Ni-BASED ALLOY AND MANUFACTURING CONDITION ESTIMATION APPARATUS THEREFOR

Abstract

To provide an apparatus for estimating manufacturing conditions for precipitation-strengthened Ni-based alloys having excellent high-temperature creep ductility, which enables easy estimation of the manufacturing conditions.SOLUTION: An apparatus for estimating manufacturing conditions for Ni-based alloys containing C, Cr, Al, and Ti, comprises: an equilibrium diagram calculation unit configured to calculate the types of precipitates predicted to be formed in the Ni-based alloy and the volume fraction of each precipitate based on the chemical composition using the CALPHAD method; a precipitation kinetics calculation unit configured to calculate the distribution states of M23C6 -type carbides and γ' phases; and a manufacturing condition estimation unit configured to estimate the manufacturing conditions based on the distribution states of the M23C6 -type carbides and the γ' phases and predetermined conditions.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to Ni-based alloys and an apparatus for estimating manufacturing conditions of Ni-based alloys.

Background Art

[0002] As high-temperature members (such as turbine blades) used in thermal power plants and aircraft turbines, Ni-based alloys mainly composed of Ni are often used to satisfy mechanical properties in high-temperature environments.

[0003] In the Ni-based alloy used for high-temperature members, a γ' (gamma prime) phase (L1 2 structure, for example, Ni 3 Al phase) that is lattice-matched with the γ phase is precipitated in the γ (gamma) phase (FCC phase) serving as the matrix to obtain high strength.

[0004] In the turbine parts and the like used, the shape is often complex and there are many uneven and notched parts on the surface, and it is often impossible to say that the member surface is smooth. In that case, for a member with a complex shape or many uneven parts actually used, it is desired that the high-temperature creep life (notched high-temperature creep life) is long when a high-temperature creep rupture test is performed using a notched test piece (notch test piece). In order to extend the notched high-temperature creep life, it is effective to improve the high-temperature creep ductility.

[0005] As a technique for improving ductility at high temperatures, Patent Document 1 discloses a solid-solution strengthened Ni-based superalloy having a composition containing, in mass%, C: 0.01 - 0.15%, Cr: 10 - 25%, Co: 5 - 20%, Mo: 8 - 15%, Al: 0.5 - 2%, Ti: 0.5% or less, B: 0.006% or less, with the balance being Ni and unavoidable impurities, wherein the grain boundary coverage ratio defined by the ratio of the length of the grain boundary covered with carbides to the length of the grain boundary in the alloy is 30% or more, and the undissolved carbides have an average equivalent circle diameter of 0.85 - 0.95 μm and an average number density of 1.8×10 -2 ~2.4×10 -2 pieces / μm 2There is disclosed a Ni-based superalloy characterized in that the elongation at 700 °C is 30% or more and the difference between the elongation at room temperature and the elongation at 700 °C is within 10%.

[0006] Also, as a technique for improving creep ductility at high temperatures, Patent Document 2 discloses a heat treatment method applied to a laminated structure body made of a Ni-based alloy laminated and formed into a predetermined shape. The Ni-based alloy contains, by mass%, Co: 15 to 25%, Cr: 10 to 25%, Mo: 0 to 3.5%, W: 0.5 to 10%, Al: 1.0 to 4.0%, Ti: 0 to 5.0%, Ta: 0 to 4.0%, Nb: 0 to 2.0%, C: 0.03 to 0.2%, B: 0.001 to 0.02%, Zr: 0 to 0.1%, with the balance being Ni and unavoidable impurities. The laminated structure body is heated at a temperature of 1255 °C or higher and 1350 °C or lower for 0.5 hours or more and 100 hours or less according to the content (mass%) of each component element of the Ni-based alloy in a carbide precipitation optimization heat treatment step, and after the carbide precipitation optimization heat treatment step, the laminated structure body is heated at a temperature in the range of 800 to 950 °C for 1 to 30 hours in an aging treatment step. There is disclosed a heat treatment method for a Ni-based alloy laminated structure body characterized by having these steps.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0008]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] However, the technologies of Patent Documents 1 and 2 focus only on the grain boundary carbides of solution-strengthened or precipitation-strengthened Ni-based alloys, and do not focus on the γ' phase, which is the main strengthening phase of precipitation-strengthened Ni-based alloys. Further, in the methods of Patent Documents 1 and 2, heat treatment is performed under various conditions for each chemical composition, and it is necessary to explore appropriate heat treatment conditions, which requires a lot of time and cost for the study.

