Aluminum-based composite material for marine riser for deep sea drilling and preparation method and application of aluminum-based composite material

Abstract

The invention discloses an aluminum-based composite material for a deep sea drilling riser as well as a preparation method and application of the aluminum-based composite material. The preparation method comprises the following steps: S1, uniformly mixing aluminum alloy powder and AlCoCrFeNi high-entropy alloy powder through a tank mill; s2, the mixed powder is subjected to ball milling; s3, the ball-milled powder is dried and then put into a graphite mold to be subjected to cold pressing treatment, then vacuum sintering is conducted, and the sintering heating process comprises the steps that the temperature is increased to 250 DEG C within 150 minutes, and heat preservation is conducted for 1 hour; then the temperature is increased to 350 DEG C within 90 minutes, and heat preservation is conducted for 1 hour; raising the temperature to 450 DEG C within 90 minutes, and keeping the temperature for 1 hour; finally, the temperature is increased to 550-650 DEG C within 90 minutes, heat preservation is carried out for half an hour, cooling is carried out, and an aluminum-based composite material initial product is obtained; and S4, the aluminum-based composite material initial product is heated to 450 + / -10 DEG C for multi-pass rolling, the total deformation is controlled to be 20-80%, and the aluminum-based composite material for the deep sea drilling riser is obtained. The aluminum-based composite material prepared through the method has excellent compressive strength and corrosion resistance, and the service requirements of deep sea drilling riser and other extreme environments are met.

Description

Technical Field

[0001] This invention relates to the field of aluminum-based composite materials technology, and in particular to an aluminum-based composite material for deep-sea drilling risers, its preparation method, and its application. Background Technology

[0002] As offshore oil and gas resource development expands into deep and ultra-deep water, deep-sea drilling risers, as key equipment in deep-sea oil and gas development, must withstand extreme environments such as high pressure, high salinity, and dynamic loads. Traditional steel risers suffer from poor corrosion resistance and heavy weight, making it difficult to operate at depths exceeding 3000 meters, severely limiting the development of deep-sea drilling. Therefore, there is an urgent need to develop a new material suitable for manufacturing deep-sea drilling risers.

[0003] Aluminum-based composites possess lightweight, high strength, and corrosion resistance, making them promising candidates for manufacturing deep-sea drilling risers. However, existing aluminum-based composite manufacturing processes suffer from the following problems: First, the uneven distribution of reinforcing phases such as ceramic particles and carbon fibers leads to anisotropy in mechanical properties, affecting the material's service reliability; second, insufficient interfacial bonding strength between the reinforcing phases and the aluminum matrix affects load transfer efficiency, limiting the full realization of the material's strength potential; third, conventional processing methods struggle to simultaneously optimize both strength and corrosion resistance, often resulting in compromises; furthermore, the fatigue performance of the material under dynamic loads needs further improvement.

[0004] High entropy alloys (HEAs) possess high strength and toughness, excellent corrosion resistance, and good metal-metal interfacial bonding with aluminum matrices, holding promise for overcoming the performance bottlenecks of traditional aluminum-based composites. HEA particles, acting as reinforcing phases, can form a strong metallurgical bond with the aluminum matrix, exhibiting significant advantages. However, achieving a synergistic enhancement of both strength and corrosion resistance in the prepared high-performance aluminum-based composites remains challenging. This severely restricts the application of high-performance aluminum-based composites in harsh environments (such as deep-sea drilling risers). Summary of the Invention

[0005] In order to prepare an aluminum-based composite material suitable for use in deep-sea drilling risers, the present invention provides an aluminum-based composite material for use in deep-sea drilling risers.

[0006] The aluminum-based composite material for deep-sea drilling risers provided by this invention is prepared by the following method: S1. Aluminum alloy powder and AlCoCrFeNi high-entropy alloy powder are mixed evenly using a pot mill to obtain a mixed powder. The amount of AlCoCrFeNi high-entropy alloy powder is 5-15% of the mass of aluminum alloy powder.

[0007] S2. Place the mixed powder into a planetary ball mill, add anhydrous ethanol as a process control agent, and ball mill at 320 r / min for 24 hours to make the powder fine and uniform and mechanically alloyed.

