High-performance Fe-Cu composite material and preparation method thereof

Abstract

The invention discloses a high-performance Fe-Cu composite material and a preparation method thereof.The preparation method comprises the following steps that Fe powder and SiC particles are mixed and then subjected to mechanical ball milling, and SiC / Fe powder is obtained; cu powder and Ni powder are taken, SiC / Fe powder and Cu powder are laid in a mold according to the symmetrical sandwich layered structure, a layer of Ni powder is laid at the interface of SiC / Fe powder and Cu powder to serve as a transition layer, and the needed layered structure material is obtained through SPS sintering; and after a layered structure material is obtained through SPS sintering, hot rolling is conducted, and the high-performance Fe-Cu composite material is obtained. The SiC particles are added into the Fe layer to refine grains of a Fe matrix, the problem that Fe and Cu are difficult to be tightly connected is solved by designing the Ni transition layer, finally, the SiCp / Fe-Ni-Cu dissimilar metal layered structure is prepared by adopting the SPS technology, and the mechanical property and the heat conductivity of the prepared Fe-Cu composite material are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of material processing, and in particular to a high-performance Fe-Cu composite material and a preparation method thereof. Background Art

[0002] With the acceleration of technological iteration, high-tech industries have increasingly stringent requirements for the comprehensive performance of materials. At present, the improvement of material performance by a single structure has reached a bottleneck, which has made researchers realize the importance of developing multi-structure materials (bimodal structure, multimodal structure and layered structure). Iron (Fe), as one of the most common metals in industrial applications, has a wide range of application prospects; while copper (Cu) is favored in many fields due to its excellent thermal conductivity.

[0003] Combining the advantages of Fe and Cu, developing a material combination that can provide excellent thermal properties, strength and plasticity at the same time is crucial to meet the requirements of high thermal conductivity and high strength for key components such as nuclear reactors, heat exchangers and die-casting molds. However, due to the significant differences in atomic diameter and crystal structure between Fe and Cu, it is challenging to directly form a solid solution between the two, which creates a huge obstacle to the formation of a tight interface between Fe and Cu.

[0004] In recent years, researchers have invested a lot of energy in the study of dissimilar metal bonding and found that high temperature and high pressure conditions help promote diffusion and bonding between dissimilar metal interfaces. Therefore, welding, additive manufacturing and powder metallurgy technology have become the main means of preparing Fe-Cu layered structures. However, welding and additive manufacturing are both carried out at temperatures higher than the melting points of Fe and Cu. The different thermal expansion coefficients of the two metals will lead to higher interfacial stress after cooling, which will lead to defects such as cracks and pores. Summary of the invention

[0005] Technical problem to be solved: In view of the problem that it is difficult to form a tight interface bonding between Fe and Cu in the prior art, the present invention proposes a high-performance Fe-Cu composite material and a preparation method thereof, wherein SiC particles are added to the Fe layer to refine the grains of the Fe matrix, and the problem that it is difficult to form a tight connection between Fe and Cu is overcome by designing a Ni transition layer, and finally, a SiCp / Fe-Ni-Cu heterogeneous metal layered structure is prepared by SPS technology and hot-rolled, so that the mechanical properties of the prepared Fe-Cu composite material such as yield strength, tensile strength and elongation are improved, and the thermal conductivity performance is also greatly improved.

[0006] Technical solution: The first object of the present invention is to provide a method for preparing a high-performance Fe-Cu composite material, the steps are as follows:

[0007] Step 1: Mix Fe powder and SiC particles, and then perform mechanical ball milling to obtain SiC / Fe powder;

[0008] Step 2: Take Cu powder and Ni powder, and lay SiC / Fe powder and Cu powder in a mold according to a symmetrical sandwich layered structure, wherein the thickness of SiC / Fe powder and Cu powder is 1.0-1.2 mm, and at the same time lay a layer of Ni powder at the interface of SiC / Fe powder and Cu powder, wherein the thickness of Ni powder is 0.1-0.15 mm, wherein the number of layers of Cu powder is n, the number of layers of SiC / Fe powder is n+1, and the number of layers of Ni powder is 2n, where n is a positive integer, and the desired layered structure material is obtained by SPS sintering;

[0009] Step 3: After SPS sintering to obtain a layered structure material, hot rolling is performed to obtain a high-performance Fe-Cu composite material.

