Raw material composition of constant-expansion alloy, constant-expansion alloy and preparation method and application of constant-expansion alloy
By preparing fixed-expansion alloys of nickel, silicon, rare earth metals and iron, the problem of insufficient thermal expansion coefficient range of fixed-expansion alloys in the prior art is solved, and an extremely narrow thermal expansion coefficient within different temperature ranges is achieved to meet the application needs of high strength and high hardness.
Patent Information
- Application Number
- CN202411694010.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-03-28
AI Technical Summary
The thermal expansion coefficients of existing fixed expansion alloys in the range of 30-350℃ and 30-500℃ cannot meet the needs of the application end, and there is a very narrow range of thermal expansion coefficients.
By preparing a fixed-expanded alloy raw material composition of nickel, silicon, rare earth metal and iron, the specific content ranges from 45 wt% to 50 wt% nickel, 0.5 wt% to 1.5 wt% of silicon, and 0.1 wt% to 0.8 wt% rare earth metal, and by smelting, forging, annealing and aging treatment, a fixed-expanded alloy with an extremely narrow thermal expansion coefficient range is prepared.
It is achieved that the thermal expansion coefficient range of fixed expansion alloys is extremely narrow in the range of 30-350℃ and 30-500℃, with high strength and high hardness, which meets the high elastic modulus requirements at the application end, and effectively avoids the problem of warping or collapse in applications.
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Abstract
Description
Technical Field
[0001] The invention specifically relates to a raw material composition of a constant expansion alloy, a constant expansion alloy and a preparation method and application thereof. Background Art
[0002] Constant expansion alloys are alloys with a relatively constant coefficient of thermal expansion, also known as sealing alloys or Kovar alloys. These alloys are designed to maintain stable dimensions when the temperature changes to meet the high precision and high stability requirements of specific applications. Constant expansion alloys have a wide range of applications and can meet demanding precision engineering applications such as aerospace, semiconductor manufacturing, medical devices and other fields that require high stability and accuracy.
[0003] Constant expansion alloys are usually composed of metal elements such as nickel, iron, and cobalt. The required low thermal expansion coefficient, yield strength, and hardness are achieved by precisely controlling the alloy composition and processing technology. The main types are iron-nickel, iron-nickel-cobalt, and iron-nickel-chromium alloys. The characteristic of constant expansion alloys is that the expansion coefficient is close to that of the sealed materials such as glass or ceramics within a certain temperature range, thereby achieving a matching sealing effect. The so-called matching package means that the difference in expansion coefficient between the alloy and the sealed material is less than 10% within the range from sealing temperature to room temperature. By precisely matching the thermal expansion coefficients of these materials, it can be ensured that during the manufacturing and use process, the various components in the package will not generate excessive stress due to thermal expansion differences, thereby avoiding cracks or fractures that may cause package failure. Therefore, in specific usage scenarios, the alloy material is required to have a certain range of thermal expansion coefficients. A thermal expansion coefficient that is too small or too large cannot meet the usage scenario.
[0004] The semiconductor industry has very strict requirements for materials, especially for materials used to manufacture semiconductor devices. High-strength constant expansion alloy is a special alloy that has good mechanical strength and a specific thermal expansion coefficient, which is critical for precise control and stability in the semiconductor manufacturing process. The applications of high-strength constant expansion alloys in semiconductors include but are not limited to: wafer fixtures and frames, vacuum chamber structural parts, precision positioning and guiding systems, high-temperature furnaces and heat treatment equipment. Selecting a suitable high-strength constant expansion alloy requires considering multiple factors, including operating temperature range, mechanical strength requirements, corrosion resistance, cost, and compatibility with semiconductor materials. Manufacturers usually customize alloy composition and properties according to specific application requirements. Summary of the invention
[0005] The present invention mainly aims to overcome the defect that the thermal expansion coefficient of the constant expansion alloy in the range of 30-350°C and 30-500°C in the prior art cannot meet the needs of the application end, and provides a raw material composition of a constant expansion alloy, a constant expansion alloy and a preparation method and application thereof. The constant expansion alloy provided by the present invention has an extremely narrow thermal expansion coefficient range in the range of 30-350°C and 30-500°C.
[0006] In order to overcome the above technical problems, the present invention provides the following technical solutions.
