In-situ synthesized layered Fe-Fe3Al composite material and preparation method thereof

Abstract

The application discloses in-situ synthesized layered Fe-Fe3Al composite material and a preparation method thereof, and belongs to the technical field of layered products composed of metals. The method comprises the following steps: (1) pretreatment, (2) room temperature rolling, (3) wrapping and compacting, and (4) high-temperature hot rolling. Based on the characteristics of Fe-Al diffusion reaction, the in-situ synthesized Fe-Fe3Al layered structure composite material has simple process, can realize industrial scale production, and does not need to prepare the material through the liquid solidification method, so that various metallographic defects in the solidification process are avoided. The application further provides a layered Fe-Fe3Al composite material. The non-uniform layered structure material can effectively realize spatial homogenization of local deformation when the material is stressed, so that coordination between two phases is realized when the material is deformed, and good strength and toughness are achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of layered products composed of metals, in particular to an in-situ synthesized layered Fe-Fe3Al composite material and a preparation method thereof. BACKGROUND

[0002] Intermetallic compounds mainly refer to compounds formed between metal elements or between metal elements and metalloid elements, which are characterized by stoichiometric components between elements, and the components can vary within a certain range to form a solid solution with the compound as the matrix. Intermetallic compounds not only have metal bonds, but also have covalent bonds, and the atomic bonding force is strong, which has high hardness, high melting point and excellent creep resistance, making intermetallic compounds have important research value in the fields of aviation materials and high-temperature structural materials. At present, the research system is concentrated in Ni-Al, Ti-Al and Fe-Al three aspects, among which Fe-Al system has a very broad application prospect due to its lower cost, which is 1 / 3 of stainless steel. In the Fe-Al intermetallic compound system, Fe3Al intermetallic compound has low density, high specific strength, good high-temperature performance, excellent oxidation resistance and sulfurization resistance, and low material cost, but its room temperature brittleness seriously restricts its development.

[0003] In the prior art, the toughness of Fe3Al is improved by alloying, such as adding Cr, B, Zr and other alloying elements, but the effect is very limited; or adding more ceramic particle reinforced materials such as Al2O3 and WC to obtain Fe3Al composite material with high compressive performance. For example, Chinese patent CN102139377A discloses a preparation method of layered FeAl-based composite material plate, which uniformly mixes aluminum matrix powder and ceramic particles, cold-presses into a shape, and then puts it into a vacuum hot-pressing furnace to obtain a ceramic particle reinforced aluminum-based composite material blank. The ceramic particle reinforced aluminum-based composite material blank is rolled into a thin plate and stacked with a pure iron plate alternately, and then subjected to hot pressing, hot rolling and heat treatment to obtain a layered FeAl composite material plate. However, these methods cannot effectively improve the tensile performance of the material. In addition, the current preparation methods of Fe3Al-based iron-aluminum alloys mainly include various forms of smelting and mechanical alloying method, but the as-cast alloy has many defects and the quality of the castings is difficult to control, and the metal material is easily oxidized during the ball milling process of the mechanical alloying method, resulting in the inclusion of oxides. SUMMARY

[0004] In view of the above-mentioned defects of the prior art, in the first aspect of the present application, a preparation method of a layered Fe-Fe3Al composite material is provided, which is simple in process and suitable for large-scale production, comprising the following steps:

[0005] (1) Pretreatment: prepare corresponding iron and aluminum sheets with a certain iron to aluminum molar ratio, randomly disperse and stack the two kinds of metal sheets to obtain a stacked blank;

[0006] (2) room temperature rolling: rolling the stacked blank, with one rolling recorded as one pass, folding the stacked blank along the rolling direction after each pass, and then rolling in the next pass; repeating the rolling until a predetermined pass is reached, to obtain an intermediate material;

[0007] (3) wrapping and compacting: wrapping the intermediate material with soft metal and compacting, to prevent the intermediate material from being oxidized in subsequent processing, to obtain a bulk material;

[0008] (4) high-temperature hot rolling: placing the bulk material in a certain temperature for heat preservation treatment, and immediately performing hot rolling after the treatment, with one hot rolling recorded as one pass, entering the next heat preservation-hot rolling cycle after each pass; repeating the heat preservation-hot rolling until a predetermined cycle number is reached, to obtain a layered Fe-Fe3Al composite material.

