A three-dimensional isotropic zero thermal expansion composite sheet and a warm rolling preparation method thereof

Abstract

This invention belongs to the field of low thermal expansion metal matrix composite material preparation technology, specifically relating to a three-dimensional isotropic zero thermal expansion composite sheet and its warm rolling preparation method. The method includes the following steps: ... 17 The powder was mixed with Fe-Mn alloy powder to obtain Dy2Fe 17 / Fe-Mn composite powder; then the Dy2Fe 17 Fe-Mn composite powder and Fe-36Ni Invar alloy powder are mixed uniformly at an atomic ratio of 1:1 and then filled into a metal casing. The mixture is then warm-rolled at 800 °C. After rolling, the surface casing is removed to obtain the composite sheet. Preferably, the Fe-Mn alloy powder is Fe... 70 Mn 30 The alloy powder is mixed uniformly using a conventional mixing method for 12 hours, and the metal sheath is a 20 steel sheath. This invention achieves the mixing of intrinsically anisotropic Dy2Fe... 17 The component transforms into a three-dimensional isotropic zero-thermal-expansion sheet material, which combines zero thermal expansion performance, directional consistency and mechanical properties. The process is simple and suitable for the preparation of sheet-like low-thermal-expansion composite materials.

Description

Technical Field

[0001] This invention belongs to the field of low thermal expansion metal matrix composite material preparation technology, specifically relating to a three-dimensional isotropic zero thermal expansion composite plate and its warm rolling preparation method. Background Technology

[0002] Low or zero thermal expansion materials have significant application value in precision instruments, electronic packaging, optical devices, aerospace, and cryogenic engineering. Although existing zero thermal expansion materials can exhibit low or even near-zero coefficients of thermal expansion within a certain temperature range, they generally suffer from insufficient plasticity, poor processability, and insufficient isotropy, thus limiting their engineering applications.

[0003] Dy2Fe 17 The base material has significant potential for thermal expansion control; by combining it with Fe-Mn alloys, low- or even zero-thermal-expansion composite systems can be formed. However, Dy2Fe 17 As an intermetallic compound exhibiting significant crystallographic anisotropy, its thermal expansion behavior is closely related to crystal orientation. It is generally easier to achieve zero or low thermal expansion in a specific direction, but difficult to achieve coordinated thermal expansion across multiple orthogonal directions. Therefore, existing Dy₂Fe... 17 Low thermal expansion materials mainly focus on uniaxial or specific directional control, but there is still a problem of insufficient consistency in thermal expansion in three dimensions.

[0004] In addition, there is existing Dy2Fe 17 Low thermal expansion materials are mainly concentrated in molten blocks or hot-pressed discs, and their plasticity, sheet material properties and engineering applicability still need to be improved.

[0005] Fe-36Ni Invar alloy is a typical low-thermal-expansion metallic material, while also possessing good plasticity and machinability. If Dy2Fe... 17 Further combining Fe-Mn zero-thermal-expansion composite powder with Fe-36Ni Invar alloy powder, and achieving powder core densification and sheet forming through warm rolling, is expected to weaken the Dy2Fe... 17 The intrinsic anisotropy has a directional effect in macroscopic sheet materials, thus taking into account zero thermal expansion performance, three-dimensional isotropy, and mechanical properties.

[0006] Among them, Fe 70 Mn 30 The introduction of alloy powder into the composite system described in this invention has distinctive features, as it interacts with Dy2Fe 17 The composite components can serve as a source of zero thermal expansion functional phases, and together with Fe-36Ni Invar alloy, they can be used to construct a composite plate system, thereby achieving synergistic optimization of thermal expansion performance and mechanical properties.

[0007] Therefore, it is necessary to develop a method that can weaken Dy2Fe 17 The intrinsic anisotropy influence and achievement of three-dimensional isotropic zero thermal expansion composite plates and their preparation methods are of great significance. Furthermore, how to control the macrostructure of composite materials through plastic forming processes to achieve Dy2Fe 17 Achieving coordination of intrinsic anisotropic negative thermal expansion in multiple orthogonal directions is a key technical problem that urgently needs to be solved. Summary of the Invention

