Mg components in step (4) includes pure metals and intermediate alloys.

[0015] Preferably, the crystallizer size in step (5) is Φ90-800mm.

[0016] Beneficial effects (1) The present invention designs nano-sized TiB2 particles with high modulus as a reinforcing phase, which significantly improves the elastic modulus of aluminum matrix composites, thereby improving the stiffness and wear resistance of the components; TiB2 particles increase the resistance to fatigue crack propagation, thereby significantly improving the fatigue strength of aluminum matrix composites.

[0017] (2) This invention constructs a TiB2@Al3Ti core-shell structure with extremely low mismatch with the Al matrix and is not easy to grow by in situ reaction of KBF4 and K2TiF6 and modification with trace amount of Ti. The TiB2@Al3Ti / Al coherent interface is formed, which improves the interfacial bonding between TiB2 and Al matrix and keeps the size of the reinforcing phase at 10-200nm.

[0018] (3) The present invention prepares Ti modified TiB2 / Al master alloy and TiB2 / Al-Zn-Mg-Cu composite material by two steps, avoiding the problem of Mg, Zn and Cu element burn-off and oxidation caused by the in-situ reaction of KBF4 and K2TiF6 and the mismatch of casting temperature range of Al-Zn-Mg-Cu alloy.

[0019] (4) The Ti-modified TiB2 / Al master alloy and TiB2 / Al-Zn-Mg-Cu composite material in this invention use ordinary smelting, refining and casting equipment, which have the advantages of simple process, high production efficiency and low cost, and are suitable for large-scale industrial production. Attached Figure Description

[0020] Figure 1 A schematic diagram of the TiB2@Al3Ti core-shell structure and the construction of the TiB2@Al3Ti / Al coherent interface. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in detail below. These embodiments are implemented based on the technical solution of the present invention, and detailed implementation schemes and specific operation processes are given. However, the protection scope of the present invention is not limited to the embodiments described.

[0022] Example 1 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 5.5%, Mg 2.8%, Cu 1.6%, Ti 0.2%, TiB2 5.0%, with the balance being Al.

[0023] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of Ti-modified TiB2 / Al master alloy with TiB2@Al3Ti core-shell structure: (1) Heat the resistance furnace to 450°C and load 99.5% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 860℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1 hour under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 10%; (3) Cool down to 750℃, add Al-Ti master alloy under electromagnetic stirring, and control the mass fraction of Ti in the melt to be 0.2%; (4) After refining and removing slag, the melt is cast into a Φ178mm crystallizer to obtain Ti-modified TiB2 / Al master alloy.

[0024] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.5% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 740°C and Al-Cu and Al-Ti master alloys are added; (3) Under the condition of turning on the electromagnetic stirring, add the Ti-modified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 5.0%; (4) Cool down to 700℃ and add pure Zn ingot and pure Mg ingot; (5) After refining and slag removal, the melt is cast into a Φ178mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0025] Example 2 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 6.5%, Mg 2.4%, Cu 1.8%, Ti 0.3%, TiB2 4.5%, with the balance being Al.

[0026] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of Ti-modified TiB2 / Al master alloy with TiB2@Al3Ti core-shell structure: (1) Heat the resistance furnace to 450°C and load 99.9% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 850°C, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1 hour under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 5%; (3) Cool down to 740℃, add Al-Ti master alloy under electromagnetic stirring, and control the mass fraction of Ti in the melt to be 0.3%; (4) After refining and removing slag, the melt is cast into a Φ178mm crystallizer to obtain Ti-modified TiB2 / Al master alloy.

[0027] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.9% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 720°C and Al-Cu and Al-Ti master alloys are added; (3) Under the condition of turning on the electromagnetic stirring, add the Ti-modified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 4.5%; (4) Cool down to 700℃ and add Al-Zn and Al-Mg master alloys; (5) After refining and slag removal, the melt is cast into a Φ508mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0028] Example 3 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 6.2%, Mg 2.2%, Cu 1.5%, Ti 0.15%, TiB2 6.5%, with the balance being Al.

