Ni@ stainless steel fiber / porous aluminum composite material and preparation method thereof

Abstract

The application discloses a Ni@ stainless steel fiber / porous aluminum composite material and a preparation method thereof. The material takes an AlSi12 alloy as a matrix and takes Ni@ stainless steel fibers as a reinforced phase. The in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is obtained by using a seepage and in-situ diffusion method. The porosity is 80% to 84%, the pore diameter is 0.5 mm, the volume fraction of the stainless steel fibers is 8 vol.% to 10 vol.%, the fiber diameter is 20 microns to 60 microns, the fiber length is 1 mm to 3 mm, and the compressive yield strength is 1.69 MPa to 3.66 MPa. The compressive yield strength of the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is increased by 4.78% to 6.81% compared to that of a stainless steel fiber / porous aluminum composite material with the same porosity and pore diameter. The in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material has a good bonding interface and improved interface bonding force by atomic diffusion between nickel atoms on the surface of the stainless steel fibers and aluminum atoms of the porous aluminum matrix, and has high strength and high sound absorption characteristics, and is suitable for fields of vibration and noise reduction.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of Ni@ stainless steel fiber / porous aluminum composite material and its preparation method, belong to porous sound-absorbing composite material field. BACKGROUND

[0002] Noise pollution is listed as one of the four major pollution sources today, and its treatment is the most difficult. In order to reduce the impact of noise pollution on human physical and mental health, sound absorption is one of the effective ways to alleviate noise pollution. According to the mechanism, sound-absorbing materials can be divided into two categories: porous sound-absorbing materials and resonant sound-absorbing materials. The sound-absorbing mechanism of resonant materials is to convert sound energy into mechanical energy through material vibration, and then into heat energy. Resonant materials have high sound absorption coefficient at medium and low frequencies, but their structure is complex and the cost is high, which is not conducive to large-scale production. Porous sound-absorbing materials can effectively absorb and attenuate sound wave energy through their unique physical structure and material properties. When sound waves enter the porous sound-absorbing material, sound energy is mainly absorbed by the porous sound-absorbing material through heat dissipation generated by friction between air molecules and pore walls, as well as heat dissipation and viscous dissipation of air flow between pores in the material.

[0003] The raw materials for porous sound absorption include metals, ceramics and synthetic resins, etc. Common porous metal sound-absorbing materials include porous aluminum, porous nickel, porous magnesium, porous iron and porous titanium, etc. Among them, porous aluminum is widely used in the fields of building, aerospace, automobile, public facilities, etc. due to its high porosity, high specific strength, strong heat exchange and heat dissipation capacity, lightweight characteristics and easy transportation, etc. For example, it is used in car interiors, engine compartments and vehicle body panels to effectively reduce noise generated during vehicle operation; it is also used in parts such as jet engine covers and soundproof covers of mechanical equipment. However, due to its unique porous structure, although porous aluminum has good sound absorption performance, its mechanical properties are relatively low. Therefore, how to ensure high sound absorption performance while having high strength properties is an important problem to be solved.

[0004] To solve the problem of improving the mechanical properties of porous metal sound-absorbing materials, the present application uses Ni@ stainless steel fiber as the reinforcing phase, and uses infiltration method to prepare an infiltration precursor sample, and then performs in-situ diffusion treatment. At high temperature, nickel and aluminum atoms in the AlSi12 alloy matrix undergo atomic diffusion migration, forming an in-situ diffusion interface, achieving the purpose of fully utilizing the high strength characteristics of the reinforcing phase to enhance the interfacial bonding strength of the porous sound-absorbing material, and obtaining a Ni@ stainless steel fiber / porous aluminum composite material with high strength and high sound absorption performance. SUMMARY

[0005] To solve the problems described in the technical background, the application provides an in-situ diffusion enhanced Ni@ stainless steel fiber / porous aluminum composite material, the composite material takes AlSi12 alloy as a matrix, Ni@ stainless steel fiber as a reinforced phase, and an interface diffusion layer of Ni and Al formed by using infiltration and in-situ diffusion method to obtain the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material, wherein the thickness of the interface diffusion layer of Ni and Al is 1.25 μm to 3.01 μm, the porosity is 80% to 84%, and the volume fraction of the stainless steel fiber in the Ni@ stainless steel fiber / porous aluminum composite material is 8 vol.% to 10 vol.%.

