A method for preparing high-modulus, high-strength, and high-fatigue-resistant aluminum-based composite plate

Abstract

The present invention provides a method for preparing a high-modulus, high-strength, and high-fatigue-resistant aluminum-based composite sheet. The method comprises subjecting an in-situ ceramic particle-reinforced aluminum-based composite material to a sequential semi-continuous casting, hot rolling, cold rolling, solution treatment, cold rolling, and aging treatment. The method for preparing the aluminum-based composite sheet provided by the present invention features a simple and rational process. The non-uniform distribution of in-situ ceramic particles forms a two-stage heterogeneous structure with a non-uniform grain distribution, achieving a multi-layered reinforcement structure and a microstructure that inhibits fatigue crack propagation. This method simultaneously improves the elastic modulus, tensile strength, fatigue limit strength, and fatigue crack propagation resistance of the aluminum-based composite sheet, and can be industrially produced using existing industrial equipment.

Description

Technical Field

[0001] The present invention relates to an aluminum-based composite material, in particular to an aluminum-based composite plate with improved modulus, strength and fatigue resistance, belonging to the technical field of aluminum alloy materials. Background Art

[0002] Aluminum alloy is one of the primary structural materials in aviation. With the advancement of lightweight and safety design concepts in the aviation industry, higher demands are being placed on high-performance aluminum alloys. The development of aluminum-based materials that combine high modulus, high strength, long fatigue life, and high resistance to fatigue crack growth is of great practical significance to the development of advanced aviation structural materials.

[0003] Commonly used strengthening measures for aluminum alloys mainly include grain boundary strengthening, dispersed phase strengthening, solute atom strengthening and dislocation strengthening, but these methods have certain limitations. First, these strengthening methods are difficult to improve the elastic modulus of aluminum alloys. Secondly, the stacking fault energy of aluminum alloys is high, which makes the plate prone to recrystallization and grain growth during rolling and subsequent heat treatment, resulting in overall low strength of aluminum alloy plates and low fatigue life. Finally, although grain refinement, increasing dispersed phase content and dislocation density can improve the strength of aluminum alloy materials, these methods inevitably lead to an increase in the fatigue crack growth rate of aluminum alloy materials. In short, the current aluminum alloy plate strength is low, and it is impossible to prepare aluminum alloy materials with simultaneous improvements in elastic modulus, strength and fatigue properties through alloying methods.

[0004] In addition, although aluminum-based composites with better performance can be prepared by in-situ formation of fine, high-modulus ceramic particles in aluminum alloys, the presence of ceramic particles in aluminum alloys will also refine the grains and increase dislocations, reducing the blunting and deflection effects of fatigue crack tips, resulting in the fatigue crack growth rate of particle-reinforced aluminum-based composites being higher than that of the corresponding matrix aluminum alloy.

[0005] It can be seen that adding ceramic particles to aluminum alloys to prepare aluminum-based composites can solve the problem of simultaneously improving strength and elastic modulus, but it will lead to an increase in the fatigue crack growth rate, which is not conducive to the safety design of components. It is urgent to design a new microstructure of aluminum-based composites to simultaneously achieve the simultaneous improvement of elastic modulus, tensile strength, fatigue limit strength and fatigue crack growth resistance. Summary of the Invention

[0006] In view of the problem that existing technologies are difficult to break through the problem of simultaneously improving the elastic modulus, strength and fatigue resistance of aluminum alloys, the purpose of the present invention is to provide a technical method with industrial production conditions to simultaneously improve the modulus, strength, fatigue limit strength of aluminum alloys and reduce the fatigue crack growth rate.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing high-modulus, high-strength, and high-fatigue-resistant aluminum-based alloy composite sheet material utilizes an in-situ autogenous method to prepare a ceramic particle-reinforced aluminum-based composite material. Through plastic deformation, heat treatment, and other steps, the non-uniform distribution of the reinforced particles and grain size is regulated, ultimately achieving improved modulus and strength while increasing fatigue life and reducing fatigue crack growth rate. Specifically, the preparation method comprises the following steps:

[0009] (1) preparing a TiB2 particle-reinforced aluminum-based composite melt, wherein the TiB2 particles have a size range of 20-2000 nm and a mass fraction of the TiB2 particles of 2-10% of the mass of the aluminum-based composite;

[0010] (2) Preparation of composite ingots: Preparation of TiB2 particle reinforced aluminum matrix composite ingots using semi-continuous casting technology;

[0011] (3) homogenization annealing: the ingot is subjected to homogenization annealing and then air-cooled;