[0010] Preferably, the volume fraction of SiC particles in step 1 is 3%.

[0011] Preferably, the mechanical ball milling time in step 1 is 5-8 hours and the rotation speed is 250 rpm.

[0012] Preferably, in step 1, the diameter of the Fe powder is 5-15 μm, and the diameter of the SiC particles is 3-5 μm.

[0013] Preferably, in step 2, the diameter of the Cu powder is 5-15 μm, and the diameter of the Ni powder is 3-5 μm.

[0014] Preferably, in the step 2, the SPS sintering temperature is 850-950° C., the pressure is 40-50 MPa, and the holding time is 20-30 min.

[0015] Preferably, the hot rolling in step three is specifically as follows: the hot rolling temperature is 900-1000° C., the deformation amount is 50-55%, the rolling amount per pass is 10%, a total of 5-6 passes are performed, and tempering is performed for 2-3 minutes between each pass.

[0016] The second object of the present invention is to provide a high-performance Fe-Cu composite material prepared by the above method.

[0017] Spark plasma sintering technology (SPS) can provide pulse current, temperature and pressure conditions at the same time, and is an ideal way to prepare Fe-Cu composite materials. The present invention introduces nickel (Ni) as a transition layer between Fe and Cu to form a Fe-Ni-Cu symmetrical sandwich layered structure. This design not only helps to alleviate the interface bonding problem caused by the differences in atomic diameter and crystal structure between Fe and Cu, but also improves the plasticity of the composite material, so that it exhibits better mechanical properties under complex stress conditions. And in order to further improve the strength of the material, the present invention adds an appropriate amount of SiC particles to Fe, and uses SPS sintering technology to prepare SiC / Fe-Ni-Cu symmetrical sandwich layered structure composite materials, which greatly improves the mechanical properties and thermal conductivity of the composite material.

[0018] Beneficial effects:

[0019] 1. The present invention refines the grains of the Fe matrix by adding SiC particles to the Fe layer, and prepares the SiCp / Fe-Ni-Cu heterogeneous metal layered structure by using SPS technology. The heterogeneous structure design significantly improves the strength of the layered structure compared to pure Fe. Figure 2 shown.

[0020] 2. The present invention overcomes the problem of the difficulty in closely connecting Fe and Cu by designing a Ni transition layer. The introduction of the Ni transition layer enables metallurgical bonding between the metal layers to be formed with amorphous compounds as the medium, such as Figure 3 As shown. Different from the mechanical bonding formed by direct contact between the Fe layer and the Cu layer, the metallurgical bonding interface plays an important role in bearing and transmitting loads, improving the yield strength, tensile strength and elongation of the material. The plasticity of the SiCp / Fe-Ni-Cu structure is 280% of that of SiCp / Fe-Cu, as shown Figure 2 shown.

[0021] 3. The introduction of the Cu layer in the present invention greatly improves the thermal conductivity of the material as a whole, and obtains a material with excellent mechanical properties and high comprehensive performance of thermal conductivity. The thermal conductivity of the SiCp / Fe-Cu symmetric layered structure is 169.54% of that of pure Fe, and the thermal conductivity of the SiCp / Fe-Ni-Cu symmetric sandwich layered structure is 248.70% of that of pure Fe. Figure 4 shown. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a process roadmap for preparing a high-performance Fe-Cu composite material (SiCp / Fe-Ni-Cu symmetrical sandwich layered structure composite material) of the present invention;