[0006] According to the application, the compressive yield strength of the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is 1.69 MPa to 3.66 MPa, which is increased by 4.78% to 6.81% compared with the compressive yield strength of the stainless steel fiber / porous aluminum composite material with the same porosity and pore size.

[0007] The thickness of the interface diffusion layer of Ni and Al is 1.25 μm to 3.01 μm, the volume fraction of the stainless steel fiber in the Ni@ stainless steel fiber / porous aluminum composite material is 8 vol.% to 10 vol.%, and the porosity is 80% to 84%.

[0008] The application aims to provide a preparation method of the Ni@ stainless steel fiber / porous aluminum composite material, an atomic diffusion is used to form a composite interface, the interface has good bonding performance, and the overall strength of the material can be effectively improved, the stainless steel fiber is plated with nickel, the nickel-plated stainless steel fiber is mixed with salt, the mixture is pressed into a preform, an aluminum melt is used to infiltrate the preform to obtain a Ni@ stainless steel fiber / aluminum composite material, salt is removed by water washing, and in-situ diffusion is performed to obtain the Ni@ stainless steel fiber / porous aluminum composite material, the diffusion temperature and time are controlled, atomic diffusion occurs at the interface between the stainless steel fiber and the porous aluminum matrix without chemical reaction, formation of an intermediate phase is avoided, an interface diffusion layer of Ni and Al is formed, and the method specifically comprises the following steps.

[0009] (1) Nickel is plated on the surface of the stainless steel fiber to obtain Ni@ stainless steel fiber, the Ni@ stainless steel fiber and NaCl particles are uniformly mixed to obtain a mixture, and then the mixture is pressed into a preform.

[0010] (2) The AlSi12 alloy is heated and melted, and then the aluminum alloy melt is pressed into the pores of the preform by using an infiltration method to prepare a Ni@ stainless steel fiber / aluminum composite material containing NaCl.

[0011] (3) The Ni@ stainless steel fiber / aluminum composite material containing NaCl is used to remove NaCl by water to obtain the Ni@ stainless steel fiber / porous aluminum composite material.

[0012] (4) heating the Ni@ stainless steel fiber / porous aluminum composite material, in-situ diffusion, and after air cooling, obtaining the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material.

[0013] Preferably, the NaCl particles in step (1) of the present application are 0.5mm-0.8mm, the stainless steel fiber diameter is 20μm-60μm, and the length is 1mm-3mm.

[0014] Preferably, the mass percentage of the Ni@ stainless steel fiber in the mixture of step (1) of the present application is 2%-3%, and the mass percentage of the NaCl particles is 97%-98%.

[0015] Preferably, the pressing pressure for preparing the preform in step (1) of the present application is 24kN-26kN.

[0016] Preferably, the pressure used in the infiltration method in step (2) of the present application is 0.4MPa-0.6MPa.

[0017] Preferably, the in-situ diffusion temperature in step (4) of the present application is 350℃-450℃, and the holding time is 30-75min.

[0018] Preferably, the specific process for plating nickel on the surface of the stainless steel fiber of the present application is as follows:

[0019] (1) after degreasing and peeling of the stainless steel fiber, water washing; etching with 5%-8% NaOH for 30-45min, water washing; sensitizing with SnCl2 with a concentration of 8g / L-12g / L for 3min-5min, water washing; activating with silver amine solution with a concentration of 10g / L-15g / L for 5min-10min, water washing;

[0020] (2) chemical nickel plating of the stainless steel fiber with nickel plating solution at 70-85℃, PH value 4.5-5.5 for 40min-60min; the composition of the nickel plating solution includes: nickel sulfate 20g / L-30g / L, potassium borohydride 20g / L-25g / L, boric acid 20g / L-30g / L, thiourea 1mg / L-2mg / L, and additives.

[0021] (3) water washing, and drying.