[0012] (4) The ingot is subjected to heat preservation, hot rolling, and a single-pass pressing amount of 5-25% to reduce the thickness by 50%, and then annealing treatment is performed, and then cold rolling is performed after air cooling, and the cold rolling deformation amount is 20%; then the ingot is returned to the furnace for heating and heat preservation treatment, and the temperature is kept at 400-420°C for 2-4 hours, and finally the plate is hot rolled to a predetermined thickness;

[0013] (5) Annealing the plate after treatment in step (4) at a temperature of 300-460° C. for a holding time of 0.5-6 h;

[0014] (6) air-cooling the plate treated in step (5) and then cold-rolling the plate to a target thickness, for example, 1.5-5 mm, with a deformation of 3-5% per pass during the cold rolling process; the ceramic particles in the cold-rolled plate are distributed in a band along the rolling direction, forming alternating distribution of particle-rich areas and particle-poor areas;

[0015] (7) annealing the plate after the cold rolling treatment in step (6) at a temperature of 200-350° C. for a holding time of 1-4 h;

[0016] (8) subjecting the plate of step (7) to solution treatment, wherein the solution treatment includes heating, holding, and water quenching steps, followed by cold working deformation treatment at room temperature, with a transfer time interval of less than or equal to 1 hour, a deformation amount of 5%-30%, and a final average aspect ratio of the grain morphology greater than or equal to 2, preferably, an average aspect ratio of the grain morphology of 2-6;

[0017] (9) The plate subjected to the cold working deformation treatment described in step (8) is subjected to aging treatment.

[0018] Preferably, the specific process of the semi-continuous casting technology in step (2) is as follows: the holding temperature of the TiB2 particle reinforced aluminum-based composite material melt is 750-900°C, when the melt solidifies at the graphite ring, the ingot head descends, and the cooling water is turned on to cool the ingot, the ingot head descends at a speed of 10-30 mm / min, the water temperature of the ingot cooling water is 40-60°C, as the ingot head descends, the ingot slowly enters the heating furnace for annealing, the annealing temperature is 300-400°C, and a composite material ingot is obtained; through this step, 20-50wt.% TiB2 particles in the ingot microstructure are evenly distributed in the grains, and the remaining TiB2 particles are distributed along the grain boundaries.

[0019] Preferably, in step (3), the homogenization annealing temperature is 450-470°C and the holding time is 24-48 hours. Further preferably, the homogenization annealing treatment further comprises heating to 495°C after 30 minutes, holding for 12 hours, and then air cooling.

[0020] Preferably, in step (4), the holding temperature before hot rolling is 400-460° C., and the holding time is 2-6 h; the annealing temperature is 350-460° C., and the holding time is 2-6 h.

[0021] Preferably, in step (8), the solution treatment is a single-stage solution treatment or a double-stage solution treatment; the single-stage solution treatment is: heating to a temperature of 470-550°C and keeping it warm for 0.5-2h, followed by rapid quenching, and the transfer time is less than or equal to 15s; the double-stage solution treatment is: keeping it warm at 500°C for 20min and 505°C for 20min, followed by rapid quenching, and the transfer time is less than or equal to 15s.

[0022] Preferably, in step (9), the aging treatment is single-stage aging or double-stage aging; the single-stage aging temperature is 60-100°C, and the holding time is 48h-720h; the double-stage aging is a temperature of 180°C for 10-30min, and then a temperature of 100°C for 96-240h.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention provides a method for preparing a high-modulus, high-strength, high-fatigue-resistant aluminum-based composite plate, especially a large-size plate. By improving processes such as semi-continuous casting, rolling, and heat treatment, a dual heterogeneous structure with non-uniform ceramic particle distribution and non-uniform grain size distribution can be achieved, thereby improving the modulus, strength, and fatigue resistance of the aluminum alloy plate. The process method is simple and easy to operate, and the material preparation, processing, and heat treatment processes involved meet the conditions for industrial production. Among them, ceramic particles can improve the elastic modulus of the aluminum alloy; the strain gradient generated by the fine grains and coarse-fine grains formed by the ceramic particles and the particles can produce dispersion strengthening, grain boundary strengthening, and strain gradient strengthening, thereby improving the strength of the aluminum alloy; and the coarse grains with a specific aspect ratio can increase the plastic deformation capacity and the degree of fatigue crack path deflection. The ceramic particles can inhibit cracks from cracking along the slip band and increase crack deflection, thereby improving the plasticity of the aluminum alloy and reducing the fatigue crack growth rate, ultimately achieving the effect of improving the elastic modulus and strength of the aluminum alloy while reducing the fatigue crack growth rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The microstructure of the aluminum matrix composite plate reinforced with TiB2 particles. Figure 1 (a) is a SEM photograph of the microstructure of the plate prepared using the method of the present invention in Example 1, showing alternating distribution of particle-poor and particle-rich areas; Figure 1 (b) is the electron backscatter diffraction morphology of the plate prepared using the method of the present invention in Example 1, with coarse and fine grains distributed alternately. DETAILED DESCRIPTION