[0008] S3, dry the ball-milled powder, then put it into a graphite mold for cold pressing treatment, and then vacuum sintering, the sintering temperature rising process is: rising to 250 DEG C within 150 minutes, keeping 1 hour at 250 DEG C; then rising to 350 DEG C within 90 minutes, keeping 1 hour; then rising to 450 DEG C within 90 minutes, keeping 1 hour; finally rising to 550-650 DEG C within 90 minutes, keeping half an hour, vacuum cooling, to obtain an aluminum matrix composite product.

[0009] S4, preheat the roller to 280±10 DEG C, then heat the aluminum matrix composite product to 450±10 DEG C and keep for 1-2 hours, then carry out multi-pass rolling, control the total deformation amount to be 20-80%, and the single-pass deformation amount is not more than 10%, to obtain an aluminum matrix composite material for deep-sea drilling riser.

[0010] Preferably, the particle size of the AlCoCrFeNi high-entropy alloy powder is 15-53 μm, and the molar ratio of Al:Co:Cr:Fe:Ni is 1:1:1:1:1.

[0011] Preferably, the amount of the AlCoCrFeNi high-entropy alloy powder is 10% of the mass of the aluminum alloy powder.

[0012] Preferably, the aluminum alloy powder is 7050 aluminum alloy powder with a particle size of 10-30 μm.

[0013] Preferably, in step S3, the temperature for drying the ball-milled powder is 55 DEG C, and the drying time is more than 8 hours.

[0014] Preferably, in step S3, in the last step of the sintering temperature rising process, the temperature is raised to 600 DEG C within 90 minutes, and kept for half an hour.

[0015] Preferably, in step S4, the corrosion resistance and compressive strength of the aluminum matrix composite material can be adjusted by changing the total deformation amount. Compared with the prior art, the present application has the advantages of: (1) The preparation method of the present application realizes the synergistic improvement of the strength, hardness and corrosion resistance of the aluminum matrix composite material. Through large deformation amount (80%) hot rolling, strong work hardening, grain refinement and dynamic recrystallization are induced, so that the hardness reaches 270HV, which is 1.8 times higher than that in the undeformed state; the yield strength reaches 424 MPa, which is 3.5 times higher than that in the undeformed state; through medium deformation amount (40%) hot rolling, the grains are effectively refined, the structure is homogenized, and the diffusion of passivation elements is promoted, so that the corrosion current density is reduced to 3.3344*10 -7 A·cm -2The corrosion potential is improved to-0.63881V (the undeformed state is-0.85727V), and the corrosion resistance is fundamentally improved; the aluminum-based composite material is used for preparing a riser, and meets the service requirement in an extreme environment such as a deep-sea drilling riser.

[0016] (2) The preparation method can regulate the corrosion resistance and compression strength of the aluminum-based composite material by changing the total deformation, that is, the comprehensive performance of the composite material can be targetedly regulated, the requirement of different application scenes (strength, corrosion resistance or comprehensive performance) is met, the process is simple, and the controllability is high.

[0017] Other advantages, objects and features of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a preparation method flowchart of the aluminum-based composite material for the deep-sea drilling riser.

[0019] Figure 2 It is a hardness test result of the final product aluminum-based composite material prepared under the condition of different AlCoCrFeNi high-entropy alloy powder dosages and different sintering temperatures.

[0020] Figure 3 It is a metallographic structure diagram of the final product aluminum-based composite material prepared under the condition of different AlCoCrFeNi high-entropy alloy dosages when the sintering temperature is 600 DEG C.

[0021] Figure 4 It is an SEM diagram of the final product aluminum-based composite material prepared under the condition of different AlCoCrFeNi high-entropy alloy dosages when the sintering temperature is 600 DEG C.

[0022] Figure 5 It is a stress-strain diagram of the final product aluminum-based composite material prepared under the condition of different AlCoCrFeNi high-entropy alloy dosages when the sintering temperature is 600 DEG C.

[0023] Figure 6 It is a metallographic structure diagram of the final product aluminum-based composite material prepared under the condition of different sintering temperatures (550 DEG C, 600 DEG C, 650 DEG C) when the AlCoCrFeNi high-entropy alloy powder dosage is 10%.