[0023] Figure 2The mechanical properties diagram of the materials prepared in Example 1 and Comparative Examples 1-3, wherein the legend Fe represents Comparative Example 3, Fe-Cu represents Comparative Example 1, Fe-Ni-Cu (not hot-rolled) represents Comparative Example 2, and Fe-Ni-Cu represents Example 1;

[0024] Figure 3 Figures are interface bonding diagrams of SiCp / Fe-Cu prepared in Comparative Example 1 and SiCp / Fe-Ni-Cu prepared in Example 1, wherein a) is a diagram of the interface bonding of SiCp / Fe-Cu, and b) is a diagram of the interface bonding of SiCp / Fe-Ni-Cu;

[0025] Figure 4 The thermal conductivity diagram of three materials prepared in Example 1 and Comparative Examples 1 and 3, wherein Fe represents Comparative Example 3, Fe-Cu represents Comparative Example 1, and Fe-Ni-Cu represents Example 1;

[0026] Figure 5 The SEM image of the interface of the SiCp / Fe-Ni-Cu material prepared in Example 1, in which the scale of a) is 20 μm, the scale of b) is 10 μm, c) is a partial enlarged image of the framed portion in a); d) is a partial enlarged image of the framed portion in b);

[0027] Figure 6 The element distribution at the interface of the SiCp / Fe-Ni-Cu material prepared in Example 1, in which a) is a superimposed distribution diagram of each element, b) is the distribution of Fe element, c) is the distribution of Ni element, d) is the distribution of Cu element, e) is the distribution of O element, and f) is the distribution of Si element;

[0028] Figure 7 EBSD images of the interface of SiCp / Fe-Ni-Cu material prepared in Example 1, in which a) is an IPF image of the interface, and b) is a locally enlarged IPF image of the interface;

[0029] Figure 8 This is a tensile fracture diagram at the interface of the SiCp / Fe-Ni-Cu material prepared in Example 1, in which a) is the material without hot rolling, and b) is the material after hot rolling. DETAILED DESCRIPTION

[0030] The embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings and examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If specific conditions are not specified in the examples, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0031] In terms of the performance test of the embodiments of the present invention and the comparative examples, the hardness values ​​of the layers and the interfaces between the layers of the layered structure were measured using a HV-1000A Vickers hardness tester. The thermal conductivity of the layered structure was measured using a NETZSCH LFA467 laser thermal conductivity test analyzer. The mechanical properties of the material were measured using an INSTRON 8801 hydraulic servo fatigue testing machine, with the measurement temperature being room temperature (22.5°C) and the strain rate being 8.3×10 -4 s -1 .

[0032] In terms of microstructural characterization of the embodiments of the present invention and the comparative examples, the morphology and tensile fracture of each layer of the layered structure were observed using a Gemini SEM 300 field emission scanning electron microscope (SEM). Phases were identified on a TD-3500 X-ray diffractometer (XRD) and the types of interface products were analyzed. Transmission samples were prepared using a Helios focused ion beam (FIB), and the interface structure was observed on a FEI Tecnai F20 transmission electron microscope (TEM). The Oxford-SYMMETRY electron backscatter diffraction pattern acquisition device (EBSD) was used to collect crystallographic information of the composite material, and AZtecCrystal software was used for data post-processing.

[0033] Example 1

[0034] This embodiment provides a method for preparing a SiCp / Fe-Ni-Cu symmetrical sandwich layered structure composite material. Figure 1 , and its preparation method comprises:

[0035] 1. Select Fe powder with a diameter between 5-15μm, select SiC particles with a diameter between 3-5μm, and use mechanical ball milling to obtain a mixed powder of SiC particles and Fe powder with a volume fraction of 3%. The specific process of mechanical ball milling is as follows: put the selected Fe powder and SiC particles into a ball mill, and then add stainless steel balls with a diameter of 10mm and anhydrous ethanol into the ball mill. The weight ratio of stainless steel balls to powder is 5:1, and the amount of anhydrous ethanol is 10ml per gram of powder. Place the ball mill in a ball mill (such as Figure 1 The samples were ball milled at 250 rpm for 6 h.