[0010] The present disclosure has been made to solve the above problems, and an object thereof is to provide a precipitation-strengthened Ni-based alloy excellent in high-temperature creep ductility and an apparatus for estimating manufacturing conditions of a Ni-based alloy capable of easily estimating manufacturing conditions of the Ni-based alloy.

Means for Solving the Problems

[0011] The apparatus for estimating manufacturing conditions of a Ni-based alloy according to the present disclosure is an apparatus for estimating manufacturing conditions of a Ni-based alloy containing C, Cr, Al, and Ti, a phase diagram calculation unit that calculates the types of precipitates predicted to precipitate in the Ni-based alloy and the volume fraction of each precipitate based on the CALPHAD method from the chemical composition of the Ni-based alloy, the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the structural conditions (crystal grain size and dislocation density) of the γ phase serving as a matrix, and the types of precipitates calculated by the phase diagram calculation unit and the input information associated therewith (parameters determined based on the calculation results of the phase diagram calculation unit), and based on the precipitation kinetics theory, MC-type carbides, M 23 C 6 type carbides and the distribution state of the γ' phase in the Ni-based alloy are calculated by a precipitation kinetics calculation unit, and M calculated by the precipitation kinetics calculation unit 23 C 6Distribution state of carbide and γ' phase, M that can be formed from all the contained carbon except carbon in the precipitated MC-type carbide 23 C 6 Target grain boundary M 23 23 C 6 type carbide ratio, target grain boundary γ' phase area which is the target of the area of γ' phase precipitated on the grain boundary per 1μm, and based on the target fine grain interior γ' phase area ratio which is the target of the area ratio of γ' phase with an equivalent circle diameter of less than 20nm in the grain interior to the total area of the grain, a manufacturing condition estimating unit that estimates manufacturing conditions, and is provided with.

[0012] The Ni-based alloy of the present disclosure has a chemical composition in mass%, C: 0.02 to 0.06%, Si: 0.15% or less, Mn: 0.15% or less, P: 0.01% or less, S: 0.005% or less, Cu: 0.1% or less, Cr: 18 to 20%, Mo: 5.5 to 7.0%, W: 0.8 to 1.2%, Co: 11 to 14%, Al: 1.8 to 2.3%, Ti: 2.90 to 3.25%, Fe: 2% or less, B: 0.004 to 0.010% is contained, the balance consists of Ni and unavoidable impurities, and M 23 23 C 6 type carbide of which the ratio precipitated at the grain boundary is 70% or more, the area of γ' phase precipitated on the grain boundary per 1μm is 0.19μm 2 2 or less, The area ratio of γ' phase with an equivalent circle diameter of less than 20nm in the grain interior to the total area of the grain is 0.1% or less.

Advantages of the Invention

[0013] According to each of the above aspects of the present disclosure, it is possible to provide a precipitation-strengthened Ni-based alloy excellent in high-temperature creep ductility and a manufacturing condition estimating device for a Ni-based alloy capable of easily estimating manufacturing conditions of the Ni-based alloy.

Brief Description of the Drawings

[0014]

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Embodiments for Carrying Out the Invention

[0015] <First Embodiment> As a result of intensive studies by the present inventors, the proportion of M-type carbides that can be generated from all the contained carbon except carbon in the precipitated MC-type carbide and that precipitate at grain boundaries is 70% or more, and the area of the γ'-phase precipitated at grain boundaries per 1 μm is 0.19 μm 23 C 6 type carbide, and the area of the γ'-phase precipitated at grain boundaries per 1 μm is 0.19 μm 2The following is known: By setting the area ratio of the γ' phase with an equivalent circle diameter of less than 20 nm in the crystal grains to 0.1% or less with respect to the total area of the crystal grains, the high-temperature creep ductility is improved. In this specification, the Ni-based alloy is, for example, an alloy containing 48 mass% or more of Ni and containing one or more elements selected from the group consisting of Cr, W, Al, Ta, Co, Mo, Ti, C, and B. The Ni-based alloy of this specification has a γ' (gamma prime) phase (L1 2 structure, for example, Ni 3 Al phase) precipitated in the γ (gamma) phase (FCC phase) which is the matrix, and is a precipitation-strengthened Ni-based alloy. Here, the crystal grains are the γ phase. In this specification, the numerical range represented by "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. In this specification, the temperature such as the holding temperature is the temperature of the surface of the Ni-based alloy.