[0009] Preferably, in the step (1), the molar ratio of iron to aluminum is 5-7:1.

[0010] Controlling the molar ratio of iron to aluminum between 5-7:1 can control the volume ratio of Fe3Al to Fe in the final composite material between 1-2:1, achieving the desired design effect.

[0011] Preferably, in the step (2), the predetermined pass of rolling is 20-50 passes.

[0012] Further preferably, in each pass of rolling, the reduction in thickness of the stacked blank is 50%-70%.

[0013] Preferably, the specific method of the step (3) is as follows: taking a small piece of copper pipe, placing a circular copper sheet with the same size as the inner diameter of the copper pipe on the bottom surface, filling the intermediate material into the copper pipe, and placing another circular copper sheet on the upper surface, and compacting to obtain a bulk material, which is entirely wrapped by the copper layer, to prevent the intermediate material from being oxidized in subsequent processing.

[0014] Preferably, in the step (4), the temperature of the heat preservation treatment is 550-700℃, and the heat preservation time is 10-30min.

[0015] Preferably, in the step (4), the predetermined cycle number of the heat preservation-hot rolling is 2-5 times.

[0016] Further preferably, after the heat preservation-hot rolling to the predetermined cycle number, the cumulative reduction in thickness of the bulk material is 60%-80%.

[0017] In the second aspect of the present application, a layered Fe-Fe3Al composite material with good room temperature toughness and excellent tensile properties is provided, which is prepared by the method of the first aspect of the present application.

[0018] Based on the above technical solution, the inventive concept of the present application is to firstly stack Fe sheets and Al sheets and then roll them multiple times at room temperature without lubrication, the Fe sheets and Al sheets are subjected to severe plastic deformation along the rolling direction under the great pressure of rolling and are repeatedly stacked and thinned, Fe and Al are dispersed in layers, and the dispersed Fe-Al intermediate material is wrapped with Cu sheets and Cu tubes to prevent oxidation at high temperature; during the subsequent high-temperature holding process, Al is completely consumed and leaves defects such as pores, and forms a loose Fe-Fe3Al composite material with the remaining Fe, after rapid rolling after taking out, the defects disappear, and a dense Fe-Fe3Al layered composite material is obtained.

[0019] In addition, the process of the present application can be processed at a temperature higher than the melting point of Al, and the temperature affects the speed of the reaction and the products of the reaction, and the degree of softening of the metal when hot rolling is performed at the corresponding temperature, thereby affecting the difficulty of plastic deformation. During the process of accumulative roll-bonding (ARB) at room temperature, partial solid solution and reaction occur between Fe-Al, and are dispersed into interlaminar structure, under the constraint of this structure, Al will not flow out at a temperature above the melting point, but will diffuse to Fe and react with it during the holding process. Therefore, the present application can provide a wider range of process temperature selection.

[0020] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0021] The present application provides a preparation method of a layered Fe-Fe3Al composite material, based on the characteristics of Fe-Al diffusion reaction, in-situ synthesis of Fe-Fe3Al layered structure composite material, simple process, can realize industrial scale production, and does not need to prepare the material by liquid solidification, thereby avoiding various metallographic defects in the solidification process.