[0036] 2. Take Cu powder and Ni powder, the diameter of Cu powder is 5-15μm, the diameter of Ni powder is 3-5μm, and 3% SiC / Fe powder and Cu powder are laid in a graphite mold according to a symmetrical structure. The thickness of SiC / Fe powder and Cu powder is 1.0mm, and a layer of Ni powder (powder thickness 0.12mm) is laid at the interface of 3% SiC / Fe powder and Cu powder as a transition layer. In this embodiment, the total number of layers is 9 (3% SiC / Fe powder three layers, Cu powder two layers, Ni powder four layers), and the structural schematic diagram is as follows: Figure 1 The desired layered structure material is obtained by SPS sintering, the sintering temperature is 900℃, the pressure is 40MPa, and the holding time is 20min.

[0037] 3. After SPS sintering to obtain the layered structure material, hot rolling with a deformation of 50% is carried out at 950°C. The rolling amount of each pass is 10%, and a total of 5 passes are carried out. Tempering for 2 minutes between each pass. The process is as follows Figure 1 shown.

[0038] Example 2

[0039] This embodiment provides a method for preparing a SiCp / Fe-Ni-Cu symmetrical sandwich layered structure composite material, the preparation method comprising:

[0040] 1. Select Fe powder with a diameter between 5-15μm and SiC particles with a diameter between 3-5μm, and use mechanical ball milling to obtain a mixed powder of SiC particles and Fe powder with a volume fraction of 3%. The specific process of mechanical ball milling is as follows: put the selected Fe powder and SiC particles into a ball mill, and then add stainless steel balls with a diameter of 10mm and anhydrous ethanol to the ball mill. The weight ratio of stainless steel balls to powder is 5:1, and the amount of anhydrous ethanol is 10ml per gram of powder. Put the ball mill on a ball mill and mill at a speed of 250 rpm for 5 hours.

[0041] 2. Take Cu powder and Ni powder, the diameter of Cu powder is 5-15μm, the diameter of Ni powder is 3-5μm, and lay 3% SiC / Fe powder and Cu powder in a graphite mold according to a symmetrical structure. The thickness of SiC / Fe powder and Cu powder is 1.0mm, and a layer of Ni powder (powder thickness 0.1mm) is laid at the interface of 3% SiC / Fe powder and Cu powder as a transition layer. In this embodiment, the total number of layers is 9 (3% SiC / Fe powder three layers, Cu powder two layers, Ni powder four layers). The desired layered structure material is obtained by SPS sintering, the sintering temperature is 850℃, the pressure is 40MPa, and the holding time is 20min.

[0042] 3. After the layered structure material is obtained by SPS sintering, hot rolling with a deformation of 50% is carried out at 900°C, and the rolling amount of each pass is 10%. There are 5 passes in total, and tempering is performed for 2 minutes between each pass.

[0043] Example 3

[0044] This embodiment provides a method for preparing a SiCp / Fe-Ni-Cu symmetrical sandwich layered structure composite material, the preparation method comprising:

[0045] 1. Select Fe powder with a diameter between 5-15μm and SiC particles with a diameter between 3-5μm, and use mechanical ball milling to obtain a mixed powder of SiC particles and Fe powder with a volume fraction of 3%. The specific process of mechanical ball milling: put the selected Fe powder and SiC particles into a ball mill, and then add stainless steel balls with a diameter of 10mm and anhydrous ethanol to the ball mill. The weight ratio of stainless steel balls to powder is 5:1, and the amount of anhydrous ethanol is 10ml per gram of powder. Put the ball mill on a ball mill and mill at a speed of 250 rpm for 8 hours.