[0026] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0027] Example 1

[0028] (1) First, a mixed salt of NaBF4 and Na2TiF7 with a mass ratio of 2:1 was added to an aluminum melt at 850℃ and fully reacted for 30 minutes to generate TiB2 particles. At the same time, the melt was subjected to mechanical stirring and ultrasonic treatment at a stirring speed of 250 rpm and an ultrasonic intensity of 1500 W / m 2 , to achieve the generation of uniform TiB2 particles in the aluminum melt, with a size distribution range of 20-2000nm, and finally add Al-Cu master alloy, Al-Mn master alloy and pure Mg ingot according to the alloy element ratio to prepare Al-4.2Cu-1.8Mg-0.6Mn (mass fraction, %) composite material melt containing 2% TiB2 particles by mass.

[0029] (2) A 2wt.% TiB2 particle-reinforced Al-4.2Cu-1.8Mg-0.6Mn aluminum-based composite ingot is prepared using a semi-continuous casting technique. The equipment used in the semi-continuous casting technique is conventional equipment in the art. The specific process is as follows: The TiB2 particle-reinforced aluminum-based composite melt in step (1) is kept at a temperature of 750°C. After the melt solidifies at the graphite ring, the ingot head is lowered, and cooling water is turned on to cool the ingot. The ingot head descends at a speed of 30mm / min, and the temperature of the ingot cooling water is 40-60°C. As the ingot head descends, the ingot slowly enters a heating furnace for annealing at a temperature of 300°C. The resulting ingot has a cross-sectional size of 450×950mm. 20% of the TiB2 particles in the ingot are evenly distributed within the grains, and the remaining TiB2 particles are distributed along the grain boundaries.

[0030] (3) The ingot was subjected to homogenization annealing treatment at a temperature of 450°C for 24 h, then heated to 495°C for 30 min, kept at that temperature for 12 h, and then air-cooled; the cross-sectional dimensions of the ingot surface after milling were 420 × 920 mm;

[0031] (4) The ingot after homogenization annealing is hot rolled. Before rolling, it is kept at 400°C for 6 hours, with a reduction of 20-25% per pass. After multiple passes of rolling until the thickness is reduced by 50%, annealing is performed at 350°C. After keeping the temperature for 6 hours, it is air-cooled and then cold rolled. After the cold rolling deformation is 20%, it is returned to the furnace for heating and heat preservation. After keeping the temperature at 400°C for 4 hours, it is hot rolled to 6 mm.

[0032] (5) Then the 6 mm thick plate was annealed at 300 °C for 6 h;

[0033] (6) After air cooling, cold rolling is performed to a thickness of 1.5 mm, with a reduction of 3% per pass.

[0034] (7) The cold-rolled sheet was annealed at 350°C for 1 h.

[0035] (8) The plate was then subjected to a two-stage solution treatment process, with the solution treatment process being 500°C for 20 min and 505°C for 20 min, followed by rapid water quenching with a transfer time of less than 10 s; within 30 min, it was transferred to the rolling mill and cold rolled at room temperature to a thickness of 1.05 mm, a deformation of 30%, and an average aspect ratio of 2 in the plate grain morphology.

[0036] (9) Finally, the plate was subjected to a double-stage aging treatment with the process parameters of 180°C for 10 minutes and then 100°C for 240 hours.

[0037] The SEM microstructure and electron backscatter diffraction morphology of the obtained plate are as follows: Figure 1shown.

[0038] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the TiB2 particle reinforced Al-4.2Cu-1.8Mg-0.6Mn aluminum-based composite plate is 75GPa, the yield strength is 470MPa, the tensile strength is 610MPa, and the elongation is 16%. The fatigue limit strength at a stress ratio of 0.1 is 310MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 2.5×10 -4 mm / cycle.

[0039] Example 2

[0040] The method is basically the same as that of Example 1, except that the TiB2 particle content is 10 wt.%.