[0022] The present application provides a layered Fe-Fe3Al composite material, which can effectively realize the spatial homogenization of local deformation when the material is stressed, so that the material realizes the coordination between the two phases when deforming, and has good strength and toughness. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a light microscope photo of the layered Fe-Fe3Al composite material of Example 1;

[0024] Figure 2 It is the X-ray diffraction (XRD) result and standard card characteristic peak of the layered Fe-Fe3Al composite material of Example 1;

[0025] Figure 3Tensile stress-strain curve of the layered Fe-Fe3Al composite material of Example 1;

[0026] Figure 4 Optical microscope photograph of the layered Fe-Fe3Al composite material of Example 2;

[0027] Figure 5 X-ray diffraction (XRD) results and standard card characteristic peaks of the layered Fe-Fe3Al composite material of Example 2;

[0028] Figure 6 Tensile stress-strain curve of the layered Fe-Fe3Al composite material of Example 2. DETAILED DESCRIPTION

[0029] The application will be further described in the following examples without limiting the application to the described examples. The experimental methods in the following examples, for which no specific conditions are indicated, are selected according to the conventional methods and conditions, or according to the instructions of the commercial products.

[0030] In the following examples:

[0031] The specifications of the iron sheet and the aluminum sheet are both 100 mm x 50 mm x 0.5 mm.

[0032] Example 1

[0033] Preparation method of the layered Fe-Fe3Al composite material:

[0034] (1) Pretreatment: Take two aluminum sheets, weigh them, and prepare the corresponding mass of iron sheets according to the molar ratio of iron to aluminum of 5:1; randomly disperse and stack the iron sheets and aluminum sheets after polishing the surfaces to obtain a stacked blank;

[0035] (2) Room temperature rolling: The obtained stacked blank is rolled at room temperature, and each rolling is recorded as one pass. After each pass, the stacked blank is folded along the rolling direction, and then the next pass is performed. Repeat the rolling until 40 passes, and in each pass, the reduction in thickness of the stacked blank is between 50% and 70%, to obtain an intermediate material;

[0036] (3) Wrapping and compaction: Take a small section of copper pipe, place a circular copper sheet with the same size as the inner diameter of the copper pipe on the bottom surface, then fill the intermediate material into the copper pipe, and place another circular copper sheet on the upper surface, and compact to obtain a block material. The block material is entirely wrapped by the copper layer to prevent oxidation of the intermediate material during subsequent processing;

[0037] (4) High-temperature hot rolling: The block material is placed in a muffle furnace at 550°C and kept for 30 minutes. After the holding time is up, the block material is immediately taken out of the muffle furnace and hot rolled thin. One hot rolling is recorded as one pass. After each hot rolling pass, the next holding-hot rolling cycle is entered. This cycle is repeated 3 times. The cumulative reduction rate of the block material in the thickness direction is controlled to be 70% to obtain a layered Fe-Fe3Al composite material.

[0038] The microstructure of the layered Fe-Fe3Al composite material obtained in this embodiment was observed using a light microscope. Figure 1 It can be seen that after 40 cycles of room temperature rolling and 3 cycles of heat preservation-hot rolling, the material still maintains its non-uniform layered structure.

[0039] The obtained layered Fe-Fe3Al composite material was characterized by X-ray diffraction (XRD), such as... Figure 2 As shown, the correspondence of characteristic peaks indicates that the material contains two phases, Fe and Fe3Al, thus obtaining the composite material with the desired components.

[0040] Standard tensile specimens were prepared from layered Fe-Fe3Al composite materials, and their tensile properties were measured. Figure 3 The tensile stress-strain curve shows that its tensile strength is about 940 MPa and its elongation is about 7.8%, indicating good tensile properties and high strength and toughness.

[0041] The hardness of the polished layered Fe-Fe3Al composite material samples was tested using a Mag-H200 microhardness tester. A load of 500g was applied for 10 seconds, and measurements were taken at 10 independent random points. The average value of the results was taken. According to the test results, the alloy hardness of the layered Fe-Fe3Al composite material can reach 339.8HV0.5.

[0042] Example 2

[0043] Preparation method of layered Fe-Fe3Al composite material:

[0044] (1) Pretreatment: Take two aluminum sheets and weigh them. Prepare iron sheets of the corresponding mass according to the molar ratio of iron to aluminum of 5:1. After the iron sheets and aluminum sheets are polished and cleaned, they are randomly stacked to obtain a laminated blank.