[0016] The chemical composition of the Ni-based alloy of the present disclosure is such that the proportion of M 23 C 6 type carbides precipitated at the grain boundaries among all the contained carbons excluding carbon in the precipitated MC type carbides is 70% or more, and the area of the γ' phase precipitated at the grain boundaries per 1 μm is 0.19 μm 2 or less, and if the area ratio of the γ' phase with an equivalent circle diameter of less than 20 nm in the crystal grains to the total area of the crystal grains can be 0.1% or less, it is not particularly limited. Such a chemical composition of the Ni-based alloy is, for example, in mass%, C: 0.02 to 0.06%, Si: 0.15% or less, Mn: 0.15% or less, P: 0.01% or less, S: 0.005% or less, Cu: 0.1% or less, Cr: 18 to 20%, Mo: 5.5 to 7.0%, W: 0.8 to 1.2%, Co: 11 to 14%, Al: 1.8 to 2.3%, Ti: 2.90 to 3.25%, Fe: 2% or less, B: 0.004 to 0.010% and has a chemical composition consisting of the balance being Ni and unavoidable impurities. In the following description, "%" regarding the content means "mass%".

[0017] "C: 0.02 to 0.06%" C is M23 C 6 is an element that forms carbides typified by carbide of the M 23 C 6 type. By appropriately heat-treating, especially precipitating M 23 C 6 type carbide at the grain boundaries, grain boundary strengthening and notch strengthening can be achieved. If the C content is less than 0.02%, the amount of carbide becomes too small to expect the strengthening effect. On the other hand, if C is more than 0.06%, the amount of MC type carbide precipitating in the grains increases, and the strength within the grains becomes too large compared to the grain boundary strength, resulting in notch weakening. Therefore, the C content is set to 0.02 - 0.06%. A more preferable C content is 0.03 or more. A more preferable C content is 0.05% or less.

[0018] "Si: 0.15% or less" Si is an element having a deoxidizing effect. However, if added in excess, it causes an increase in inclusions, so the upper limit of the Si content is set to 0.15%. To obtain the above-mentioned deoxidizing effect, the lower limit of Si may be set to 0.01%.

[0019] "Mn: 0.15% or less" Mn is an element having a deoxidizing effect. However, if added in excess, it easily forms MnS, so the upper limit of the Mn content is set to 0.15%. To obtain the above-mentioned deoxidizing effect, the lower limit of Mn may be set to 0.01%.

[0020] "P: 0.01% or less" P is an element harmful to high-temperature creep ductility, and it is preferably reduced as much as possible. Therefore, the P content is set to 0.01% or less. The P content may also be 0.0001% or more.

[0021] "S: 0.005% or less" S is an element harmful to high-temperature creep ductility, and it is preferably reduced as much as possible. Therefore, the S content is set to 0.005% or less. The S content may also be 0.0001% or more.

[0022] "Cu: 0.1% or less" ​​​​Cu is an element that exists as an impurity. When the Cu content exceeds 0.1%, the corrosion resistance of the Ni-based alloy decreases. Therefore, the Cu content should be 0.1% or less.

[0023] "Cr: 18 - 20%" Cr is an element effective for improving oxidation resistance at high temperatures. However, if it is less than 18%, the improvement in high-temperature oxidation resistance by the addition of Cr may not be sufficient. Also, Cr is a constituent element of M 23 C 6 type carbides. But if the Cr content is less than 18%, the precipitation amount of M 23 C 6 type carbides becomes small, and it becomes difficult to extend the notch high-temperature creep life. On the other hand, if the Cr content exceeds 20%, it causes the precipitation of harmful phases, leading to a decrease in strength and ductility, which is not preferable. Therefore, the Cr content should be in the range of 18 - 20%.

[0024] "Mo: 5.5 - 7.0%" Mo is an element that dissolves in the γ-phase, which is the matrix, and is effective for improving strength by solid solution strengthening. To obtain the above effects, the Mo content should be 5.5% or more. If the Mo content is more than 7.0%, harmful phases precipitate, causing a decrease in strength and ductility. Therefore, the Mo content should be in the range of 5.5 - 7.0%.