[0007] The present invention provides a raw material composition of a constant expansion alloy, which comprises the following components by mass:
[0008] Nickel: 45 wt%-50wt%;
[0009] Silicon: 0.5 wt%-1.5wt%;
[0010] Rare earth metal: 0.1 wt%-0.8 wt%; the rare earth metal is one or more of lanthanum, cerium and yttrium;
[0011] Impurity elements: 0.02 wt%-0.1 wt%; and the balance is iron;
[0012] The above percentage refers to the percentage of the mass of each element in the mass of the raw material composition of the fixed expansion alloy.
[0013] In the present invention, the nickel content in the raw material composition may be 45 wt%, 48 wt% or 50 wt%.
[0014] In the present invention, the silicon content in the raw material composition may be 0.5 wt%, 0.65 wt% or 1.5 wt%.
[0015] In the present invention, the content of rare earth metal in the raw material composition may be 0.2 wt%-0.8 wt%, for example, 0.2 wt%, 0.5 wt% or 0.8 wt%.
[0016] In the present invention, the impurity element may be one or more of phosphorus, sulfur and carbon.
[0017] In some preferred embodiments, the rare earth metal is lanthanum.
[0018] In the present invention, the purity of nickel in the raw material composition is greater than 99.9%.
[0019] In the present invention, the purity of iron in the raw material composition is greater than 99.9%.
[0020] In the present invention, the purity of silicon in the raw material composition is greater than 99.9%.
[0021] In the present invention, the impurity content in the iron-nickel alloy may be 0.02 wt%-0.05 wt%.
[0022] In some specific embodiments, the raw material composition includes the following components in mass content: nickel 48wt%, silicon 0.65wt%, lanthanum 0.1wt%-0.8wt%, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe.
[0023] In some specific embodiments, the raw material composition includes the following components in mass content: 46 wt % nickel, 1.0 wt % silicon, 0.5 wt % lanthanum, 0.02 wt % to 0.05 wt % impurity elements and the balance iron.
[0024] In some specific embodiments, the raw material composition includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.5 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0025] In some specific embodiments, the raw material composition includes the following components in mass contents: 45 wt % nickel, 0.65 wt % silicon, 0.5 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0026] In some specific embodiments, the raw material composition includes the following components in mass contents: 50 wt % nickel, 0.65 wt % silicon, 0.5 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0027] In some specific embodiments, the raw material composition includes the following components in mass contents: 48 wt % nickel, 0.5 wt % silicon, 0.5 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0028] In some specific embodiments, the raw material composition includes the following components in mass contents: 48wt% nickel, 1.5wt% silicon, 0.5wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe.
[0029] In some specific embodiments, the raw material composition includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.2 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0030] In some specific embodiments, the raw material composition includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.8 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0031] In some specific embodiments, the raw material composition includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.1 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0032] In some specific embodiments, the raw material composition includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.5 wt % cerium, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0033] In some specific embodiments, the raw material composition includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.5 wt % yttrium, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0034] The present invention provides a method for preparing a constant expansion alloy, which comprises the following steps:
[0035] (1) melting the raw material composition of the fixed expansion alloy as described above to obtain an iron-nickel alloy;
[0036] (2) The iron-nickel alloy is subjected to forging, annealing and aging treatment in sequence to obtain the constant expansion alloy.
[0037] In the present invention, the preparation method of the raw material composition can be: firstly melt the mixture of metallic nickel, metallic iron and elemental silicon, and then add the rare earth metal.
[0038] The melting is preferably carried out under vacuum conditions, with a vacuum degree of less than 10Pa.
[0039] In step (1), the smelting power may be 70 kW-95 kW, for example 95 kW.
[0040] In some specific embodiments, the smelting power is 70 kW-90 kW.
[0041] In step (1), the smelting method may be vacuum medium frequency induction smelting.
[0042] In step (1), the smelting temperature may be 1500°C-1800°C, for example 1600°C.
[0043] In step (1), the iron-nickel alloy is generally cast.
[0044] In step (2), the forging temperature may be 1000°C-1300°C, for example 1250°C.
[0045] In step (2), the forging time may be 2h-4h, for example 2h.
[0046] In step (2), after forging and before annealing, rolling is further performed, and the rolling includes hot rolling and cold rolling;
[0047] Preferably, the hot rolling temperature may be 1000°C-1300°C, more preferably 1000-1200°C.
[0048] Preferably, the hot rolling time is 2h-4h, for example 2h.