[0045] (2) Room temperature rolling: The obtained laminated billet is rolled at room temperature. Each rolling pass is counted as one pass. After each pass, the laminated billet is folded in half along the rolling direction, and then the next pass is rolled. The rolling is repeated until 40 passes. In each pass, the reduction rate of the laminated billet in the thickness direction is between 50% and 70%, and intermediate material is obtained.

[0046] (3) wrapping compaction: take a small piece of copper tube, put a piece of copper sheet with the same size as the inner diameter of the copper tube on the bottom surface, then fill the intermediate material into the copper tube, and put another piece of copper sheet on the top surface, and compact to obtain a bulk material, which is entirely wrapped by the copper layer to prevent the intermediate material from being oxidized during subsequent processing;

[0047] (4) high-temperature hot rolling: the bulk material is placed in a muffle furnace at 700°C for heat preservation; immediately after the heat preservation time, the bulk material is taken out from the muffle furnace for hot rolling and thinning, and each hot rolling is recorded as one pass; after each pass of hot rolling, the next heat preservation-hot rolling cycle is entered, and the cycle is repeated 3 times; the heat preservation time of the first cycle is 30 min, and the heat preservation time of the second and third cycles is 10 min; the cumulative reduction rate of the bulk material in the thickness direction is controlled to be 65%, and a layered Fe-Fe3Al composite material is obtained.

[0048] The microstructure of the layered Fe-Fe3Al composite material obtained in this embodiment is observed by optical microscopy, and it can be seen from Figure 4 that after 30 passes of room temperature rolling and 3 times of heat preservation-hot rolling cycle, the material also maintains its non-uniform layered structure.

[0049] The layered Fe-Fe3Al composite material is characterized by X-ray diffraction (XRD), as shown in Figure 5 , and it can be seen from the corresponding relationship of the characteristic peaks that the material contains Fe and Fe3Al two-phase structures, and the required composite material is obtained.

[0050] The layered Fe-Fe3Al composite material is made into a standard tensile specimen and its tensile properties are measured, and the tensile stress-strain curve of Figure 6 can be seen that the tensile strength is about 930 MPa, and the elongation is about 7.9%, and the tensile properties are good, and the strength and toughness are high.

[0051] The polished layered Fe-Fe3Al composite material sample is tested for hardness by using a Miege-H200 microhardness tester, with a 500g load, a 10s holding time, and 10 independent random points are measured, and the average value is taken. According to the test results, the alloy hardness of the layered Fe-Fe3Al composite material can reach 328.0HV0.1.

[0052] Example 3

[0053] Method for preparing layered Fe-Fe3Al composite material:

[0054] (1) pretreatment: take 2 aluminum sheets, weigh them, and prepare the corresponding mass of iron sheets according to the molar ratio of iron to aluminum of 6:1; the iron sheets and aluminum sheets are randomly dispersed and stacked after being polished and cleaned, and a stacked blank is obtained;

[0055] (2) room temperature rolling: the obtained laminated blank is rolled at room temperature, and one rolling is recorded as one pass. After each pass, the laminated blank is folded along the rolling direction, and then the next pass is rolled. The rolling is repeated until 20 passes. In each pass, the reduction in thickness direction of the laminated blank is between 50% and 70%, and an intermediate material is obtained;

[0056] (3) wrapping and compaction: a small section of copper pipe is taken, a circular copper sheet with the same size as the inner diameter of the copper pipe is placed on the bottom surface, the intermediate material is filled into the copper pipe, and another circular copper sheet is placed on the upper surface, and the bulk material is obtained by compaction. The bulk material is entirely wrapped by the copper layer to prevent the intermediate material from being oxidized in subsequent processing;

[0057] (4) high-temperature hot rolling: the bulk material is placed in a muffle furnace at 600°C for heat preservation. After the heat preservation time, the bulk material is immediately taken out of the muffle furnace for hot rolling. One hot rolling is recorded as one pass. After each pass, the next heat preservation-hot rolling cycle is entered, and the cycle is repeated 3 times. The heat preservation time in each cycle is 20 min, and the cumulative reduction in thickness direction of the bulk material is controlled to be 80%, and a layered Fe-Fe3Al composite material is obtained.