[0008] To address the problems in existing technologies, this invention provides a three-dimensional isotropic zero-thermal-expansion composite sheet and its warm-rolling preparation method, which involves using Dy2Fe 17 By combining Fe-Mn zero-thermal-expansion composite powder with Fe-36Ni Invar alloy powder and incorporating a powder loading and warm rolling process, a composite material of Dy2Fe was achieved. 17 The transformation from intrinsic anisotropic negative thermal expansion to macroscopic three-dimensional isotropic zero thermal expansion sheet material, while simultaneously possessing good mechanical properties and sheet material formability, effectively solves the problem of Dy2Fe 17 The inherent anisotropy of thermal expansion in the base material makes it difficult to achieve multi-directional zero thermal expansion coordination. The plastic deformation and microstructure rearrangement introduced during warm rolling help to weaken the thermal expansion of Dy2Fe. 17 The directional effect of intrinsic anisotropy on a macroscopic scale enables the transformation from uniaxial zero thermal expansion to three-dimensional isotropic zero thermal expansion.

[0009] The technical solution of this invention is:

[0010] This invention provides a method for warm rolling preparation of a three-dimensional isotropic zero-thermal-expansion composite sheet, comprising the following steps:

[0011] Dy2Fe 17 The powder was mixed with Fe-Mn alloy powder to obtain Dy2Fe 17 / Fe-Mn composite powder; then the Dy2Fe 17 Fe-Mn composite powder and Fe-36Ni Invar alloy powder are mixed evenly and then filled into a metal cladding; the mixture is then warm rolled at 800℃. After rolling, the surface cladding is removed to obtain a composite plate; the composite plate has zero thermal expansion characteristics in three mutually orthogonal directions.

[0012] Preferably, in the above-mentioned warm rolling preparation method, the Dy2Fe 17 Powder and Fe-Mn alloy powder are mixed at an atomic ratio of 95:5, Dy2Fe 17 Fe-Mn composite powder and Fe-36Ni Invar alloy powder are mixed at an atomic ratio of 1:1.

[0013] Preferably, in the above-mentioned warm rolling preparation method, the Fe-Mn alloy powder is Fe 70Mn 30 The alloy powder is mixed evenly by a conventional mixing method, and the mixing time is 12 hours.

[0014] Preferably, in the above-mentioned warm rolling preparation method, the metal cladding is a steel cladding, and the steel cladding is a 20 steel cladding; the method of removing the surface cladding is mechanical removal, and the mechanical removal method is grinding removal.

[0015] Preferably, in the above-mentioned warm rolling preparation method, the warm rolling is performed in 5 passes, with a single pressing amount of 4 mm, the cladding thickness is rolled from 30 mm to 10 mm, and the powder core thickness inside the cladding is rolled from 10 mm to about 2 mm.

[0016] The present invention also provides a composite board prepared by the above method, wherein the composite board contains Dy2Fe 17 Phase and FCC phase, and Dy2Fe 17 The phase is dispersed in the FCC matrix.

[0017] Furthermore, the aforementioned composite material exhibits zero thermal expansion characteristics in the three mutually orthogonal directions of TD, ND, and RD.

[0018] Furthermore, the composite material described above exhibits an average coefficient of linear expansion of less than 2 × 10⁻⁶ in the TD, ND, and RD directions within the temperature range of -160 ℃ to 160 ℃. -6 K -1 In this invention, "zero thermal expansion" means that the absolute value of the average linear expansion coefficient of the material within a given temperature range is not higher than 10. -6 K -1 .

[0019] Furthermore, within the temperature range of -160 ℃ to 160 ℃, the average coefficient of linear expansion of the composite material in the TD, ND, and RD directions is approximately 0.93 × 10⁻⁶. -6 K -1 0.08×10 -6 K -1 and 0.26×10 -6 K -1 .

[0020] Furthermore, the compressive strength of the aforementioned composite material is 500–600 MPa. Furthermore, the three-dimensional isotropic zero thermal expansion behavior of the aforementioned composite material originates from Dy2Fe. 17 The synergistic compensation between the anisotropic negative thermal expansion of the phase and the positive thermal expansion of the FCC matrix is ​​achieved through the warm rolling process to regulate the microstructure.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention uses Dy2Fe 17 This paper presents a novel route for preparing low thermal expansion composite plates by combining Fe-Mn composite powder with Fe-36Ni Invar alloy powder and using a powder loading and warm rolling process.