[0025] "W: 0.8 - 1.2%" W is an element that dissolves in the γ-phase, which is the matrix, and is effective for improving strength by solid solution strengthening. Also, W is a constituent element of M 23 C 6 type carbides. But since it is an element with slow diffusion, it has the effect of suppressing the coarsening of M 23 C 6 type carbides. To exert these effects, the addition of 0.8% or more of W is necessary. If the W content is more than 1.2%, harmful phases may precipitate, causing a decrease in strength and ductility. Therefore, the W content should be in the range of 0.8 - 1.2%.

[0026] "Co: 11 - 14%" Co is an element that has the effect of increasing the limit (solubility limit) for dissolving elements such as Ti and Al in the matrix at high temperatures. Therefore, not only does it bring about the effect of improving the matrix strength by finely dispersing and precipitating the γ' phase through solution treatment - aging treatment, but it also has the effect of promoting the solution of MC - type carbides during carbide precipitation optimization heat treatment. Among these effects, in order to obtain the latter effect in particular, 11% or more of Co is required. On the other hand, if Co is more than 14%, harmful phases will precipitate and embrittle, resulting in a decrease in high - temperature strength. Therefore, the Co content is within the range of 11 - 14%.

[0027] "Al: 1.8 - 2.3%" Al is an element that forms the γ' phase. It enhances the high - temperature strength of the alloy, especially the high - temperature creep strength, through precipitation strengthening by γ' phase precipitation particles, and is also effective in improving oxidation resistance and corrosion resistance at high temperatures. If the Al content is less than 1.8%, the precipitation amount of the γ' phase decreases, and precipitation strengthening by the precipitates cannot be achieved sufficiently. However, if the Al content exceeds 2.3%, there is a risk of a decrease in high - temperature creep ductility. Therefore, the Al content is within the range of 1.8 - 2.3%.

[0028] "Ti: 2.90 - 3.25%" Ti is an element that forms the γ' phase. It enhances the high - temperature strength of the alloy, especially the high - temperature creep strength, through precipitation strengthening by γ' phase precipitation particles, and is also effective in improving oxidation resistance and corrosion resistance at high temperatures. To obtain the above - mentioned effects, the Ti content should be 2.90% or more. If the Ti content exceeds 3.25%, the precipitation amount of MC - type carbides increases, carbon is fixed, and even if carbide precipitation optimization heat treatment is carried out, the precipitation amount of M 23 C 6 type carbides at the grain boundaries may decrease. Therefore, the Ti content is set to 3.25% or less.

[0029] "Fe: 2% or less" Fe is an element that, even when contained in trace amounts in a Ni-based alloy, has the effect of improving its hot workability. However, if the Fe content becomes excessive, the strength decreases. Therefore, the Fe content is set to 2% or less. The Fe content may be 0.1% or more.

[0030] "B: 0.004 to 0.010%" B is an element that, by existing at the grain boundaries, strengthens the grain boundaries and is effective in improving high-temperature creep strength and notch weakening. To obtain the above effects, the B content is set to 0.004% or more. However, if the B content exceeds 0.010%, there is a risk of generating borides and reducing ductility. Therefore, the B content is in the range of 0.004 to 0.010%.

[0031] "The balance" The balance of the Ni-based alloy of the present disclosure is Ni and unavoidable impurities. Here, unavoidable impurities are components that are mixed in during the raw materials and manufacturing process when manufacturing the Ni-based alloy. The content of unavoidable impurities is allowed within the range where the effects of the Ni-based alloy of the present disclosure can be obtained.

[0032] "Ratio of grain boundary M" 23 C 6 type carbide In the Ni-based alloy of the present disclosure, from all the contained carbon that can be generated from all the contained carbon excluding carbon in the precipitated MC-type carbide, the ratio of M 23 C 6 type carbide that precipitates at the grain boundaries (grain boundary M 23 C 6 type carbide ratio) is 70% or more. M in the MC-type carbide and M 23 C 6 type carbide is a metal element, and C is a carbon element. Examples of the MC-type carbide include TiC and TaC. M 23 C 6 type carbide includes, for example, (Cr, Mo, W) 23 C 6 is. The ratio of grain boundary M 23 C 6 type carbide has an upper limit of 100%. The ratio of grain boundary M 23 C 6By making the proportion of type carbides 70% or more, preferential recovery of dislocations and subgrain formation in the vicinity of grain boundaries are suppressed, local deformation in the vicinity of grain boundaries at high temperatures is less likely to occur, and ductility is improved.