[0041] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the TiB2 particle reinforced Al-4.2Cu-1.8Mg-0.6Mn aluminum-based composite plate is 83GPa, the yield strength is 510MPa, the tensile strength is 640MPa, and the elongation is 14%. The fatigue limit strength at a stress ratio of 0.1 is 320MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 When the fatigue crack growth rate is 3×10 -4 mm / cycle.

[0042] Example 3

[0043] The method is basically the same as that of Example 1, except that in step (4), the plate is hot rolled to a thickness of 3 mm after being heated and kept in the furnace. In step (5), it is annealed at 350°C for 30 minutes; in step (6), it is air-cooled and then cold rolled to a thickness of 2.5 mm. The solid solution treatment in step (8) adopts a single-stage solid solution treatment, which is kept at 550°C for 0.5 hours and then water quenched. During the cold working deformation treatment, it is cold rolled at room temperature to a thickness of 2 mm, a deformation of 20%, and an average aspect ratio of 3 for the grain morphology. The process parameters for the double-stage aging treatment of the plate are to keep it at 180°C for 30 minutes and then keep it at 100°C for 96 hours.

[0044] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the TiB2 particle reinforced Al-4.2Cu-1.8Mg-0.6Mn aluminum-based composite plate is 75GPa, the yield strength is 450MPa, the tensile strength is 600MPa, and the elongation is 17%; the fatigue limit strength at a stress ratio of 0.1 is 300MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 When the fatigue crack growth rate is 2×10 -4 mm / cycle.

[0045] Example 4

[0046] (1) First, a 4 wt.% TiB2 particle-reinforced Al-6.5Zn-2.2Mg-2.2Cu (mass fraction, %) composite material melt was prepared using the method of Example 1, wherein the TiB2 particle size distribution range was 20-2000 nm.

[0047] (2) A 4 wt.% TiB2 particle-reinforced Al-6.5Zn-2.2Mg-2.2Cu aluminum-based composite ingot was prepared using a semi-continuous casting technique. The TiB2 particle-reinforced aluminum-based composite melt obtained in step (1) was held at a temperature of 900°C. After the melt solidified at the graphite ring, the ingot head was lowered, and cooling water was turned on to cool the ingot. The ingot head lowered at a speed of 10 mm / min, and the temperature of the ingot cooling water was 40-60°C. As the ingot head lowered, the ingot slowly entered a heating furnace for annealing at a temperature of 400°C. The resulting ingot had a cross-sectional size of 450×950 mm. 50% of the TiB2 particles in the ingot were evenly distributed within the grains, and the remaining TiB2 particles were distributed along the grain boundaries.

[0048] (3) The ingot was subjected to homogenization annealing at 470°C for 48 hours and then air-cooled. The cross-sectional dimensions of the ingot after milling were 420 × 920 mm.

[0049] (4) The ingot after homogenization annealing is hot rolled, kept at 460℃ for 2h before rolling, with a reduction of 5-10% per pass, and rolled to a thickness of ~200mm. It is then annealed at 460℃, kept at this temperature for 2h, and then air-cooled and cold-rolled to 160mm (cold rolling deformation of 20%). It is then returned to the furnace for heating and heat preservation treatment, kept at 420℃ for 2h, and then hot rolled to a thickness of 20mm.

[0050] (5) The 20 mm thick plate is annealed at 460°C for 1 hour.

[0051] (6) The plate is air-cooled and then cold-rolled to a thickness of 4.5 mm, with a reduction of 5% per pass.

[0052] (7) The cold-rolled sheet was annealed at a temperature of 200°C for 4 hours.

[0053] (8) The plate was then subjected to a single-stage solution treatment process, which included holding at 470°C for 2 h, followed by rapid water quenching with a transfer time of less than 10 s; it was transferred to the rolling mill within 60 min and cold rolled at room temperature to a thickness of 4.225 mm, a deformation of 5%, and an average aspect ratio of 3 for the grain morphology.

[0054] (9) Finally, the plate is subjected to a single-stage aging treatment with the process parameters of 100°C and 48h of insulation.

[0055] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the TiB2 particle reinforced Al-6.5Zn-2.2Mg-2.2Cu aluminum-based composite plate is 77GPa, the yield strength is 690MPa, the tensile strength is 750MPa, and the elongation is 15%. The fatigue limit strength at a stress ratio of 0.1 is 370MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 6.5×10 -4 mm / cycle.

[0056] Example 5

[0057] The method is basically the same as that of Example 4, except that the content of TiB2 particles in the aluminum-based composite material is 6 wt.%.