[0023] (2) Dy2Fe 17 It inherently exhibits significant thermal expansion anisotropy; existing Dy2Fe 17 Low thermal expansion materials are more likely to achieve zero thermal expansion in a single direction; this invention utilizes Dy2Fe 17 The synergistic composite of Fe-Mn and Fe-36Ni Invar alloy, along with the control of the microstructure during warm rolling, resulted in a sheet material exhibiting zero thermal expansion characteristics in the three mutually orthogonal directions of TD, ND, and RD. This achieved a transformation from uniaxial zero thermal expansion to three-dimensional isotropic zero thermal expansion, effectively overcoming the limitations of Dy2Fe alloys. 17 The limitation of intrinsic anisotropy;

[0024] (3) The resulting composite board contains Dy2Fe 17 Phase and FCC phase, and Dy2Fe 17 The phase is dispersed in the FCC matrix, which is beneficial to achieving synergistic optimization of low thermal expansion performance and mechanical properties;

[0025] (4) The average linear expansion coefficients of the obtained composite board in the three directions of TD, ND and RD are approximately 0.93×10 in the range of -160 ℃ to 160 ℃. -6 K -1 0.08×10 -6 K -1 and 0.26×10 -6 K -1 All are less than 2×10 -6 K -1 It belongs to the category of zero thermal expansion materials and has three-dimensional isotropic thermal expansion properties;

[0026] (5) The compressive strength of the obtained composite board is about 550 MPa, and it has good compressive strain capacity, achieving a synergistic improvement in zero thermal expansion performance, directional consistency and mechanical properties;

[0027] (6) The comparative results show that, under the same warm rolling conditions of 800 °C as in Example 1, ball milling is used to refine Dy2Fe. 17 The average linear expansion coefficient in the ND direction of the sheet material obtained from the powder is significantly increased. The matching of raw material state and process parameters used in this invention is more conducive to obtaining three-dimensional isotropic zero thermal expansion performance.

[0028] (7) This invention not only achieves three-dimensional isotropic zero thermal expansion, but also enables the material to be prepared in sheet form, significantly improving its engineering processing applicability. It is particularly suitable for engineering scenarios such as precision structural parts or electronic packaging substrates with high requirements for dimensional stability and isotropy. Attached Figure Description

[0029] Figure 1 The figures show the thermal expansion curves of the composite material obtained in Example 1 of this invention in the three directions of TD, ND, and RD. It can be seen that Example 1 achieves isotropic ZTE at -160~160℃.

[0030] Figure 2 The image shows the compressive stress-strain curve of the composite plate obtained in Example 1 of this invention. It can be seen that the yield strength of Example 1 is 550 MPa, exhibiting excellent compressive plasticity.

[0031] Figure 3 The image shows the XRD pattern of the composite material obtained in Example 1 of this invention. It can be seen that Example 1 mainly consists of two phases: FCC and HCP.

[0032] Figure 4 The images show the SEM-BSE image and EDS analysis results of the composite board obtained in Example 1 of this invention. Light gray represents Dy2Fe. 17 The powder particles are dark gray and represent a Fe-36Ni matrix. Dy2Fe can be observed. 17 The powder particles are embedded in the plastic Fe-36Ni matrix, with good interfacial bonding, and line scanning shows that element diffusion is not obvious.

[0033] Figure 5 This is the thermal expansion curve of the composite material obtained in Comparative Example 1 of this invention in the ND direction. It can be seen that the coefficient of thermal expansion is as high as 6.02 × 10⁻⁶. -6 K -1 It does not meet the requirements for zero-expansion materials.

[0034] Figure 6 This is the XRD pattern of the composite material obtained in Comparative Example 1 of this invention. The XRD shows the reaction occurring at the interface. Compared with Comparative Example 1, Dy2Fe 17 The XRD peaks have largely disappeared, and some new phases, such as the BCC phase, have been generated.

[0035] Figure 7 The images show the SEM-BSE image, EDS line scan, and elemental surface mapping of the composite material obtained in Comparative Example 1 of this invention. As shown in Figure (ad), the dark gray areas represent Ni-rich particles. (See Figure (e) and...) Figure 6 The XRD pattern indicates an FCC phase within the Fe-36Ni phase; the light gray region is rich in Fe and Dy, but the combination... Figure 6 The XRD pattern is considered to be Dy2Fe.17 Phase decomposition occurs, and the coefficient of thermal expansion increases due to the failure of the NTE phase.

[0036] Figure 8 This is the compressive stress-strain curve of the composite material obtained in Comparative Example 1 of this invention. Figure 2 Compared to the compression curve of the previous figure, the compression curve in this figure shows brittle fracture. This is consistent with the microstructure of the Fe-36Ni matrix ( Figure 4 ) transforms into a brittle matrix rich in Fe and Dy ( Figure 7 )related. Detailed Implementation

[0037] The present invention will be further described below with reference to embodiments, but the scope of protection of the present invention is not limited thereto.