[0022] The AlSi12 alloy melt is pressed into the pores of the infiltration preform, and the Ni@ stainless steel fiber is compounded with the AlSi12 alloy to form an in-situ diffusion reinforced Ni@ stainless steel fiber / porous aluminum composite. On the one hand, the Ni@ stainless steel fiber exists in the form of hole wall fiber, interstitial fiber and perforation in the AlSi12 porous material. When subjected to stress, the stainless steel fiber in the matrix will produce deflection and displacement, thereby consuming part of the compression energy, transmitting and dispersing stress, and reducing local stress concentration. At the same time, the stainless steel fiber can also pin the crack, inhibit the crack propagation, hinder the compression strain and change the compression collapse path, thereby improving the ability of the porous material to resist external force deformation, and further improving the compression yield strength of the in-situ diffusion reinforced Ni@ stainless steel fiber / porous aluminum composite. On the other hand, the nickel atoms and the aluminum atoms in the AlSi12 will undergo atomic diffusion at high temperature to form a stable interface. The interface tightly connects the stainless steel fiber and the matrix, effectively transmits the stress between the fiber and the matrix, reduces the stress concentration at the interface, and enhances the overall strength, stiffness and impact resistance of the material. At the same time, this also improves the durability and stability of the composite material. Therefore, the interface formed by the atomic diffusion mechanism plays a key interface reinforcing role in the in-situ diffusion reinforced Ni@ stainless steel fiber / porous aluminum composite.

[0023] Invention principle

[0024] (1) In-situ composite interface diffusion layer thickness control principle:

[0025] In-situ diffusion refers to the phenomenon that atoms spontaneously migrate from a high concentration region to a low concentration region in a solid material due to temperature, concentration gradient or other external force field, which can be explained by Fick's law. Therefore, under high temperature conditions, aluminum atoms in the AlSi12 matrix and nickel atoms on the nickel-plated stainless steel fiber will undergo in-situ diffusion migration, forming a stable and uniform ideal interface between the stainless steel fiber and the aluminum alloy matrix. Therefore, by using in-situ diffusion compounding to control the thickness of the in-situ composite interface diffusion layer, the formation of brittle phases is prevented, and an ideal interface that only undergoes atomic diffusion is obtained.

[0026] For the case of planar diffusion, the diffusion thickness model formula is:

[0027]

[0028] where D0 is the diffusion coefficient (unit: m 2 / s), Q is the activation energy (unit: KJ / mol), R is the gas constant (J / (mol·K)), and T is the absolute temperature (unit: K).

[0029] Due to the small atomic radius of aluminum, low melting point and the vacancy diffusion mechanism followed in the displacement solid solution, the diffusion rate of aluminum in nickel is much greater than that of nickel in aluminum. Therefore, it can be approximately regarded as the diffusion of aluminum in nickel, and D0≈1.2*8 -4 m 2 / s, Q≈131KJ / mol, R≈8.314J / (mol*K), and by substituting the temperatures of 350℃ and 450℃ into the above formula, the diffusion layer thickness under different conditions can be obtained.

[0030] (2) In-situ diffusion composite enhancement principle:

[0031] In the in-situ diffusion composite process, the ideal interface between the Ni@ stainless steel fiber and the aluminum matrix should only undergo in-situ diffusion to form a uniform diffusion layer, and the interface is clean and no other brittle phase is generated. The thickness, uniformity and purity of the atomic diffusion layer determine the strength of the metallurgical bonding interface. When the diffusion temperature and time exceed 640℃ and 75min, brittle intermetallic compounds will be formed between nickel and the AlSi12 alloy matrix, which will cause the formation and expansion of microcracks in the material, thereby weakening the interface bonding strength. Therefore, by using the in-situ diffusion composite method, the time and temperature of in-situ diffusion are controlled to prevent the formation of brittle phases.

[0032] By combining the Gibson-Ashby model with experimental data, the relationship between the porosity and the compressive yield strength of the Ni@ stainless steel fiber / porous aluminum composite material can be obtained:

[0033] σ c =1.087(1-ρ) -0.899

[0034] Wherein, σ c : the compressive yield strength (MPa) of the Ni@ stainless steel fiber / porous aluminum composite material, and ρ: the porosity of the Ni@ stainless steel fiber / porous aluminum composite material.

[0035] And the relationship between the compressive yield strength and the porosity of the stainless steel fiber / porous aluminum composite material with the same pore size (0.5mm) is:

[0036]

[0037] Wherein, the compressive yield strength (MPa) of the stainless steel fiber / porous aluminum composite material, and ρ0: the porosity of the stainless steel fiber / porous aluminum composite material.

[0038] Advantages of the present application

[0039] The in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material obtained by the seepage method has a compression yield strength of 1.69-3.66 MPa, which is increased by 4.78%-6.81% compared with the compression yield strength of the stainless steel fiber / porous aluminum composite material with the same porosity and pore size. The atomic diffusion between the nickel atoms on the surface of the stainless steel fiber and the aluminum atoms in the porous aluminum matrix generates a composite interface and improves the interface bonding force. The Ni@ stainless steel fiber / porous aluminum composite material has high strength and high sound absorption characteristics, and can meet the application requirements in the technical field of sound absorption and noise reduction. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 Process flow chart of the Ni@ stainless steel fiber / porous aluminum composite material. DETAILED DESCRIPTION

[0041] Example 1

[0042] In this embodiment, the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is prepared by the following steps.