[0058] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the TiB2 particle reinforced Al-6.5Zn-2.2Mg-2.2Cu aluminum-based composite plate is 79GPa, the yield strength is 710MPa, the tensile strength is 765MPa, and the elongation is 13%; the fatigue limit strength at a stress ratio of 0.1 is 380MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 When the fatigue crack growth rate is 6.8×10 -4 mm / cycle.

[0059] Example 6

[0060] The method is basically the same as that of Example 4, except that: in step (6), the plate is air-cooled and then cold-rolled to a thickness of 5 mm. In step (8), it is cold-rolled at room temperature to a thickness of 4.5 mm, with a thickness deformation of 10% and a grain aspect ratio of 6. In step (9), the plate is subjected to a single-stage aging treatment with the process parameters of 60°C for 720 h.

[0061] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the TiB2 particle reinforced Al-6.5Zn-2.2Mg-2.2Cu (mass fraction) aluminum matrix composite plate is 77GPa, the yield strength is 700MPa, the tensile strength is 750MPa, and the elongation is 14%. The fatigue limit strength at a stress ratio of 0.1 is 360MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 When the fatigue crack growth rate is 6.6×10 -4 mm / cycle.

[0062] Comparative Example 1

[0063] The implementation steps of this comparative example are basically the same as those of Example 1, except that the heat treatment process adopts conventional aging treatment, that is, aging at 180° C. for 20 h.

[0064] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-4.2Cu-1.8Mg-0.6Mn aluminum matrix composite plate is 75GPa, the yield strength is 420MPa, the tensile strength is 570MPa, and the elongation is 12%. The fatigue limit strength at a stress ratio of 0.1 is 280MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 4×10 - 4 The elastic modulus of the material of this comparative example is the same as that of the example, but the strength, fatigue limit strength and fatigue crack growth resistance of this comparative example are lower than those of example 1.

[0065] Comparative Example 2

[0066] The implementation steps of this comparative example are basically the same as those of Example 1, except that, in step (4), no annealing treatment is performed during the hot rolling process of the aluminum-based composite material ingot.

[0067] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-4.2Cu-1.8Mg-0.5Mn aluminum matrix composite plate is 75GPa, the yield strength is 430MPa, the tensile strength is 590MPa, and the elongation is 16%. The fatigue limit strength at a stress ratio of 0.1 is 300MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 3.5×10 -4 The elastic modulus of the material of this comparative example is the same as that of the embodiment, but the elastic modulus, strength, fatigue limit strength and fatigue crack growth resistance of the material of this comparative example are lower than those of embodiment 1.

[0068] Comparative Example 3

[0069] The implementation steps of this comparative example are basically the same as those of Example 1, except that the annealing treatment in step (7) is not performed.

[0070] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-4.2Cu-1.8Mg-0.5Mn aluminum matrix composite plate is 75GPa, the yield strength is 400MPa, the tensile strength is 560MPa, and the elongation is 16%. The fatigue limit strength at a stress ratio of 0.1 is 260MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 3×10- 4 The elastic modulus of the material of this comparative example is the same as that of the embodiment, but the strength, fatigue limit strength and fatigue crack growth resistance are lower than those of the embodiment 1.

[0071] Comparative Example 4

[0072] The implementation steps of this comparative example are basically the same as those of Example 2, except that the heat treatment process adopts conventional aging treatment, that is, aging at 180° C. for 20 h.

[0073] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-4.2Cu-1.8Mg-0.6Mn aluminum matrix composite plate is 83GPa, the yield strength is 450MPa, the tensile strength is 585MPa, and the elongation is 10%. The fatigue limit strength at a stress ratio of 0.1 is 290MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 4.5×10 -4 The elastic modulus of the material of this comparative example is the same as that of the embodiment, but the strength, fatigue limit strength and fatigue crack growth resistance of the material of this comparative example are lower than those of the embodiment 2.

[0074] Comparative Example 5

[0075] The implementation steps of this comparative example are basically the same as those of Example 2, except that the aluminum-based composite material ingot is rapidly solidified, the TiB2 ceramic particles in the ingot are evenly distributed, and the grain size is evenly distributed.

[0076] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-4.2Cu-1.8Mg-0.6Mn aluminum matrix composite plate is 83GPa, the yield strength is 460MPa, the tensile strength is 600MPa, and the elongation is 12%. The fatigue limit strength at a stress ratio of 0.1 is 305MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 4×10 - 4 The elastic modulus of the material of this comparative example is the same as that of the example, but the strength, fatigue limit strength and fatigue crack growth resistance of this comparative example are lower than those of example 2.