[0058] Example 4

[0059] Preparation method of layered Fe-Fe3Al composite material:

[0060] (1) pretreatment: two aluminum sheets are taken, and their mass is measured. Iron sheets with a corresponding mass are prepared according to the molar ratio of iron to aluminum of 7:1. The iron sheets and aluminum sheets are randomly dispersed and stacked after being polished and cleaned, and a laminated blank is obtained;

[0061] (2) room temperature rolling: the obtained laminated blank is rolled at room temperature, and one rolling is recorded as one pass. After each pass, the laminated blank is folded along the rolling direction, and then the next pass is rolled. The rolling is repeated until 20 passes. In each pass, the reduction in thickness direction of the laminated blank is between 50% and 70%, and an intermediate material is obtained;

[0062] (3) wrapping and compaction: a small section of copper pipe is taken, a circular copper sheet with the same size as the inner diameter of the copper pipe is placed on the bottom surface, the intermediate material is filled into the copper pipe, and another circular copper sheet is placed on the upper surface, and the bulk material is obtained by compaction. The bulk material is entirely wrapped by the copper layer to prevent the intermediate material from being oxidized in subsequent processing;

[0063] (4) high-temperature hot rolling: the bulk material is placed in a muffle furnace at 650℃ for heat preservation; the bulk material is taken out from the muffle furnace immediately after the heat preservation time, and is hot-rolled to be thin, one hot rolling is recorded as one pass, after each pass of hot rolling, the next heat preservation-hot rolling cycle is entered, the cycle is repeated for 3 times, the heat preservation time in each cycle is 15 min, and the cumulative reduction in thickness direction of the bulk material is controlled to be 60%, to obtain a layered Fe-Fe3Al composite material.

[0064] The preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations without departing from the concept of the present application. Therefore, any technical solutions obtained by logical analysis, reasoning or limited experiments based on the prior art according to the concept of the present application shall be within the protection scope defined by the claims.

Claims

1. A method for producing a layered Fe-Fe3Al composite material, characterized by, Comprising the following steps: (1) Pretreatment: prepare corresponding iron sheet and aluminum sheet with a certain iron-aluminum molar ratio, randomly disperse and stack the two kinds of metal sheets to obtain a stacked blank; the molar ratio of iron and aluminum is 5-7:1; (2) Room temperature rolling: the stacked blank is rolled, and one rolling is recorded as one pass. After each pass, the stacked blank is folded along the rolling direction, and then the next pass is rolled. Repeat rolling until 20-50 passes. In each pass, the reduction in thickness of the stacked blank is 50-70%, and an intermediate material is obtained; (3) Wrapping and compaction: the intermediate material is wrapped with soft metal and compacted to prevent oxidation of the intermediate material during subsequent processing, and a bulk material is obtained; (4) High temperature hot rolling: the bulk material is subjected to heat treatment at a certain temperature, the heat treatment temperature is 550-700℃, and the heat treatment time is 10-30min. After treatment, hot rolling is immediately carried out, and one hot rolling is recorded as one pass. After each pass, the next heat treatment-hot rolling cycle is entered; Repeat the heat treatment-hot rolling for 2-5 times. After the bulk material is heat treated and rolled to the predetermined number of cycles, the cumulative reduction in thickness of the bulk material is 60-80%, and a layered Fe-Fe3Al composite material is obtained.

2. The method of claim 1, wherein: The specific method of step (3) is as follows: take a small piece of copper pipe, put a circular copper sheet with the same size as the inner diameter of the copper pipe on the bottom surface, then fill the intermediate material into the copper pipe, and put another circular copper sheet on the upper surface. Compaction to obtain a bulk material, the bulk material is wrapped with a copper layer to prevent oxidation of the intermediate material during subsequent processing.

3. A layered Fe-Fe3Al composite material, characterized by: Prepared by the method of claim 1 or 2.

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