[0024] Figure 7 It is a polarization curve of the final product aluminum-based composite material prepared under the condition of different sintering temperatures (550 DEG C, 600 DEG C, 650 DEG C) when the AlCoCrFeNi high-entropy alloy powder dosage is 10%.

[0025] Figure 8is the EDS element distribution map of the aluminum matrix composite prepared under the condition of sintering temperature 600℃ and AlCoCrFeNi high-entropy alloy dosage 10%.

[0026] Figure 9 is the metallographic structure map of the final product aluminum matrix composite prepared under the condition of AlCoCrFeNi high-entropy alloy powder dosage 10% and different sintering modes.

[0027] Figure 10 is the hardness comparison map of the final product aluminum matrix composite prepared under the condition of AlCoCrFeNi high-entropy alloy powder dosage 10% and different sintering modes.

[0028] Figure 11 is the polarization curve of the final product aluminum matrix composite prepared under the condition of AlCoCrFeNi high-entropy alloy powder dosage 10% and different sintering modes.

[0029] Figure 12 is the microstructure map of the aluminum matrix composite prepared in Example 2 and Comparative Example 1.

[0030] Figure 13 is the SEM map of the aluminum matrix composite prepared in Example 2 and Comparative Example 1.

[0031] Figure 14 is the average hardness value of the aluminum matrix composite prepared in Example 2 and Comparative Example 1.

[0032] Figure 15 is the polarization curve of the aluminum matrix composite prepared in Example 2 and Comparative Example 1.

[0033] Figure 16 is the microstructure map of the aluminum matrix composite with different total deformations.

[0034] Figure 17 is the EDS element distribution map of the aluminum matrix composite with total deformation 0%.

[0035] Figure 18 is the EDS element distribution map of the aluminum matrix composite with total deformation 40%.

[0036] Figure 19 is the EDS element distribution map of the aluminum matrix composite with total deformation 80%.

[0037] Figure 20 is the SEM map of the aluminum matrix composite with different total deformations.

[0038] Figure 21 is the average hardness value comparison map of the aluminum matrix composite with different total deformations.

[0039] Figure 22These are stress-strain diagrams of aluminum matrix composites with different total deformation.

[0040] Figure 23 This is a polarization curve of aluminum-based composite materials with different total deformation. Detailed Implementation

[0041] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0042] Example 1 like Figure 1 As shown, the preparation method of the aluminum-based composite material for deep-sea drilling risers of the present invention includes the following specific steps: S1. Using 7050 aluminum alloy powder as the matrix, add the 7050 aluminum alloy powder and AlCoCrFeNi high-entropy alloy powder into a mill and mill at 260 r / min for 3 hours. Change the direction of the mill after 1.5 hours to ensure uniform mixing, thus obtaining a mixed powder of 7050 aluminum alloy and AlCoCrFeNi high-entropy alloy. The 7050 aluminum alloy powder is a mixture of powders with a particle size of 10 μm and 30 μm at a mass ratio of 2:1. The AlCoCrFeNi high-entropy alloy powder has a particle size of 15-53 μm. In this step, the amount of AlCoCrFeNi high-entropy alloy powder is adjusted to 0%, 5%, 10%, and 15% of the mass of the aluminum alloy powder, respectively.

[0043] S2. Place the mixed powder into a planetary ball mill for ball milling. During this process, anhydrous ethanol is added as a process control agent. Add grinding balls (stainless steel balls) with diameters of 4 mm and 6 mm, and control the rotation speed at 320 r / min for 24 hours to make the powder fine and uniform and mechanically alloyed. Specifically, 1000 g of grinding balls are added to every 100 g of mixed powder, with a ball-to-powder ratio of 10:1, and 125 ml of anhydrous ethanol is added.