[0043] (1) The 20 μm diameter and 1 mm length stainless steel fiber is degreased and peeled.

[0044] (2) The stainless steel fiber is cleaned with deionized water, dried in a drying oven, etched with 5% NaOH solution, cleaned with deionized water, and dried to be pretreated.

[0045] (3) The Ni@ stainless steel fiber is obtained by electroless plating nickel at 70°C and PH value of 4.5 for 40 min using a nickel plating solution containing nickel sulfate 30 g / L, potassium borohydride 25 g / L, boric acid 30 g / L, thiourea 2 mg / L, and other additives, and then washed with water and dried.

[0046] (4) The NaCl particles with a particle size of 0.5 mm and the Ni@ stainless steel fiber with a volume fraction of 8-10 vol.% are uniformly mixed, and then pressed at a pressure of 26 MPa for 5 min to obtain a mixed preform of the Ni@ stainless steel fiber and the salt particles.

[0047] (5) The AlSi12 alloy is heated to 650°C to be melted, and then the AlSi12 alloy melt is pressed into the pores of the mixed preform of the Ni@ stainless steel fiber and the salt particles at a pressure of 0.4 MPa to obtain a salt-containing Ni@ stainless steel fiber / aluminum composite material.

[0048] (6) The salt-containing Ni@ stainless steel fiber / aluminum composite material is water-soluble desalted to obtain a Ni@ stainless steel fiber / porous aluminum composite material with a porosity of 84%.

[0049] (7) The Ni@ stainless steel fiber / porous aluminum composite material is in-situ diffusion treated at a temperature of 350°C for 30 min, so that the nickel on the surface of the Ni@ stainless steel fiber and the aluminum matrix are atomically diffused to form a composite interface. After air cooling, an in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material with an interface diffusion layer thickness of 1.25 μm and a compressive yield strength of 1.69 MPa is obtained. The compressive yield strength of the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is increased by 4.78% compared with that of the stainless steel fiber / porous aluminum composite material with the same porosity and pore size.

[0050] Example 2

[0051] In this example, the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is prepared by the following steps.

[0052] (1) The stainless steel fiber with a diameter of 20 μm and a length of 1 mm is degreased and peeled.

[0053] (2) The stainless steel fiber is cleaned with deionized water, dried in a drying oven, etched with 5% NaOH solution, cleaned with deionized water, and dried to be pretreated.

[0054] (3) The stainless steel fiber is chemically plated with nickel at 75°C and a pH value of 4.5 for 45 min by using a nickel plating solution with a composition of nickel sulfate 30 g / L, potassium borohydride 25 g / L, boric acid 30 g / L, thiourea 2 mg / L, and other additives, washed with water, and dried to obtain the Ni@ stainless steel fiber.

[0055] (4) The NaCl particles with a particle size of 0.5 mm and the Ni@ stainless steel fiber with a volume fraction of 8 vol.% to 10 vol.% are uniformly mixed, and a mixed preform of the Ni@ stainless steel fiber and the salt particles is obtained under a pressure of 25.5 MPa for 5 min.

[0056] (5) The AlSi12 alloy is heated to 650°C to be melted, and the AlSi12 alloy melt is pressed into the pores of the mixed preform of the Ni@ stainless steel fiber and the salt particles under a pressure of 0.4 MPa to obtain a salt-containing Ni@ stainless steel fiber / aluminum composite material.

[0057] (6) The salt-containing Ni@ stainless steel fiber / aluminum composite material is water-solubly desalted to obtain a Ni@ stainless steel fiber / porous aluminum composite material with a porosity of 83%.

[0058] (7) The Ni@ stainless steel fiber / porous aluminum composite material is in-situ diffusion treated at a temperature of 350°C for 45 min, so that the nickel on the surface of the Ni@ stainless steel fiber and the aluminum matrix are atomically diffused to form a composite interface. After air cooling, an in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material with an interface diffusion layer thickness of 1.51 μm and a compressive yield strength of 2.13 MPa is obtained. The compressive yield strength of the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is increased by 4.96% compared with that of the stainless steel fiber / porous aluminum composite material with the same porosity and pore size.