[0049] Preferably, the deformation amount of a single pass of the hot rolling may be 20%-35%, preferably 20%-35%, for example 25%-30%.
[0050] Preferably, the total deformation of the hot rolling may be greater than 70%, such as 85%.
[0051] Preferably, the deformation amount of a single pass of the cold rolling may be 25%-35%.
[0052] Preferably, the total deformation of the cold rolling may be greater than 60%, preferably 60%-90%, for example 70%.
[0053] Preferably, pickling is generally performed after hot rolling and before cold rolling.
[0054] In the present invention, the calculation method of the single-pass deformation amount is: single-pass deformation amount = (thickness before rolling of the pass - thickness after rolling of the pass) / thickness before rolling of the pass.
[0055] In the present invention, the total deformation is calculated as follows: total deformation = (thickness after all rolling passes - thickness before rolling) / thickness before rolling.
[0056] In step (2), the annealing temperature may be 800°C-1000°C, preferably 800°C-950°C, for example 850°C.
[0057] In step (2), the annealing time may be 2 h-4 h, for example 2 h.
[0058] In step (2), the pressure of the aging treatment may be 1 ton to 2 tons, for example, 2 tons.
[0059] In step (2), the temperature of the aging treatment may be 500°C-900°C, preferably 500°C-700°C, for example 650°C.
[0060] In step (2), the aging treatment time may be 3 days to 10 days, preferably 6 days to 9 days, for example 7 days.
[0061] The invention provides a constant expansion alloy, which is prepared by the preparation method as described above.
[0062] In the present invention, the constant expansion alloy comprises the following components by mass:
[0063] Nickel: 45 wt%-50wt%;
[0064] Silicon: 0.5 wt%-1.5wt%;
[0065] Rare earth metal: 0.1 wt%-0.8 wt%; the rare earth metal is one or more of lanthanum, cerium and yttrium;
[0066] Impurity elements: 0.02 wt%-0.1 wt%; and the balance is iron;
[0067] The above percentages refer to the percentage of the mass of each element to the mass of the fixed expansion alloy.
[0068] In the present invention, the average grain size of the constant expansion alloy is 20 μm-40 μm, for example, 30 μm.
[0069] In the present invention, the nickel content in the fixed expansion alloy may be 45wt%, 48wt% or 50wt%.
[0070] In the present invention, the silicon content in the fixed expansion alloy may be 0.5wt%, 0.65wt% or 1.5wt%.
[0071] In the present invention, the content of rare earth metal in the fixed expansion alloy may be 0.2 wt%-0.8 wt%, for example, 0.2wt%, 0.5wt% or 0.8wt%.
[0072] In the present invention, the impurity element may be one or more of phosphorus, sulfur and carbon.
[0073] In some preferred embodiments, the rare earth metal is lanthanum.
[0074] In the present invention, the purity of nickel in the fixed expansion alloy is greater than 99.9%.
[0075] In the present invention, the purity of iron in the fixed expansion alloy is greater than 99.9%.
[0076] In the present invention, the purity of silicon in the fixed expansion alloy is greater than 99.9%.
[0077] In the present invention, the impurity content in the fixed expansion alloy may be 0.02 wt%-0.05 wt%.
[0078] In some specific embodiments, the fixed expansion alloy includes the following components in mass content: 48wt% nickel, 0.65wt% silicon, 0.1wt%-0.8wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe.
[0079] In some specific embodiments, the fixed expansion alloy includes the following components in mass content: 46 wt % nickel, 1.0 wt % silicon, 0.5 wt % lanthanum, 0.02 wt % to 0.05 wt % impurity elements, and the balance Fe.
[0080] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.5 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0081] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 45wt% nickel, 0.65wt% silicon, 0.5wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe.
[0082] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 50wt% nickel, 0.65wt% silicon, 0.5wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe.
[0083] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 48 wt % nickel, 0.5 wt % silicon, 0.5 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0084] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 48 wt % nickel, 1.5 wt % silicon, 0.5 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0085] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.2 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0086] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.8 wt % lanthanum, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0087] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 48wt% nickel, 0.65wt% silicon, 0.1wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe.
[0088] In some specific embodiments, the constant expansion alloy includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.5 wt % cerium, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0089] In some specific embodiments, the fixed expansion alloy includes the following components in mass contents: 48 wt % nickel, 0.65 wt % silicon, 0.5 wt % yttrium, P<0.01 wt %, S<0.02 wt %, C<0.03 wt %, and the balance Fe.