[0033] Grain boundary M 23 C 6 The proportion of M-type carbides can be measured by the following method. A Ni-based alloy is cut out, and the cross section is polished to prepare a specimen for observation. The specimen is observed using a field emission scanning electron microscope (FE-SEM) and the M 23 C 6 It is confirmed in advance that the type carbides are precipitated only at the grain boundaries. The Ni-based alloy is cut out, electrolyzed in an electrolyte, and filtered to recover the residue. The residue is decomposed with acid, and the amount of elements in the residue is measured by inductively coupled plasma atomic emission spectrometry. In addition, X-ray diffraction measurement is performed on the residue to identify the precipitated phase. The proportion of the constituent elements of the identified precipitated phase is calculated using an equilibrium phase diagram. From these, the grain boundary M contained in the residue is determined. 23 C 6 On the other hand, the amount of M carbides that can be generated from all the carbon contained except for the carbon in the crystallized MC carbides can be calculated. 23 C 6 The maximum amount of carbides is determined by equilibrium phase diagram calculations and the Scheil-Gulliver calculation described later. 23 C 6 The amount of M type carbides that can be produced from all the carbon contained except for the carbon in the crystallized MC type carbides is 23 C 6 By dividing it by the maximum amount of type carbides, the grain boundary M 23 C 6 The proportion of type carbides can be determined.

[0034] "Area of ​​γ' phase precipitated at grain boundaries per 1μm" In the Ni-based alloy of the present disclosure, the area of ​​the γ' phase precipitated at the grain boundaries per μm (grain boundary γ' phase area) is 0.19 μm 2 The lower limit of the grain boundary γ' phase area is 0 μm 2By suppressing the precipitation of the γ'-phase at the grain boundaries to a certain level or below, the hierarchical grain boundary structure in which the γ'-phase and carbides are intricately intertwined is relaxed, making it less likely for grain boundary cracks to occur and improving ductility.

[0035] The area of the γ'-phase at the grain boundaries can be measured by the following method. Cut out a Ni-based alloy, polish the cross-section, and prepare a sample for observation. Observe using a field emission scanning electron microscope (FE-SEM), and for each observation sample, take 3 images at a magnification of 10,000 times (1 field area: 90 μm 2 ) and consider the white regions on the grain boundaries within each field of view (the white regions on the grain boundaries in Fig. 1) as the γ'-phase precipitated at the grain boundaries. Measure the area of the γ'-phase precipitated at the grain boundaries and the length of the grain boundaries within each field of view using image analysis software. By dividing the total area of the γ'-phase precipitated at the obtained grain boundaries by the total length of the grain boundaries, the area of the γ'-phase precipitated per 1 μm of the grain boundaries can be determined.

[0036] "The area ratio of the γ'-phase with an equivalent circle diameter of less than 20 nm within the grains to the total area of the grains" In the Ni-based alloy of the present disclosure, the area ratio (intra-grain fine γ'-phase area ratio) of the γ'-phase with an equivalent circle diameter of less than 20 nm within the grains to the total area of the grains is 0.1% or less. Here, the equivalent circle diameter of the γ'-phase refers to the diameter of a perfect circle having an area equal to the area of the γ'-phase. By preventing the precipitation of fine γ'-phase within the grains during use, excessive retardation of intra-grain deformation can be prevented, and ductility can be improved. The lower limit of the intra-grain fine γ'-phase area ratio is 0%. It is preferable that the intra-grain fine γ'-phase area ratio after the final aging treatment is 0.1% or less.

[0037] The intra-grain fine γ'-phase area ratio can be measured by the following method. Cut out a Ni-based alloy, polish the cross-section, and prepare a sample for observation. Observe using a field emission scanning electron microscope (FE-SEM), and for each sample, take 3 images at a magnification of 30,000 times (1 field area: 10 μm 2Photograph with and define the fine γ' phase precipitated within the crystal grains in each field of view and having a white region with an equivalent circle diameter of less than 20 nm within the crystal grains. Measure the area of the fine γ' phase precipitated within the crystal grains in each field of view and the area of the crystal grains using image analysis software. The area fraction of the fine γ' phase within the crystal grains can be obtained by dividing the total area of the fine γ' phase with an equivalent circle diameter of less than 20 nm precipitated within the grains of all the measured crystal grains by the total area of the crystal grains.