[0077] Comparative Example 6

[0078] The implementation steps of this comparative example are basically the same as those of Example 2, except that no annealing treatment is used during the hot rolling process of the aluminum-based composite material ingot.

[0079] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-4.2Cu-1.8Mg-0.5Mn aluminum matrix composite plate is 83GPa, the yield strength is 440MPa, the tensile strength is 590MPa, and the elongation is 14%. The fatigue limit strength at a stress ratio of 0.1 is 285MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 3.8×10 -4 The elastic modulus of the material of this comparative example is the same as that of the embodiment, but the strength, fatigue limit strength and fatigue crack growth resistance of the material of this comparative example are lower than those of the embodiment 2.

[0080] Comparative Example 7

[0081] The implementation steps of this comparative example are basically the same as those of Example 2, except that the aluminum-based composite cold-rolled sheet is not annealed before solution treatment, and conventional aging treatment is used during aging, i.e., aging at 180° C. for 20 h.

[0082] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-4.2Cu-1.8Mg-0.5Mn aluminum matrix composite plate is 83GPa, the yield strength is 430MPa, the tensile strength is 570MPa, and the elongation is 12%. The fatigue limit strength at a stress ratio of 0.1 is 275MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 4.2×10 -4 The elastic modulus of the comparative material is the same as that of the example material, but the strength, fatigue limit strength and fatigue crack growth resistance of the comparative material are lower than those of Example 2.

[0083] Comparative Example 8

[0084] The implementation steps of this comparative example are basically the same as those of Example 1, except that the treatment object is Al-4.2Cu-1.8Mg-0.6Mn (mass fraction) alloy, no ceramic particles are added to the ingot, and conventional aging treatment is adopted, i.e., aging at 180°C for 20 hours.

[0085] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-4.2Cu-1.8Mg-0.6Mn aluminum matrix composite plate is 72GPa, the yield strength is 380MPa, the tensile strength is 510MPa, and the elongation is 14%. The fatigue limit strength at a stress ratio of 0.1 is 250MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 3.8×10 -4Compared with Example 1, the elastic modulus, strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 1.

[0086] Comparative Example 9

[0087] The implementation steps of this comparative example are basically the same as those of Example 4, except that conventional aging treatment is adopted, the aging temperature is 120° C., and the holding time is 20 h.

[0088] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 77GPa, the yield strength is 660MPa, the tensile strength is 690MPa, and the elongation is 12%. The fatigue limit strength at a stress ratio of 0.1 is 330MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 8.5×10 -4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 4.

[0089] Comparative Example 10

[0090] The implementation steps of this comparative example are basically the same as those of Example 4, except that the aluminum-based composite material ingot is prepared by rapid solidification assisted by an electromagnetic external field, and the TiB2 ceramic particles in the ingot are relatively evenly distributed and the grain size is evenly distributed.

[0091] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 77GPa, the yield strength is 640MPa, the tensile strength is 680MPa, and the elongation is 14%. The fatigue limit strength at a stress ratio of 0.1 is 320MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 7.5×10 -4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 4.

[0092] Comparative Example 11

[0093] The implementation steps of this comparative example are basically the same as those of Example 4, except that no annealing treatment is performed during the hot rolling process in step (4), but continuous hot rolling is performed to a thickness of 20 mm.

[0094] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 77GPa, the yield strength is 650MPa, the tensile strength is 685MPa, and the elongation is 13%. The fatigue limit strength at a stress ratio of 0.1 is 325MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 7.8×10 -4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 4.

[0095] Comparative Example 12

[0096] The implementation steps of this comparative example are basically the same as those of Example 4, except that the annealing treatment in step (7) is not performed.

[0097] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 77GPa, the yield strength is 620MPa, the tensile strength is 670MPa, and the elongation is 15%. The fatigue limit strength at a stress ratio of 0.1 is 300MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 7×10 - 4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 4.

[0098] Comparative Example 13

[0099] The implementation steps of this comparative example are basically the same as those of Example 5, except that conventional aging treatment is adopted, the aging temperature is 120° C., and the holding time is 20 h.

[0100] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 79GPa, the yield strength is 680MPa, the tensile strength is 710MPa, and the elongation is 10%. The fatigue limit strength at a stress ratio of 0.1 is 340MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 9×10 - 4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 5.