[0046] 2. Take Cu powder and Ni powder, the diameter of Cu powder is 5-15μm, the diameter of Ni powder is 3-5μm, and lay 3% SiC / Fe powder and Cu powder in a graphite mold according to a symmetrical structure. The thickness of SiC / Fe powder and Cu powder is 1.2mm, and a layer of Ni powder (powder thickness 0.15mm) is laid at the interface of 3% SiC / Fe powder and Cu powder as a transition layer. In this embodiment, the total number of layers is 9 (3% SiC / Fe powder three layers, Cu powder two layers, Ni powder four layers). The desired layered structure material is obtained by SPS sintering, the sintering temperature is 950℃, the pressure is 50MPa, and the holding time is 30min.

[0047] 3. After the layered structure material is obtained by SPS sintering, hot rolling with a deformation of 55% is carried out at 1000°C, and the rolling amount of each pass is 10%. A total of 5 passes are carried out, and tempering is performed for 2 minutes between each pass.

[0048] Comparative Example 1

[0049] Same as Example 1, except that:

[0050] As a control group, only 3% SiCp / Fe powder and Cu powder were laid alternately in the graphite mold without laying a Ni transition layer. Figure 1 shown.

[0051] Comparative Example 2

[0052] Same as Example 1, except that:

[0053] As a control group, the SPS sintered samples were directly tested as final samples without hot rolling process.

[0054] Comparative Example 3

[0055] Same as Example 1, except that:

[0056] As a control group, Fe powder was no longer mixed with Cu powder and Ni powder, and the Fe powder was directly subjected to SPS sintering and subsequent hot rolling.

[0057] The layered composite materials prepared in Example 1 and Comparative Examples 1-3 were subjected to performance testing and microscopic characterization.

[0058] Figure 5 This is a SEM image of the interface of the SiCp / Fe-Ni-Cu material prepared in Example 1. It can be seen from the figure that the interlayer interface of the SiCp / Fe-Ni-Cu symmetrical sandwich structure with the Ni modified layer is relatively smooth, indicating that the Ni modified layer plays a good role in transition and promoting interface bonding. The enlarged view of the interlayer interface shows that the Ni transition layer is well bonded to the 3% SiCp / Fe layer, and there is no obvious boundary line or crack on the interface.

[0059] Figure 6 This is an element distribution diagram of the SiCp / Fe-Ni-Cu symmetrical sandwich structure prepared in Example 1. It can be seen from the figure that Fe, Ni and a small amount of O are enriched at the interlayer interface, indicating that the hot rolling process promotes the diffusion of elements at the interlayer interface.

[0060] like Figure 2 and Figure 4 As shown, the SiC / Fe-Cu composite material without the addition of the Ni transition layer is inferior to the SiC / Fe-Cu composite material with the addition of the Ni transition layer in terms of mechanical properties and thermal conductivity. The introduction of the Cu layer greatly improves the thermal conductivity of the material as a whole, and obtains a material with high comprehensive performance of excellent mechanical properties and thermal conductivity. The thermal conductivity data of the three materials Fe (Comparative Example 3), SiCp / Fe-Cu (Comparative Example 1), and SiCp / Fe-Ni-Cu (Example 1) are shown in Table 1. Thanks to the promotion of the interface bonding by the Ni modification layer, a more efficient channel is provided for heat flow transfer. The SiCp / Fe-Cu layered structure is 169.54% of the thermal conductivity of pure Fe, and the SiCp / Fe-Ni-Cu symmetrical sandwich layered structure is 248.70% of pure Fe.

[0061] Table 1 Thermal conductivity data of three materials: Fe, SiCp / Fe-Cu, SiCp / Fe-Ni-Cu

[0062] Material Fe SiCp / Fe-Cu SiCp / Fe-Ni-Cu Thermal conductivity (W / (mk)) 80 135.63 198.96 Thermal conductivity compared to Fe 100％ 169.54％ 248.70％

[0063] Figure 7 The EBSD map and local magnification of the interlayer interface of the SiCp / Fe-Ni-Cu symmetrical sandwich layered structure are shown. A fine-grained layer was observed at the interlayer interface where the Ni transition layer was added. The hot rolling process stimulated the nucleation of SiC particles and inhibited the growth of grains, resulting in a significant reduction in the grain size of the 3% SiCp / Fe layer after hot rolling. The fine grain strengthening effect significantly improved the material strength, such as Figure 2The introduction of the Ni transition layer enables the metal layers to form a metallurgical bond mediated by amorphous compounds, such as Figure 3 shown.