[0044] S3. Place the ball-milled powder into a drying oven, set the temperature to 55℃, and dry for at least 8 hours to remove process control agents from the mixed powder. Then, place the dried powder into a graphite mold for cold pressing (green compact), with a cold pressing pressure of 100 MPa and a holding time of 60 seconds to obtain a green compact; then, place the green compact along with the mold into a vacuum sintering furnace for vacuum sintering, with a vacuum degree of not less than 1×10⁻⁶. -3Pa, the sintering mode of segmented heating is adopted, and the specific heating process is as follows: heating to 250℃ within 150 minutes, keeping at 250℃ for 1 hour; then heating to 350℃ within 90 minutes, keeping at 350℃ for 1 hour; then heating to 450℃ within 90 minutes, keeping at 450℃ for 1 hour; finally, heating to 550℃ (or 600℃, 650℃) within 90 minutes, keeping at 550℃ (or 600℃, 650℃) for half an hour, and cooling in a vacuum environment to obtain an aluminum matrix composite initial product.

[0045] S4, the rolling roller is preheated to 280℃, then the aluminum matrix composite initial product is heated to 450℃ and kept for 2 hours, and then multi-pass rolling is carried out, and the total deformation amount is controlled to be 60%, and the single-pass deformation amount is not more than 10%, to obtain the final product aluminum matrix composite.

[0046] Different AlCoCrFeNi high-entropy alloy powder amounts and different sintering temperatures in the above method are used to prepare different final product aluminum matrix composites. The hardness test results of different final product aluminum matrix composites are shown in Figure 2 It can be seen that adding different amounts of AlCoCrFeNi powder has a significant effect on the hardness of the composite, and different sintering temperatures also affect the composite, and the aluminum matrix composite prepared under the condition of 10% high-entropy alloy addition and 600℃ sintering has the highest hardness.

[0047] Figure 3 is the metallographic structure diagram of the final product aluminum matrix composite prepared under the condition of different AlCoCrFeNi high-entropy alloy addition amounts when the sintering temperature is 600℃. In the figure, a and b represent 5%; c and d represent 10%; e and f represent 15%. It can be seen that when the AlCoCrFeNi high-entropy alloy particle addition amount is 10%, the high-entropy alloy particles in the prepared aluminum matrix composite are uniformly distributed, and compared with other addition amounts, the particle and aluminum matrix interface fusion is uniform.

[0048] Figure 4 is the SEM diagram of the final product aluminum matrix composite prepared under the condition of different AlCoCrFeNi high-entropy alloy addition amounts when the sintering temperature is 600℃. In the figure, a represents 5%; b represents 10%; c represents 15%. It can be seen that when the addition amount is 5%, fine particles begin to disperse in the matrix to form a preliminary reinforcing phase, but the distribution is still sparse; when the addition amount is 10%, the particle number and density are obviously improved, forming a continuous network structure, which may enhance the load transfer efficiency; when the addition amount is 15%, the particle agglomeration phenomenon is serious, and the quality of the composite material deteriorates.

[0049] Figure 5is the stress-strain diagram of the final product aluminum matrix composite prepared at a sintering temperature of 600℃ and different AlCoCrFeNi high-entropy alloy additive amounts. It can be seen that, with the increase of the additive amount of AlCoCrFeNi high-entropy alloy powder, the strength of the high-entropy alloy particle reinforced aluminum matrix composite is continuously improved. When the additive amount of high-entropy alloy particles is 10%, the compressive strength reaches the maximum value, close to 185 MPa. When the additive amount of high-entropy alloy particles continues to increase to 15%, the strength decreases. Therefore, the preferred additive amount of AlCoCrFeNi high-entropy alloy is 10%.

[0050] Figure 6 is the metallographic structure diagram of the final product aluminum matrix composite prepared at different sintering temperatures (550℃, 600℃, 650℃) and an AlCoCrFeNi high-entropy alloy powder amount of 10%. In the figure, a and b represent 550℃; c and d represent 600℃; e and f represent 650℃. It can be seen that, when the sintering temperature is 600℃, the metallographic structure of the alloy is obvious and the grain boundary is clear, indicating that the sintering quality is the best and good interface bonding is achieved, while too high or too low temperature leads to defects in the structure.

[0051] Figure 7 is the polarization curve of the final product aluminum matrix composite prepared at different sintering temperatures (550℃, 600℃, 650℃) and an AlCoCrFeNi high-entropy alloy powder amount of 10%. It can be seen that different sintering temperatures have an impact on the corrosion resistance of the aluminum matrix composite. From the comprehensive observation of corrosion potential and current density, it is found that the composite material presents the best corrosion resistance at a sintering temperature of 600℃.