[0101] Comparative Example 14

[0102] The implementation steps of this comparative example are basically the same as those of Example 5, except that the aluminum-based composite material ingot is prepared by rapid solidification using an auxiliary electromagnetic external field, and the TiB2 ceramic particles in the ingot are uniformly distributed and the grain size is uniformly distributed.

[0103] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 79GPa, the yield strength is 660MPa, the tensile strength is 700MPa, and the elongation is 12%. The fatigue limit strength at a stress ratio of 0.1 is 335MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 8.5×10 -4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 5.

[0104] Comparative Example 15

[0105] The implementation steps of this comparative example are basically the same as those of Example 5, except that no annealing treatment is performed during the hot rolling process in step (4), but continuous hot rolling is performed to a thickness of 20 mm.

[0106] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 79GPa, the yield strength is 680MPa, the tensile strength is 710MPa, and the elongation is 11%. The fatigue limit strength at a stress ratio of 0.1 is 340MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 8×10 - 4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 5.

[0107] Comparative Example 16

[0108] The implementation steps of this comparative example are basically the same as those of Example 5, except that the annealing treatment in step (7) is not performed.

[0109] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 79GPa, the yield strength is 635MPa, the tensile strength is 690MPa, and the elongation is 12%. The fatigue limit strength at a stress ratio of 0.1 is 305MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 7.5×10 -4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 5.

[0110] Comparative Example 17

[0111] The implementation steps of this comparative example are basically the same as those of Example 4, except that the treatment object is Al-6.5Zn-2.2Mg-2.2Cu (mass fraction) alloy, and no ceramic particles are added to the ingot.

[0112] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 72GPa, the yield strength is 560MPa, the tensile strength is 620MPa, and the elongation is 14%. The fatigue limit strength at a stress ratio of 0.1 is 285MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 7×10 - 4 The elastic modulus, strength, fatigue limit strength and fatigue crack growth resistance of the material of this comparative example are lower than those of Example 4.

[0113] Comparative Example 18

[0114] The implementation steps of this comparative example are basically the same as those of Example 6, except that conventional aging treatment is adopted, the aging temperature is 120° C., and the holding time is 20 h.

[0115] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 77GPa, the yield strength is 660MPa, the tensile strength is 690MPa, and the elongation is 10%. The fatigue limit strength at a stress ratio of 0.1 is 320MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 8.5×10 -4When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 5.

[0116] Comparative Example 19

[0117] The implementation steps of this comparative example are basically the same as those of Example 6, except that the aluminum-based composite material ingot is prepared by rapid solidification assisted by an electromagnetic external field, and the TiB2 ceramic particles in the ingot are uniformly distributed and the grain size is uniformly distributed.

[0118] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 77GPa, the yield strength is 650MPa, the tensile strength is 690MPa, and the elongation is 13%. The fatigue limit strength at a stress ratio of 0.1 is 325MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 8×10 - 4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 6.

[0119] Comparative Example 20

[0120] The implementation steps of this comparative example are basically the same as those of Example 6, except that in step (4), no annealing and cold rolling treatment is performed during the rolling process, and continuous hot rolling is performed to the target thickness of 4.5 mm.

[0121] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 77GPa, the yield strength is 660MPa, the tensile strength is 690MPa, and the elongation is 12%. The fatigue limit strength at a stress ratio of 0.1 is 330MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 8.5×10 -4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 5.

[0122] Comparative Example 21

[0123] The implementation steps of this comparative example are basically the same as those of Example 6, except that the annealing treatment in step (7) is not performed.

[0124] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 77GPa, the yield strength is 620MPa, the tensile strength is 660MPa, and the elongation is 15%. The fatigue limit strength at a stress ratio of 0.1 is 300MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 7.5×10 -4 When the elastic modulus of the comparative example material is the same as that of the example material, the strength, fatigue limit strength and fatigue crack growth resistance of the comparative example material are lower than those of Example 6.

[0125] Comparative Example 22

[0126] The implementation steps of this comparative example are basically the same as those of Example 6, except that the treatment object is Al-6.5Zn-2.2Mg-2.2Cu (mass fraction) alloy, and no ceramic particles are added to the ingot.

[0127] Room temperature mechanical property tests along the rolling direction show that the elastic modulus of the Al-6.5Zn-2.2Mg-2.2Cu aluminum matrix composite plate is 72GPa, the yield strength is 520MPa, the tensile strength is 590MPa, and the elongation is 14%. The fatigue limit strength at a stress ratio of 0.1 is 260MPa, and the stress intensity factor range ΔK is 20MPa.m 0.5 The fatigue crack growth rate is 7.2×10 -4 The elastic modulus, strength, fatigue limit strength and fatigue crack growth resistance of the material of this comparative example are lower than those of Example 6.