[0059] Example 3

[0060] In this example, the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is prepared by the following steps.

[0061] (1) The stainless steel fiber with a diameter of 20 μm and a length of 1 mm is degreased and disbonded.

[0062] (2) The stainless steel fiber is cleaned with deionized water, dried in a drying oven, etched with a 5% NaOH solution, cleaned with deionized water, and dried to be pretreated.

[0063] (3) The stainless steel fiber is chemically plated with nickel at 80°C and a pH value of 4.5 for 50 min by using a nickel plating solution with a composition of nickel sulfate 30 g / L, potassium borohydride 25 g / L, boric acid 30 g / L, thiourea 2 mg / L, and other additives, washed with water, and dried to obtain the Ni@ stainless steel fiber.

[0064] (4) The NaCl particles with a particle size of 0.5 mm and the Ni@ stainless steel fiber with a volume fraction of 8 vol.% to 10 vol.% are uniformly mixed, and a mixed preform of the Ni@ stainless steel fiber and the salt particles is obtained by pressing at a pressure of 25 MPa for 5 min.

[0065] (5) The AlSi12 alloy is heated to 650°C to be melted, and the molten AlSi12 alloy is pressed into the pores of the mixed preform of the Ni@ stainless steel fiber and the salt particles at a pressure of 0.4 MPa to obtain a salt-containing Ni@ stainless steel fiber / aluminum composite material.

[0066] (6) The salt-containing Ni@ stainless steel fiber / aluminum composite material is water-solubly desalted to obtain a Ni@ stainless steel fiber / porous aluminum composite material with a porosity of 82%.

[0067] (7) The Ni@ stainless steel fiber / porous aluminum composite material is in-situ diffusion treated at a temperature of 450°C for 60 min, so that the nickel on the surface of the Ni@ stainless steel fiber and the aluminum matrix are atomically diffused to form a composite interface. After air cooling, an in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material with an interface diffusion layer thickness of 2.52 μm and a compressive yield strength of 2.38 MPa is obtained. The compressive yield strength of the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is increased by 6.63% compared with that of the stainless steel fiber / porous aluminum composite material with the same porosity and pore size.

[0068] Example 4

[0069] In this example, the in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material is prepared by the following steps.

[0070] (1) The stainless steel fiber with a diameter of 20 μm and a length of 1 mm is degreased and debonded.

[0071] (2) The stainless steel fiber is cleaned with deionized water, dried in a drying oven, etched with 5% NaOH solution, cleaned with deionized water, and dried to be pretreated.

[0072] (3) The stainless steel fiber is chemically plated with nickel at 85°C and a pH value of 4.5 for 60 min by using a nickel plating solution with a composition of nickel sulfate 30 g / L, potassium borohydride 25 g / L, boric acid 30 g / L, thiourea 2 mg / L, and other additives, washed with water, and dried to obtain the Ni@ stainless steel fiber.

[0073] (4) The NaCl particles with a particle size of 0.5 mm and the Ni@ stainless steel fiber with a volume fraction of 8 vol.% to 10 vol.% are uniformly mixed, and a mixed preform of the Ni@ stainless steel fiber and the salt particles is obtained by pressing at a pressure of 24 MPa for 5 min.

[0074] (5) The AlSi12 alloy is heated to 650°C to be melted, and the molten AlSi12 alloy is pressed into the pores of the mixed preform of the Ni@ stainless steel fiber and the salt particles at a pressure of 0.4 MPa to obtain a salt-containing Ni@ stainless steel fiber / aluminum composite material.

[0075] (6) The salt-containing Ni@ stainless steel fiber / aluminum composite material is water-solubly desalted to obtain a Ni@ stainless steel fiber / porous aluminum composite material with a porosity of 80%.

[0076] (7) The Ni@ stainless steel fiber / porous aluminum composite material is subjected to in-situ diffusion treatment at a temperature of 450 ℃ for 75 min, so that the nickel on the surface of the Ni@ stainless steel fiber and the aluminum matrix are atomically diffused to form a good bonding interface. After air cooling, an in-situ diffusion composite reinforced Ni@ stainless steel fiber / porous aluminum composite material with an interface diffusion layer thickness of 3.01 μm and a compressive yield strength of 3.66 MPa is obtained, which is improved by 6.81% compared with the compressive yield strength of the stainless steel fiber / porous aluminum composite material with the same porosity and pore size.