[0052] Figure 8 is the EDS element distribution map of the aluminum matrix composite prepared at a sintering temperature of 600℃ and an AlCoCrFeNi high-entropy alloy amount of 10%. By observing the chemical element distribution through EDS, it is found that no O element is detected in the composite material, indicating that the sintering quality of the composite material is good and there is no oxidation phenomenon; the composite material is mainly composed of Mg, Zn, Cu, Al, Co, Fe, Cr, Ni and other elements, the first four elements are mainly the elements of 7050 aluminum alloy, and the last five elements are mainly the elements of AlCoCrFeNi high-entropy alloy particles.

[0053] Figure 9is the metallographic structure diagram of the final product aluminum matrix composite prepared by different sintering methods in step S3 when the AlCoCrFeNi high-entropy alloy powder dosage is 10%. (a) represents the same segmented temperature rising sintering method as example 1, and the final sintering temperature is 600℃. (b) represents direct rapid heating to 600℃ and sintering for half an hour. It can be seen that the temperature rising process of the segmented temperature rising sintering to 600℃ is more gentle, which reduces the risk of uneven heating, ensures the uniformity of the composite material, and the microstructure is more dense, the porosity is reduced, and the diffusion and combination between the powder particles are sufficient. While direct rapid heating to 600℃ sintering can cause local overheating, leading to uneven structure of the composite material, cracks or porosity, and the diffusion and combination between the powder particles may not be sufficient, and the bonding force is weak. The microstructure may not be dense enough, and there are more pores.

[0054] Figure 10 is the hardness comparison diagram of the final product aluminum matrix composite prepared by different sintering methods when the AlCoCrFeNi high-entropy alloy powder dosage is 10%. It can be seen that the hardness of the composite material with segmented temperature rising is obviously higher than that of the composite material with direct temperature rising, because direct temperature rising can cause insufficient combination of powder particles and non-dense structure, and the hardness is relatively low.

[0055] Figure 11 is the polarization curve of the final product aluminum matrix composite prepared by different sintering methods when the AlCoCrFeNi high-entropy alloy powder dosage is 10%. It can be seen that compared with the corrosion resistance of direct temperature rising, the segmented temperature rising sintering has better corrosion resistance from the comprehensive observation of corrosion potential and current density.

[0056] Example 2 According to the preparation method of example 1, the AlCoCrFeNi high-entropy alloy powder dosage is controlled to be 10% in step S1; in step S3, the segmented temperature rising sintering is adopted, and the final sintering temperature is 600℃; in step S4, multi-pass rolling is adopted, and the total deformation amount is controlled to be 80%.

[0057] Comparative example 1 According to the preparation method of example 1, the AlCoCrFeNi high-entropy alloy powder dosage is controlled to be 10% in step S1; in step S3, the segmented temperature rising sintering is adopted, and the final sintering temperature is 600℃; in step S4, one-time rolling is adopted, and the total deformation amount is controlled to be 80%.

[0058] Figure 12are microstructure images of aluminum matrix composites prepared in Example 2 and Comparative Example 1, wherein (a) is the aluminum matrix composite of Example 2, and (b) is the aluminum matrix composite of Comparative Example 1. It can be observed that the multi-pass rolling gradually deforms the grains, which are more uniformly deformed, and helps to form a more regular grain morphology. Gradual compaction makes the composite more dense, and the internal porosity is reduced. The deformation of the one-pass rolling is large and rapid, the grain deformation is uneven, and the grains are broken, resulting in irregular grain morphology. The deformation is too rapid, resulting in pores or loose areas in the composite, and the density is low. Therefore, the aluminum matrix composite obtained by multi-pass rolling is significantly better than that obtained by one-pass rolling.

[0059] Figure 13 are SEM images of aluminum matrix composites prepared in Example 2 and Comparative Example 1, wherein (a) is the aluminum matrix composite of Example 2, and (b) is the aluminum matrix composite of Comparative Example 1. It can be clearly observed that the grains of the one-pass hot rolling composite are significantly deformed, resulting in uneven deformation and local grain breakage. The multi-pass rolling composite can be seen to have high-entropy alloy particles uniformly distributed, with fewer defects. This further demonstrates that the aluminum matrix composite obtained by multi-pass rolling is significantly better than that obtained by one-pass rolling.