[0128] The above describes specific embodiments of the present invention. By comparing the embodiments with comparative examples, the present invention provides a method for preparing large-scale high-modulus, high-strength, and high-fatigue-resistant aluminum-based composite material sheets, which can simultaneously improve the elastic modulus, tensile strength, fatigue limit strength, and fatigue crack growth resistance of the aluminum alloy sheet.

[0129] It should be understood that the present invention is not limited to the specific embodiments described above, and that those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of the present application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A method for preparing a high modulus, high strength, and high fatigue resistance aluminum-based alloy composite plate, characterized by: The preparation method comprises the following steps: (1) preparing a TiB2 particle reinforced aluminum matrix composite melt, wherein the TiB2 particle size ranges from 20 to 2000 nm, and the mass fraction of the TiB2 particles is 2 to 10% of the mass of the aluminum matrix composite; (2) Preparation of TiB2 particle reinforced aluminum matrix composite ingots using semi-continuous casting technology; (3) Homogenizing annealing: the ingot is subjected to homogenizing annealing and then air-cooled; (4) The ingot is subjected to heat preservation, hot rolling, and a single-pass pressing amount of 5-25% to reduce the thickness by 50%, and then annealing treatment is performed, and then cold rolling is performed after air cooling, and the cold rolling deformation amount is 20%; then the ingot is returned to the furnace for heating and heat preservation treatment, and the temperature is kept at 400-420℃ for 2-4 hours, and finally the plate is hot rolled to a predetermined thickness; (5) Annealing the plate after treatment in step (4) at a temperature of 300-460°C for a holding time of 0.5-6 hours; (6) air-cooling the plate treated in step (5) and then cold-rolling the plate to a target thickness, with the deformation of each pass being 3-5% during the cold rolling process; (7) Annealing the plate after cold rolling in step (6) at a temperature of 200-350°C for 1-4 hours; (8) subjecting the plate of step (7) to solution treatment, wherein the solution treatment includes heating, holding and water quenching steps, followed by cold working deformation treatment at room temperature, with a transfer time interval of less than or equal to 1 hour and a deformation amount of 5% to 30%; (9) The plate subjected to the cold working deformation treatment described in step (8) is subjected to aging treatment.

2. The preparation method according to claim 1, wherein: The specific process of step (2) is as follows: the holding temperature of the TiB2 particle reinforced aluminum-based composite material melt is 750-900°C, when the melt solidifies at the graphite ring, the ingot head is lowered, and the cooling water is turned on to cool the ingot, the ingot head descends at a speed of 10-30 mm / min, the temperature of the ingot cooling water is 40-60°C, and as the ingot head descends, the ingot slowly enters the heating furnace for annealing, the annealing temperature is 300-400°C, and a composite material ingot is obtained.

3. The preparation method according to claim 1, wherein: In step (3), the homogenization annealing temperature is 450-470°C, and the holding time is 24-48 hours.

4. The preparation method according to claim 3, wherein: The homogenization annealing treatment further includes heating to 495° C. after 30 minutes, keeping the temperature for 12 hours, and then air cooling.

5. The preparation method according to claim 1, wherein: In step (4), the holding temperature before hot rolling is 400-460°C, and the holding time is 2-6 hours; the annealing temperature is 350-460°C, and the holding time is 2-6 hours.

6. The preparation method according to claim 1, wherein: In step (8), the solution treatment is a single-stage solution treatment or a double-stage solution treatment; the single-stage solution treatment is: heating to a temperature of 470-550°C and keeping it warm for 0.5-2h, followed by rapid quenching, and the transfer time is less than or equal to 15s; the double-stage solution treatment is: keeping it warm at 500°C for 20min and 505°C for 20min, followed by rapid quenching, and the transfer time is less than or equal to 15s.

7. The preparation method according to claim 1, wherein: After the cold working deformation treatment in step (8), the average aspect ratio of the grain morphology is greater than or equal to 2.

8. The preparation method according to claim 1, wherein: After the cold working deformation treatment in step (8), the average aspect ratio of the grain morphology is 2-6.

9. The preparation method according to claim 1, wherein: In step (9), the aging treatment is single-stage aging or double-stage aging; the single-stage aging temperature is 60-100°C, and the holding time is 48h-720h; the double-stage aging is a temperature of 180°C for 10-30min, and then a temperature of 100°C for 96-240h.

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