[0090] The present invention provides the use of the above-mentioned constant expansion alloy in semiconductor vacuum chamber structural parts.
[0091] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.
[0092] The reagents and raw materials used in the present invention are commercially available.
[0093] The positive and progressive effects of the present invention are:
[0094] The thermal expansion coefficient α of the constant expansion alloy provided by the present invention is 30 350℃ 7.0×10 -6 / K-8.0×10 -6 / K、α 30 500℃ 8.0×10 -6 / K-9.0×10 -6 / K, its expansion coefficient range is extremely narrow, and it has high strength and hardness, which can meet the needs of high elastic modulus at the application end.
[0095] The preparation method of the constant expansion alloy provided by the present invention can refine the grains of the alloy, eliminate the internal stress of the material, and effectively avoid the problem of warping or collapse at the application end. BRIEF DESCRIPTION OF THE DRAWINGS
[0096] Figure 1 This is the metallographic diagram of the constant expansion alloy prepared in Example 1.
[0097] Figure 2 This is a hardness data diagram of the constant expansion alloy prepared in Example 1.
[0098] Figure 3 is the thermal expansion coefficient of the constant expansion alloy prepared in Example 1. DETAILED DESCRIPTION
[0099] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.
[0100] Example 1
[0101] A constant expansion alloy, comprising, by weight percentage: Ni: 48wt%, Si: 0.65wt%, La: 0.5wt%, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; the preparation method thereof is as follows:
[0102] (1) Weigh the main raw materials 3N6 nickel (purity greater than 99.96%), 3N iron (purity greater than 99.9%), and 4N silicon (purity greater than 99.99%) according to the above weight percentages, use an alumina crucible for vacuum induction melting, the vacuum degree is less than 10Pa, the melting power is 95kW, the melting temperature is 1600°C, after the iron and nickel are completely melted, use a secondary feeding bin to add 0.5wt% lanthanum, refine for 10min and then cast to obtain a Φ250*900mm iron-nickel alloy ingot;
[0103] (2) The iron-nickel alloy ingot obtained in step (1) is subjected to forging, hot rolling, cold rolling, recrystallization annealing and aging treatment in sequence to obtain a constant expansion alloy; wherein the forging temperature is 1250°C, the holding time is 2h, and the size of the ingot after forging is 2000*260*80mm; the forged ingot is hot rolled, the hot rolling temperature is 1200°C, the holding time is 2h, the deformation amount of each pass is 25-35%, and the total deformation amount is 85%; the cold rolling deformation amount is 70%; the annealing temperature is 850°C, the holding time is 2h; the aging treatment temperature is 650°C, the aging treatment time is 7d, and the aging treatment pressure is 2 tons.
[0104] Figure 1This is a metallographic image of the constant expansion alloy prepared in Example 1. It can be seen that the grains of the constant expansion alloy prepared are small and uniform in size, with an average grain size of 30 μm. Figure 2 This is the hardness variation curve of the constant expansion alloy obtained through 9 parallel tests in Example 1. It can be seen that the constant expansion alloy of the present invention has a high hardness between 235-255 HV, and the average hardness value obtained through 9 parallel tests is 247.4 HV. Figure 3 This is a curve obtained by testing the thermal expansion coefficient of the fixed expansion alloy gold in Example 1, where the ordinate is dL / L×10 -3 The horizontal axis represents temperature T, and the α of Example 1 is calculated by 1 / L·dL / dT. 30-350℃ 7.88×10 -6 / K,α 30-500℃ 8.86×10 -6 / K.
[0105] The types and amounts of various raw materials used in the preparation of the graphite material fixed expansion alloys in Examples 1-10 and Comparative Examples 1-5 are shown in Table 1:
[0106] Table 1
[0107]
[0108] Effect Example
[0109] 1. Thermal expansion coefficient
[0110] The thermal expansion coefficient was measured at 30-350°C and 30-500°C using a thermal expansion coefficient tester, and the results were calculated using the following formula and are recorded in Table 2.
[0111] Coefficient of thermal expansion ∝=1 / L·dL / dT.
[0112] 2. Grain size
[0113] The average grain size was obtained by metallographic microscope using the intercept method.