Claims

1. A Ni@stainless steel fiber / porous aluminum composite material, characterized in that: The composite material uses AlSi12 alloy as the matrix and Ni@stainless steel fiber as the reinforcing phase. A Ni-Al interfacial diffusion layer is formed by infiltration and in-situ diffusion methods to obtain an in-situ diffused composite reinforced Ni@stainless steel fiber / porous aluminum composite material. The thickness of the Ni-Al interfacial diffusion layer is 1.25 μm to 3.01 μm, the porosity is 80% to 84%, and the volume fraction of stainless steel fiber in the Ni@stainless steel fiber / porous aluminum composite material is 8 vol.% to 10 vol.%.

2. The method for preparing Ni@stainless steel fiber / porous aluminum composite material according to claim 1, characterized in that: The process involves nickel plating of stainless steel fibers, mixing the nickel-plated stainless steel fibers with salt, pressing them into a preform, and then percolating the preform with molten aluminum to obtain a Ni@stainless steel fiber / aluminum composite material. After washing to remove the salt, in-situ diffusion is performed to obtain a Ni@stainless steel fiber / porous aluminum composite material. By controlling the diffusion temperature and time, only atomic diffusion occurs at the interface between the stainless steel fibers and the porous aluminum matrix without chemical reaction, thus avoiding the formation of intermediate phases. The resulting Ni / Al interface diffusion layer yields an in-situ diffused composite reinforced Ni@stainless steel fiber / porous aluminum composite material.

3. The method for preparing the Ni@stainless steel fiber / porous aluminum composite material according to claim 2, characterized in that, Specifically, the following steps are included: (1) Nickel is plated on the surface of stainless steel fibers to obtain Ni@ stainless steel fibers. The Ni@ stainless steel fibers and NaCl particles are mixed to obtain a mixture, and then pressed into a preform. (2) After heating and melting AlSi12 alloy, the aluminum alloy melt is pressed into the pores of the preform by percolation method to prepare Ni@stainless steel fiber / aluminum composite material containing NaCl. (3) The NaCl-containing Ni@stainless steel fiber / aluminum composite material was obtained by dissolving NaCl in water to obtain Ni@stainless steel fiber / porous aluminum composite material. (4) The Ni@stainless steel fiber / porous aluminum composite material was heated and diffused in situ, and then air-cooled to obtain the in situ diffused composite reinforced Ni@stainless steel fiber / porous aluminum composite material.

4. The method for preparing the Ni@stainless steel fiber / porous aluminum composite material according to claim 3, characterized in that: In step (1), the NaCl particles are 0.5 mm to 0.8 mm in diameter, and the stainless steel fibers are 20 μm to 60 μm in diameter and 1 mm to 3 mm in length.

5. The method for preparing the Ni@stainless steel fiber / porous aluminum composite material according to claim 3, characterized in that: In step (1), the mass percentage of Ni@stainless steel fiber in the mixture is 2% to 3%, and the mass percentage of NaCl particles is 97% to 98%.

6. The method for preparing the Ni@stainless steel fiber / porous aluminum composite material according to claim 3, characterized in that: The pressure applied during the preparation of the preform in step (1) is 24 kN to 26 kN.

7. The method for preparing the Ni@stainless steel fiber / porous aluminum composite material according to claim 3, characterized in that: The pressure used in step (2) for the seepage method is 0.4MPa to 0.6MPa.

8. The method for preparing the Ni@stainless steel fiber / porous aluminum composite material according to claim 3, characterized in that: In step (4), the in-situ diffusion temperature is 350℃~450℃ and the holding time is 30~75min.

9. The method for preparing the Ni@stainless steel fiber / porous aluminum composite material according to claim 3, characterized in that, The specific process of nickel plating on the surface of stainless steel fibers is as follows: (1) After degreasing and degumming the stainless steel fiber, wash it with water; etch it with 5% to 8% NaOH for 30 to 45 min, then wash it with water; sensitize it with SnCl2 at a concentration of 8 g / L to 12 g / L for 3 to 5 min, then wash it with water; activate it with silver ammonia solution at a concentration of 10 g / L to 15 g / L for 5 to 10 min, then wash it with water. (2) Stainless steel fibers are electroplated with nickel in a nickel plating solution at 70-85℃ and pH 4.5-5.5 for 40-60 minutes. The nickel plating solution consists of: nickel sulfate 20g / L-30g / L, potassium borohydride 20g / L-25g / L, boric acid 20g / L-30g / L, thiourea 1mg / L-2mg / L and additives. (3) Wash with water and dry.

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