[0029] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of Ti-modified TiB2 / Al master alloy with TiB2@Al3Ti core-shell structure: (1) Heat the resistance furnace to 450°C and load 99.9% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 850℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1.5h under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 15%; (3) Cool down to 740℃, add Al-Ti master alloy under electromagnetic stirring, and control the mass fraction of Ti in the melt to be 0.2%; (4) After refining and removing slag, the melt is cast into a Φ90mm crystallizer to obtain Ti-modified TiB2 / Al master alloy.

[0030] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.95% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 720°C and Al-Cu and Al-Ti master alloys are added; (3) With mechanical stirring on, add the Ti-modified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 6.5%; (4) Cool down to 700℃ and add Al-Zn and Al-Mg master alloys; (5) After refining and slag removal, the melt is cast into a Φ800mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0031] Example 4 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 5.5%, Mg 2.8%, Cu 1.6%, Ti 0.2%, TiB2 0.5%, with the balance being Al.

[0032] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of Ti-modified TiB2 / Al master alloy with TiB2@Al3Ti core-shell structure: (1) Heat the resistance furnace to 450°C and load 99.5% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 860℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1 hour under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 5%; (3) Cool down to 750℃, add Al-Ti master alloy under electromagnetic stirring, and control the mass fraction of Ti in the melt to be 0.03%; (4) After refining and removing slag, the melt is cast into a Φ178mm crystallizer to obtain Ti-modified TiB2 / Al master alloy.

[0033] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.5% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 740°C and Al-Cu and Al-Ti master alloys are added; (3) Under the condition of turning on the electromagnetic stirring, add the Ti-modified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 0.5%; (4) Cool down to 700℃ and add pure Zn ingot and pure Mg ingot; (5) After refining and slag removal, the melt is cast into a Φ178mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0034] Example 5 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 5.5%, Mg 2.8%, Cu 1.6%, Ti 0.2%, TiB2 10.0%, with the balance being Al.

[0035] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of Ti-modified TiB2 / Al master alloy with TiB2@Al3Ti core-shell structure: (1) Heat the resistance furnace to 450°C and load 99.5% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 860℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1 hour under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 15%; (3) Cool down to 750℃, add Al-Ti master alloy under electromagnetic stirring, and control the mass fraction of Ti in the melt to be 0.5%; (4) After refining and removing slag, the melt is cast into a Φ178mm crystallizer to obtain Ti-modified TiB2 / Al master alloy.

[0036] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.5% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 740°C and Al-Cu and Al-Ti master alloys are added; (3) Under the condition of turning on the electromagnetic stirring, add the Ti-modified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 10.0%; (4) Cool down to 700℃ and add pure Zn ingot and pure Mg ingot; (5) After refining and slag removal, the melt is cast into a Φ178mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0037] Comparative Example 1 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 5.5%, Mg 2.8%, Cu 1.6%, Ti 0.2%, TiB2 5.0%, with the balance being Al.

[0038] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (1) Heat the resistance furnace to 450°C and load 99.5% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 740°C, and Al-Cu and Al-Ti master alloys are added. After it is completely melted, pure Zn ingots and Mg ingots are added. (3) Heat to 860℃, add a mixed salt consisting of KBF4 and K2TiF6 directly to the melt, and keep it at this temperature for 1.5h with electromagnetic stirring on, controlling the TiB2 formation amount to 5%; (4) After refining and slag removal, the melt is cast into a Φ178mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0039] Comparative Example 2 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 6.5%, Mg 2.4%, Cu 1.8%, Ti 0.3%, TiB2 4.5%, with the balance being Al.

[0040] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of unmodified TiB2 / Al master alloy: (1) Heat the resistance furnace to 450°C and load 99.9% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 850°C, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1 hour under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 5%; (3) After refining and slag removal, the melt is cast into a Φ178mm crystallizer to obtain an unmodified TiB2 / Al master alloy.