[0114] 3. Hardness
[0115] Via the Vickers hardness tester, the hardness result is directly read out, and 9 tests are performed to obtain the average value.
[0116] Table 2
[0117]
[0118] The present invention adjusts the alloy formula to meet the thermal expansion coefficient of 7.0×10 -6 / K-8.0×10 -6 / K; in the range of 30℃-500℃, the thermal expansion coefficient is 8.0×10 -6 / K-9.0×10 -6 / K, its expansion coefficient is extremely narrow, and it further has the advantages of uniform grain size and good mechanical properties.
[0119] The nickel content of Comparative Example 1 and Comparative Example 2 is not within the protection scope of the present invention. The nickel content of Comparative Example 1 is relatively low, while the nickel content of Comparative Example 2 is relatively high, which have a significant impact on the thermal expansion coefficient and cannot solve the technical problem of the present invention.
[0120] The silicon contents of Comparative Examples 3 and 4 are not within the protection scope of the present invention. The silicon content of Comparative Example 3 is relatively low, while the silicon content of Comparative Example 4 is relatively high, which have a significant impact on the thermal expansion coefficient and cannot solve the technical problem of the present invention.
[0121] The lanthanum content of Comparative Example 5 is not within the scope of protection of the present invention, and its lanthanum content is relatively high, which has a significant impact on the thermal expansion coefficient and cannot solve the technical problem of the present invention. This may be because the metal lanthanum acts as a crystal nucleus during the recrystallization process, increases the nucleation rate, and refines the grains, thereby affecting the thermal expansion coefficient.
[0122] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.
Claims
1. A raw material composition for a fixed expansion alloy, characterized in that: It includes the following components by mass: Nickel: 45 wt%-50wt%; Silicon: 0.5 wt%-1.5wt%; Rare earth metal: 0.1 wt%-0.8 wt%; the rare earth metal is one or more of lanthanum, cerium and yttrium; Impurity elements: 0.02 wt%-0.1 wt%; and the balance is iron; The above percentages refer to the percentage of the mass of each element in the mass of the raw material composition of the fixed expansion alloy.
2. The raw material composition according to claim 1, characterized in that The raw material composition satisfies one or more of the following conditions ad: a. The nickel content is 45wt%, 48wt% or 50 wt%; b. The silicon content is 0.5wt%, 0.65wt% or 1.5 wt%; c. The rare earth metal content is 0.2wt%-0.8wt%; d. The rare earth metal is lanthanum.
3. The raw material composition according to claim 1, characterized in that The raw material composition satisfies any one of the following conditions a1: a. The raw material composition comprises the following components by mass content: nickel 48wt%, silicon 0.65wt%, lanthanum 0.2 wt%-0.8wt%, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; b. The raw material composition comprises the following components by mass content: 46wt% nickel, 1.0wt% silicon, 0.5wt% lanthanum, 0.02wt% to 0.05wt% impurity elements and the balance iron; c. The raw material composition comprises the following components by mass: 48wt% nickel, 0.65wt% silicon, 0.5wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; d. The raw material composition comprises the following components by mass: 45wt% nickel, 0.65wt% silicon, 0.5wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; e. The raw material composition comprises the following components by mass content: 50wt% nickel, 0.65wt% silicon, 0.5wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; f. The raw material composition comprises the following components by mass content: 48wt% nickel, 0.5wt% silicon, 0.5wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; g. The raw material composition comprises the following components by mass: 48wt% nickel, 1.5wt% silicon, 0.5 wt% lanthanum, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; h. The raw material composition comprises the following components by mass: 48wt% nickel, 0.65wt% silicon, 0.2 wt% lanthanum, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; i. The raw material composition comprises the following components by mass: 48wt% nickel, 0.65wt% silicon, 0.8wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; j. The raw material composition comprises the following components by mass: 48wt% nickel, 0.65wt% silicon, 0.1 wt% lanthanum, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; k. The raw material composition comprises the following components by mass: 48wt% nickel, 0.65wt% silicon, 0.5wt% cerium, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; 1. The raw material composition includes the following components by mass: 48wt% nickel, 0.65wt% silicon, 0.5wt% yttrium, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe.
4. A method for preparing a constant expansion alloy, characterized in that: It includes the following steps: (1) Smelting the raw material composition of the fixed expansion alloy according to any one of claims 1 to 3 to obtain an iron-nickel alloy; (2) The iron-nickel alloy is subjected to forging, annealing and aging treatment in sequence to obtain the constant expansion alloy.