[0038] Example 1

[0039] In this embodiment, a method for warm rolling a three-dimensional isotropic zero-thermal-expansion composite sheet includes the following steps:

[0040] First, Dy2Fe 17 powder and Fe 70 Mn 30 Alloy powder was prepared at an atomic ratio of 95:5 to obtain Dy2Fe 17 / Fe-Mn composite powder. Then, the Dy2Fe... 17 Fe-Mn composite powder and Fe-36Ni Invar alloy powder were mixed at a 1:1 atomic ratio. The powders were then mixed using a standard mixing method for 12 hours to improve the uniformity of the mixture.

[0041] Subsequently, the uniformly mixed powder was loaded into a 20mm steel liner and warm rolled at 800°C. The rolling process consisted of 5 passes, with a single pass reduction of 4 mm. The total liner thickness was 30 mm before rolling, which was reduced to 10 mm after warm rolling; the powder core layer thickness was reduced from 10 mm to approximately 2 mm.

[0042] After rolling, the 20 steel cladding on the surface is removed by grinding to obtain the final composite plate sample.

[0043] The obtained composite board was subjected to thermal expansion testing, and the test results are as follows: Figure 1 As shown, the sample exhibits zero thermal expansion in the TD, ND, and RD directions. Specifically, within the temperature range of -160 ℃ to 160 ℃, the average linear expansion coefficients in the TD, ND, and RD directions are approximately 0.93 × 10⁻⁶. -6 K -1 0.08×10 -6 K -1 and 0.26×10 -6 K -1All are less than 2×10 -6 K -1 This indicates that the material belongs to the category of zero thermal expansion materials and has three-dimensional isotropic thermal expansion characteristics.

[0044] Due to Dy2Fe 17 It inherently exhibits significant anisotropy in thermal expansion. The above results indicate that by using Dy2Fe 17 By combining Fe-Mn composite powder with Fe-36Ni Invar alloy powder and implementing warm rolling microstructure control, the macroscopic thermal expansion directionality of the material can be significantly weakened, enabling the composite plate to reach the category of zero thermal expansion material in the TD, ND and RD directions, achieving three-dimensional isotropic zero thermal expansion.

[0045] The resulting composite board was subjected to compressive mechanical property testing, and the test results are as follows: Figure 2 As shown, its compressive strength is approximately 550 MPa, and the sample did not break under compression within a range of approximately 40% of the compressive strain, demonstrating good compressive strain capacity.

[0046] XRD results are as follows Figure 3 As shown, Dy2Fe is present in the sample. 17 The presence of the FCC phase indicates the formation of a multiphase composite structure after warm rolling. SEM and EDS results are as follows: Figure 4 As shown, the light-colored particle areas in the composite board are rich in Dy, which, combined with XRD, can be identified as Dy2Fe. 17 The matrix region is rich in Fe and Ni, and can be identified as the Fe-36Ni FCC phase.

[0047] The implementation results show that the present invention, through Dy2Fe 17 By combining Fe-Mn composite powder with Fe-36Ni Invar alloy powder and implementing warm rolling microstructure control, it is possible to prepare composite plates that possess three-dimensional isotropic zero thermal expansion, high compressive strength, and good compressive strain capacity. Furthermore, this process achieves the desired microstructure from Dy2Fe... 17 The performance transformation from intrinsic anisotropic thermal expansion components to macroscopically isotropic zero thermal expansion sheet materials.

[0048] To compare Dy2Fe 17 The influence of powder raw material state on the thermal expansion properties and microstructure of the resulting composite plate was investigated by setting up the following comparative examples, while maintaining the raw material system, proportions, and subsequent warm rolling processes as basically consistent.

[0049] Comparative Example 1

[0050] This comparative example uses the same raw material system, proportions, and warm rolling process as Example 1 to prepare composite plates, wherein Dy2Fe 17The ratio of Fe-Mn composite powder to Fe-36Ni Invar alloy powder remains unchanged. The difference lies in: first, the Dy2Fe... 17 The powder was ball-milled to refine it, and then mixed with Fe. 70 Mn 30 The alloy powders were mixed to obtain Dy2Fe. 17 / Fe-Mn composite powder was prepared by subsequent warm rolling under the same conditions as in Example 1.