[0041] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.9% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 720°C and Al-Cu and Al-Ti master alloys are added; (3) With the electromagnetic stirring turned on, add the unmodified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 4.5%; (4) Cool down to 700℃ and add Al-Zn and Al-Mg master alloys; (5) After refining and slag removal, the melt is cast into a Φ508mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0042] Comparative Example 3 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 6.2%, Mg 2.2%, Cu 1.5%, Ti 0.15%, TiB2 6.5%, with the balance being Al.

[0043] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of unmodified TiB2 / Al master alloy: (1) Heat the resistance furnace to 450°C and load 99.9% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 850℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1.5h under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 15%; (3) After refining and slag removal, the melt is cast into a Φ90mm crystallizer to obtain an unmodified TiB2 / Al master alloy.

[0044] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.95% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 720°C and Al-Cu and Al-Ti master alloys are added; (3) With mechanical stirring on, add the unmodified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 6.5%; (4) Cool down to 700℃ and add Al-Zn and Al-Mg master alloys; (5) After refining and slag removal, the melt is cast into a Φ800mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0045] Comparative Example 4 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 5.5%, Mg 2.8%, Cu 1.6%, Ti 0.2%, TiB2 0.5%, with the balance being Al.

[0046] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of unmodified TiB2 / Al master alloy: (1) Heat the resistance furnace to 450°C and load 99.9% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 850℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1.5h under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 5%; (3) After refining and slag removal, the melt is cast into a Φ90mm crystallizer to obtain an unmodified TiB2 / Al master alloy.

[0047] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.95% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 720°C and Al-Cu and Al-Ti master alloys are added; (3) With mechanical stirring on, add the unmodified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 0.5%; (4) Cool down to 700℃ and add Al-Zn and Al-Mg master alloys; (5) After refining and slag removal, the melt is cast into a Φ800mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0048] Comparative Example 5 A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system comprises the following components by mass percentage: Zn 5.5%, Mg 2.8%, Cu 1.6%, Ti 0.2%, TiB2 10.0%, with the balance being Al.

[0049] A method for preparing a TiB2 particle-reinforced Al-Zn-Mg-Cu composite material includes the following steps: (A) Preparation of unmodified TiB2 / Al master alloy: (1) Heat the resistance furnace to 450°C and load 99.9% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 850℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 1.5h under the condition of turning on the electromagnetic stirring, and the TiB2 generation is controlled to be 15%; (3) After refining and slag removal, the melt is cast into a Φ90mm crystallizer to obtain an unmodified TiB2 / Al master alloy.

[0050] (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (1) Heat the resistance furnace to 450°C and load 99.95% pure aluminum ingots into the resistance furnace; (2) After the aluminum ingot is completely melted, the temperature is raised to 720°C and Al-Cu and Al-Ti master alloys are added; (3) Under the condition of mechanical stirring, add the unmodified TiB2 / Al master alloy prepared in step (A) and control the mass fraction of TiB2 in the melt to be 10%; (4) Cool down to 700℃ and add Al-Zn and Al-Mg master alloys; (5) After refining and slag removal, the melt is cast into a Φ800mm crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

[0051] In the examples, the size of the Ti-modified TiB2 / Al master alloy reinforcing phase in the TiB2@Al3Ti core-shell structure was maintained between 10-200 nm. In the comparative example, the size of the unmodified TiB2 / Al master alloy TiB2 was approximately 1 μm.

[0052] Table 1 compares the mechanical properties of the TiB2 / Al-Zn-Mg-Cu composite materials prepared in the examples and comparative examples. The mechanical properties were tested using an MTS C43 electronic universal testing machine.

[0053] The test method for elastic modulus is as follows: according to GB / T 228.1 standard, the test is carried out using an MTS C43 electronic universal testing machine, and the slope of the elastic segment of the tensile curve is measured as the elastic modulus.