[0064] The tensile fracture morphology of SiCp / Fe-Ni-Cu symmetrical sandwich structure is as follows Figure 8 As shown in the figure, the different plastic deformation capabilities of each layer of the unhot-rolled SiCp / Fe-Ni-Cu symmetrical sandwich layered structure material lead to different fracture directions at the interface. The fracture of the Cu layer is distributed at 45° along the tensile direction, as shown by the arrow in the figure. The Ni layer of the hot-rolled material has achieved good bonding with the Cu layer and the Fe layer, playing a significant transition and connection role. This makes the fracture directions of the Cu layer and the Fe layer at the interface consistent, as shown by the arrow in the figure. Since the interlayer interface bonding of the layered structure with the addition of the Ni modified layer is more firmly bonded, it plays a better role in coordinating deformation during the plastic deformation process, which is also the main reason why the hot-rolled SiCp / Fe-Ni-Cu symmetrical sandwich layered structure has higher strength and plasticity.

[0065] Finally, it should be noted that the above implementation modes are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned implementation modes, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned implementation modes can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the implementation modes of the present invention.

Claims

1. A method for preparing a high-performance Fe-Cu composite material, characterized in that: Here are the steps: Step 1: Mix Fe powder and SiC particles, and then perform mechanical ball milling to obtain SiC / Fe powder; Step 2: Take Cu powder and Ni powder, and lay SiC / Fe powder and Cu powder in a mold in sequence according to a symmetrical sandwich layered structure, wherein the thickness of SiC / Fe powder and Cu powder is 1.0-1.2 mm, and at the same time lay a layer of Ni powder at the interface between SiC / Fe powder and Cu powder, wherein the thickness of Ni powder is 0.1-0.15 mm, wherein the number of layers of Cu powder is n, the number of layers of SiC / Fe powder is n+1, and the number of layers of Ni powder is 2n, where n is a positive integer, and obtain the desired layered structure material by SPS sintering; Step 3: After SPS sintering to obtain a layered structure material, hot rolling is performed to obtain a high-performance Fe-Cu composite material.

2. The method for preparing a high-performance Fe-Cu composite material according to claim 1, characterized in that: The volume fraction of SiC particles in step 1 is 3%.

3. The method for preparing a high-performance Fe-Cu composite material according to claim 1, characterized in that: The mechanical ball milling time in the step 1 is 5-8 hours, and the rotation speed is 250 rpm.

4. The method for preparing a high-performance Fe-Cu composite material according to claim 1, characterized in that: In the step 1, the diameter of the Fe powder is 5-15 μm, and the diameter of the SiC particles is 3-5 μm.

5. The method for preparing a high-performance Fe-Cu composite material according to claim 1, characterized in that: In the step 2, the diameter of the Cu powder is 5-15 μm, and the diameter of the Ni powder is 3-5 μm.

6. The method for preparing a high-performance Fe-Cu composite material according to claim 1, characterized in that: In the step 2, the SPS sintering temperature is 850-950° C., the pressure is 40-50 MPa, and the holding time is 20-30 min.

7. The method for preparing a high-performance Fe-Cu composite material according to claim 1, characterized in that: The hot rolling in step 3 is specifically as follows: the hot rolling temperature is 900-1000° C., the deformation amount is 50-55%, the rolling amount per pass is 10%, a total of 5-6 passes are performed, and tempering is performed for 2-3 minutes between each pass.

8. A high performance Fe-Cu composite material prepared by the method of any one of claims 1 to 7.

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