5. The method for preparing the constant expansion alloy according to claim 4, characterized in that: The method for preparing the fixed expansion alloy satisfies one or more of the following conditions af: a. The smelting power is 70kW-95kW; b. The smelting method is vacuum medium frequency induction melting; c. The smelting temperature is 1500°C-1800°C; d. The forging temperature is 1000°C-1300°C; e. The forging time is 2h-4h; f. After the forging and before the annealing, rolling is performed, wherein the rolling includes hot rolling and cold rolling; Wherein, the hot rolling temperature is 1000°C-1300°C; and the hot rolling time is 2h-4h.
6. The method for preparing the constant expansion alloy according to claim 4, characterized in that: The method for preparing the fixed expansion alloy satisfies one or more of the following conditions ae: a. The annealing temperature is 800°C-1000°C; b. The annealing time is 2h-4h; c. The aging treatment pressure is 1 ton to 2 tons; d. The aging treatment temperature is 500°C-900°C; e. The aging treatment time is 3d-10d.
7. A constant expansion alloy, characterized in that: The constant expansion alloy is prepared by the method for preparing the constant expansion alloy according to any one of claims 4 to 6.
8. The constant expansion alloy according to claim 7, characterized in that: The constant expansion alloy satisfies one or two of the following conditions ab: a. The fixed expansion alloy comprises the following components by mass: Nickel: 45 wt%-50wt%; Silicon: 0.5 wt%-1.5wt%; Rare earth metal: 0.1 wt%-0.8 wt%; the rare earth metal is one or more of lanthanum, cerium and yttrium; Impurity elements: 0.02 wt%-0.1 wt%; and the balance is iron; The percentage of each element mentioned above refers to the percentage of the mass of each element to the mass of the fixed expansion alloy; b. The average grain size of the constant expansion alloy is 20 μm-40 μm.
9. The constant expansion alloy according to claim 7, characterized in that: The constant expansion alloy satisfies any one of the following conditions a1: a. The fixed expansion alloy comprises the following components by mass content: nickel 48wt%, silicon 0.65wt%, lanthanum 0.2 wt%-0.8wt%, P <0.01wt%, S <0.02wt%, C <0.03wt%, and the balance Fe; b. The fixed expansion alloy comprises the following components by mass content: 46wt% nickel, 1.0wt% silicon, 0.5 wt% lanthanum, 0.02 wt% to 0.05 wt% impurity elements and the balance iron; c. The fixed expansion alloy comprises the following components by mass content: 48wt% nickel, 0.65wt% silicon, 0.5 wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; d. The fixed expansion alloy comprises the following components by mass content: nickel 45wt%, silicon 0.65wt%, lanthanum 0.5 wt%, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; e. The fixed expansion alloy comprises the following components by mass content: 50wt% nickel, 0.65wt% silicon, 0.5wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; f. The fixed expansion alloy comprises the following components by mass content: nickel 48wt%, silicon 0.5wt%, lanthanum 0.5 wt%, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; g. The fixed expansion alloy comprises the following components by mass content: nickel 48wt%, silicon 1.5wt%, lanthanum 0.5 wt%, P <0.01wt%, S <0.02wt%, C <0.03wt%, and the balance Fe; h. The fixed expansion alloy comprises the following components by mass content: 48wt% nickel, 0.65wt% silicon, 0.2 wt% lanthanum, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; i. The fixed expansion alloy comprises the following components by mass content: 48wt% nickel, 0.65wt% silicon, 0.8 wt% lanthanum, P < 0.01wt%, S < 0.02wt%, C < 0.03wt%, and the balance Fe; j. The fixed expansion alloy comprises the following components by mass content: 48wt% nickel, 0.65wt% silicon, 0.1 wt% lanthanum, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; k. The fixed expansion alloy comprises the following components by mass content: 48wt% nickel, 0.65wt% silicon, 0.5wt% cerium, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe; 1. The fixed expansion alloy includes the following components by mass: 48wt% nickel, 0.65wt% silicon, 0.5wt% yttrium, P<0.01wt%, S<0.02wt%, C<0.03wt%, and the balance Fe.
10. Use of the raw material composition of the constant expansion alloy according to any one of claims 1 to 3 or the constant expansion alloy according to any one of claims 7 to 9 in semiconductor vacuum chamber structural parts.