[0051] Thermal expansion test results are as follows Figure 5 As shown, within the temperature range of -160 ℃ to 160 ℃, the average linear expansion coefficient in the ND direction of the sheet material obtained in this comparative example is approximately 6.02 × 10⁻⁶. -6 K -1 The results were significantly higher than in Example 1. The XRD results are as follows: Figure 6 As shown, Dy2Fe is present in the sample. 17 Phases including FCC and BCC phases, and containing a small amount of unknown phases; SEM and EDS results are as follows. Figure 7 As shown, FeNi-rich particles in the sample are dispersed within a Dy-rich matrix. Compression test results are as follows... Figure 8 As shown, the sheet still has high compressive strength, but its compression curve shows no plasticity compared to Example 1, which is consistent with... Figure 7 organization Figure 1 To.

[0052] Analysis suggests that the ball-milled Dy2Fe 17 The reduced particle size, increased specific surface area, and improved activity of the powder make it more prone to changes in microstructure and phase composition under the same 800 °C warm rolling conditions as in Example 1, thus making it difficult to maintain the low thermal expansion microstructure state corresponding to Example 1. These results indicate that, under the same 800 °C warm rolling conditions as in Example 1, ball milling to refine Dy2Fe... 17 Powder is not conducive to obtaining the three-dimensional isotropic zero thermal expansion properties described in Example 1.

Claims

1. A method for warm rolling a three-dimensional isotropic zero-thermal-expansion composite sheet, characterized in that, The steps include: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] 17 The powder was mixed with Fe-Mn alloy powder to obtain Dy2Fe 17 / Fe-Mn composite powder; then the Dy2Fe 17 Fe-Mn composite powder and Fe-36Ni Invar alloy powder are mixed evenly and then filled into a metal cladding; the mixture is then warm rolled at 800℃. After rolling, the surface cladding is removed to obtain a composite plate; the composite plate has zero thermal expansion characteristics in three mutually orthogonal directions.

2. The warm rolling preparation method according to claim 1, characterized in that, The Dy2Fe 17 Powder and Fe-Mn alloy powder are mixed at an atomic ratio of 95:5, Dy2Fe 17 Fe-Mn composite powder and Fe-36Ni Invar alloy powder are mixed at an atomic ratio of 1:

1.

3. The warm rolling preparation method according to claim 1, characterized in that, The Fe-Mn alloy powder is Fe 70 Mn 30 The alloy powder is mixed evenly by a conventional mixing method, and the mixing time is 12 hours.

4. The warm rolling preparation method according to claim 1, characterized in that, The metal sheath is a steel sheath, and the steel sheath is a 20 steel sheath; the method of removing the surface sheath is mechanical removal, and the mechanical removal method is grinding removal.

5. The warm rolling preparation method according to claim 1, characterized in that, The warm rolling process is carried out in 5 passes, with a single rolling pressure of 4 mm. The cladding thickness is rolled from 30 mm to 10 mm, and the powder core thickness inside the cladding is rolled from 10 mm to approximately 2 mm.

6. A three-dimensional isotropic zero-thermal-expansion composite sheet material prepared by the method according to any one of claims 1 to 5, characterized in that, The composite board contains Dy2Fe 17 Phase and FCC phase, and the Dy2Fe 17 The phase is dispersed in the FCC matrix; the composite material exhibits zero expansion characteristics in the three mutually orthogonal directions TD, ND and RD.

7. The composite board according to claim 6, characterized in that, Within the temperature range of -160 ℃ to 160 ℃, the average coefficient of linear expansion of the composite material in the TD, ND, and RD directions is less than 2×10. -6 K -1 .

8. The composite board according to claim 7, characterized in that, Within the temperature range of -160 ℃ to 160 ℃, the average linear expansion coefficients of the composite material in the TD, ND, and RD directions are approximately 0.93 × 10⁻⁶. -6 K -1 0.08×10 -6 K -1 and 0.26×10 -6 K -1 .

9. The composite board according to claim 6, characterized in that, The compressive strength of the composite board is 500-600 MPa.

10. The composite board according to claim 6, characterized in that, The three-dimensional isotropic zero thermal expansion behavior originates from Dy2Fe 17 The synergistic compensation between the anisotropic negative thermal expansion of the phase and the positive thermal expansion of the FCC matrix is ​​achieved through the warm rolling process to regulate the microstructure.

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