[0060] Figure 14 are average hardness values of aluminum matrix composites prepared in Example 2 and Comparative Example 1, wherein (a) is the aluminum matrix composite of Example 2, and (b) is the aluminum matrix composite of Comparative Example 1. It can be seen that the average hardness values under different rolling methods are significantly different. The multi-pass rolling composite has a more uniform grain deformation due to gradual deformation, reduced internal stress, a tighter interface, and improved density, and the hardness is significantly higher than that of the one-pass rolling.

[0061] Figure 15 are polarization curves of aluminum matrix composites prepared in Example 2 and Comparative Example 1, wherein (a) is the aluminum matrix composite of Example 2, and (b) is the aluminum matrix composite of Comparative Example 1. It can be seen that the corrosion resistance of the composite obtained by multi-pass rolling is significantly better than that of the one-pass rolling composite.

[0062] According to the preparation method of Example 2, the total deformation of the multi-pass rolling in step S4 is controlled to be 0%, 20%, 40%, and 60%, respectively, to obtain different aluminum matrix composites. Figure 16are microstructure images of aluminum matrix composites with different total deformations, wherein (a) is a total deformation of 0%, (b) is a total deformation of 20%, (c) is a total deformation of 40%; (d) is a total deformation of 60%; (e) is a total deformation of 80%. It can be seen that under low deformation (20%, 40%), moderate thermal deformation can improve the uniformity of the distribution of the reinforcing phase HEA, the hot rolling pressure promotes the interface bonding between the matrix and the reinforcing phase, the organization interface pores and defects are reduced, and the high-entropy alloy particles undergo obvious plastic deformation. Under high deformation (60%, 80%), the grains in the structure are further refined, and the metal structure under 60% and 80% obviously presents a flat layered distribution along the rolling direction, forming a fiber structure. Under a deformation of 60%, the uniformity index of the distribution of the reinforcing phase is improved, the high-entropy alloy particles undergo plastic deformation, and the matrix material undergoes dynamic recrystallization; under a deformation of 80%, the fiber structure still exists, and the subgrain boundaries evolve into high-angle grain boundaries.

[0063] Figure 17 、 18 , 19 are EDS element distribution maps of aluminum matrix composites with total deformations of 0%, 40%, and 80%, respectively. It can be seen that when the deformation is 40%, the originally aggregated reinforcing phase elements are dispersed, the enrichment area is obviously reduced, the uniformity of element distribution is improved, the interaction between the reinforcing phase and the matrix is enhanced, and the interface bonding state is optimized. Under a deformation of 80%, the fluctuation range of the concentration of each element is basically similar to that of the undeformed sample, and no significant increase in element diffusion distance or significant change in concentration gradient is observed.

[0064] Figure 20 are SEM images of aluminum matrix composites with different total deformations. Among them, (a) represents a total deformation of 20%, (b) represents a total deformation of 40%; (c) represents a total deformation of 80%. It can be seen that when the total deformation is 40%, the SEM image shows that the grains are obviously elongated along the rolling direction, forming a fibrous structure. At this time, the dislocation density in the aluminum matrix increases significantly, the dislocations interweave to form dislocation cell structures, the AlCoCrFeNi high-entropy alloy particles change to some extent, the particle size decreases, and the particles begin to arrange along the rolling direction. Overall, the interface between the particles and the matrix remains continuous and no large-scale debonding phenomenon occurs.

[0065] Figure 21 is a comparison chart of average hardness values of aluminum matrix composites with different total deformations. It can be seen that the hardness value of the undeformed sample is about 150 HV, which represents the basic hardness level of the aluminum matrix in the original state. After hot rolling deformation, the hardness of the samples with deformations of 20%, 40%, 60%, and 80% is about 161 HV, 174 HV, 245 HV, and 270 HV, respectively, which is higher than that of the undeformed sample.