[0054] The calculation formula is: Where E is the elastic modulus of the TiB2-reinforced aluminum matrix composite, ωvol(Al) and ωvol(TiB2) are the volume fractions of Al and TiB2 in the composite, respectively, and w(TiB2) is the mass fraction of TiB2 in the composite. The fatigue strength test method is as follows: According to GB / T 3075 standard, the INSTRON 8801 fatigue testing machine is used for testing, which can be cycled 10 times. 7 The maximum stress that prevents fracture after a certain number of cycles is the fatigue strength.

[0055] Table 1 Comparison of mechanical properties between the examples and comparative examples Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system, characterized in that, The alloy comprises the following components by mass percentage: Zn 4.5-8.5%, Mg 2.0-4.0%, Cu 0.8-2.2%, Ti 0.03-0.5%, TiB2 0.5-10.0%, with the balance being Al. TiB2 is an intermediate alloy with a TiB2@Al3Ti core-shell structure.

2. The TiB2 particle-reinforced Al-Zn-Mg-Cu composite material system according to claim 1, characterized in that, TiB2 is introduced through in-situ reaction of KBF4 and K2TiF6. The mass fraction of TiB2 in the master alloy is 5-15%, and the mass fraction of Ti is 0.03-0.5%.

3. A method for preparing the TiB2 particle-reinforced Al-Zn-Mg-Cu composite material according to claim 1, characterized in that, Includes the following steps: (A) Preparation of Ti-modified TiB2 / Al master alloy with TiB2@Al3Ti core-shell structure: (A1) Heat the resistance furnace to 450°C and load the aluminum ingots into the resistance furnace; (A2) After the aluminum ingot is completely melted, the temperature is raised to 800-900℃, a mixed salt consisting of KBF4 and K2TiF6 is added, and the temperature is maintained for 0.5-2 hours with stirring, controlling the TiB2 formation amount to 5-15%; (A3) Cool to 700-800℃, add Al-Ti master alloy while stirring, and control the mass fraction of Ti in the melt to be 0.03-0.5%; (A4) After refining and slag removal, the melt is cast into a crystallizer to obtain a Ti-modified TiB2 / Al master alloy; (B) Preparation of TiB2 / Al-Zn-Mg-Cu composite material: (B1) Heat the resistance furnace to 450°C and load the aluminum ingots into the resistance furnace; (B2) After the aluminum ingot is completely melted, the temperature is raised to 720-760℃, and Al-Cu and Al-Ti master alloys are added; (B3) With stirring on, add the Ti-modified TiB2 / Al master alloy prepared in step (A), and control the mass fraction of TiB2 in the melt to be 2.0-8.0%; (B4) Cool to 700-740℃ and add Zn and Mg components; (B5) After refining and slag removal, the melt is cast into a crystallizer to obtain TiB2 / Al-Zn-Mg-Cu composite material.

4. The method for preparing the TiB2 particle-reinforced Al-Zn-Mg-Cu composite material according to claim 3, characterized in that, In step (A1), the purity of the aluminum ingot is 99.5-99.99%.

5. The method for preparing the TiB2 particle-reinforced Al-Zn-Mg-Cu composite material according to claim 3, characterized in that, The stirring method in steps (A2) and (A3) is mechanical stirring or electromagnetic stirring.

6. The method for preparing the TiB2 particle-reinforced Al-Zn-Mg-Cu composite material according to claim 3, characterized in that, In step (A4), the crystallizer size is Φ90-800mm.

7. The method for preparing the TiB2 particle-reinforced Al-Zn-Mg-Cu composite material according to claim 3, characterized in that, In step (B1), the purity of the aluminum ingot is 99.5-99.99%.

8. The method for preparing the TiB2 particle-reinforced Al-Zn-Mg-Cu composite material according to claim 3, characterized in that, The stirring method in step (B3) is mechanical stirring or electromagnetic stirring.

9. The method for preparing the TiB2 particle-reinforced Al-Zn-Mg-Cu composite material according to claim 3, characterized in that, In step (B4), the Zn and Mg components are added as pure metals or intermediate alloys.

10. The method for preparing the TiB2 particle-reinforced Al-Zn-Mg-Cu composite material according to claim 3, characterized in that, In step (B5), the crystallizer size is Φ90-800mm.

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