[0066] Figure 22 are stress-strain diagrams of aluminum matrix composites with different total deformations. It can be concluded that the compression performance of aluminum matrix composites after multi-pass hot rolling deformation is significantly better than that in the undeformed state, and when the deformation is 80%, the yield strength increases to 424 MPa. This shows that hot rolling deformation significantly improves the mechanical properties of aluminum matrix composites.

[0067] Figure 23 are polarization curve diagrams of aluminum matrix composites with different total deformations. It can be seen that different hot rolling total deformations have a significant effect on the corrosion resistance of aluminum matrix composites. In combination with the corrosion potential and the corrosion current density, when the hot rolling total deformation is 40%, the corrosion resistance of the aluminum matrix composite reaches the optimum.

[0068] In summary, the preparation method of the present application can realize the synergistic improvement of the strength, hardness and corrosion resistance of the aluminum matrix composite, and the prepared aluminum matrix composite can be used to prepare a deep-sea drilling riser, which is suitable for use in extreme environments (over 3000 meters deep-sea drilling) such as high pressure, high salt and dynamic load.

[0069] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with a preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the present application, and any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present application are still within the scope of the present application.

Claims

1. A method for preparing an aluminum-based composite material for deep-sea drilling risers, characterized in that, Includes the following steps: S1. Aluminum alloy powder and AlCoCrFeNi high-entropy alloy powder are mixed evenly using a jar mill to obtain a mixed powder; S2. The mixed powder is ball-milled to make the powder fine and uniform and mechanically alloyed; S3. The ball-milled powder is dried, then placed in a graphite mold for cold pressing, followed by vacuum sintering. The sintering temperature rise process is as follows: the temperature is raised to 250℃ within 150 minutes and held at 250℃ for 1 hour; then the temperature is raised to 350℃ within 90 minutes and held for 1 hour; then the temperature is raised to 450℃ within 90 minutes and held for 1 hour; finally, the temperature is raised to 550-650℃ within 90 minutes and held for half an hour, followed by vacuum cooling to obtain the initial product of aluminum-based composite material. S4. Preheat the rolls to 280±10℃, then heat the aluminum-based composite material to 450±10℃ and hold for 1-2 hours, then perform multi-pass rolling, controlling the total deformation to 20-80% and the deformation per pass not exceeding 10%, to obtain aluminum-based composite material for deep-sea drilling risers.

2. The preparation method of the aluminum-based composite material for deep-sea drilling risers as described in claim 1, characterized in that, In step S1, the amount of AlCoCrFeNi high-entropy alloy powder used is 5-15% of the mass of aluminum alloy powder.

3. The preparation method of the aluminum-based composite material for deep-sea drilling risers as described in claim 2, characterized in that, The AlCoCrFeNi high-entropy alloy powder has a particle size of 15-53 μm and an Al:Co:Cr:Fe:Ni molar ratio of 1:1:1:1:

1.

4. The preparation method of the aluminum-based composite material for deep-sea drilling risers as described in claim 3, characterized in that, The amount of AlCoCrFeNi high-entropy alloy powder used is 10% of the mass of aluminum alloy powder.

5. The preparation method of the aluminum-based composite material for deep-sea drilling risers as described in claim 2, characterized in that, The aluminum alloy powder is 7050 aluminum alloy powder with a particle size of 10-30 μm.

6. The preparation method of the aluminum-based composite material for deep-sea drilling risers as described in claim 1, characterized in that, In step S3, the powder after ball milling is dried at a temperature of 55°C for at least 8 hours.

7. The preparation method of the aluminum-based composite material for deep-sea drilling risers as described in claim 1, characterized in that, In step S3, the final step of the sintering heating process, the temperature is raised to 600°C within 90 minutes and held for half an hour.

8. The method for preparing aluminum-based composite material for deep-sea drilling risers as described in claim 1, characterized in that, In step S4, the corrosion resistance and compressive strength of the aluminum-based composite material can be controlled by changing the total deformation.

9. An aluminum-based composite material for deep-sea drilling risers, characterized in that, It is prepared by the preparation method described in claims 1-8.

10. An application of the aluminum-based composite material for deep-sea drilling risers as described in claim 9, characterized in that, The aluminum-based composite material is used to prepare a riser suitable for deep-sea drilling.

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