[0038] Next, a method for manufacturing the Ni-based alloy of the present disclosure will be described. FIG. 2 is a flowchart of a method for manufacturing a Ni-based alloy according to the first embodiment of the present disclosure. The method for manufacturing the Ni-based alloy of the present disclosure includes a solution treatment step S1 of performing a solution treatment for dissolving the γ' phase on a Ni-based alloy raw material, and after the solution treatment step S1, γ' phase and M 23 C 6 A primary aging treatment step S2 of performing an aging treatment for precipitating type carbide within the crystal grains and at the grain boundaries, and a final aging treatment step S3 of performing an aging treatment for suppressing the precipitation of fine γ' phase with an equivalent circle diameter of less than 20 nm.

[0039] (Solution treatment step S1) In the solution treatment step S1, by performing a heat treatment on the Ni-based alloy raw material at a temperature equal to or higher than the solution temperature Ts of the γ' phase and lower than the melting point Tm of the γ phase, the elements forming the γ' phase are dissolved in the matrix. The solution temperature Ts of the γ' phase and the melting point Tm of the γ phase can be obtained, for example, by calculation using thermodynamic calculation software (for example, JMatPro manufactured by Sente Software) based on the chemical composition. The temperature conditions of the solution treatment are not particularly limited as long as the elements forming the γ' phase can be dissolved. The solution treatment conditions are, for example, conditions of heating at a temperature in the range of 1100 to 1140 °C for 1 to 10 hours. The Ni-based alloy raw material is a casting of a Ni-based alloy having the above-described chemical composition, or a material obtained by rolling or forging the casting.

[0040] The Ni-based alloy raw material may be produced, for example, by performing a melting treatment, a forging treatment, or a rolling treatment. Known conditions can be used for the conditions of each treatment.

[0041] (Primary aging treatment process S2) In the primary aging treatment process S2, after the solution treatment process S1, aging treatment is performed on the Ni-based alloy raw material after solution treatment to precipitate γ' phase and M 23 C 6 type carbides in the crystal grains and at the grain boundaries. This aging treatment promotes the precipitation of the γ' phase to increase the strength of the matrix, and at the same time, M 23 C 6 type carbides are precipitated on the grain boundaries to increase the grain boundary strength, improve the high-temperature creep ductility, and impart creep notch strengthening characteristics. The temperature conditions for this aging treatment are those estimated by the Ni-based alloy manufacturing condition estimation device described later. The temperature conditions for the primary aging treatment are, for example, heating at a temperature in the range of 810 to 860 °C for 20 to 100 hours.

[0042] (Final aging treatment process S3) In the final aging treatment process S3, in order to suppress the precipitation of fine γ' phase during use in a high-temperature environment, aging treatment is performed on the Ni-based alloy raw material after the primary aging treatment process S2. Thereby, the Ni-based alloy of the present disclosure can be obtained. The temperature conditions for this final aging treatment are those estimated by the Ni-based alloy manufacturing condition estimation device described later. The temperature conditions for the final aging treatment are, for example, heating at a temperature in the range of 740 to 780 °C for 4 to 50 hours.

[0043] In the Ni-based alloy of the present disclosure, the manufacturing conditions are estimated by the Ni-based alloy manufacturing condition estimation device according to the chemical composition. Next, the Ni-based alloy manufacturing condition estimation device used for estimating the manufacturing conditions will be described.

[0044] (Ni-based alloy manufacturing condition estimation device) FIG. 3 is a block diagram showing the configuration of an apparatus for estimating production conditions of a Ni-based alloy according to the first embodiment of the present disclosure. The apparatus 100 for estimating production conditions of a Ni-based alloy is an apparatus for estimating production conditions of a Ni-based alloy containing C, Cr, Al, and Ti. Based on the CALPHAD method from the chemical composition of the Ni-based alloy, an equilibrium diagram calculation unit 21 calculates the types of precipitates predicted to precipitate in the Ni-based alloy and the volume fraction of each precipitate. From the chemical composition of the Ni-based alloy, the production conditions of the Ni-based alloy, the structural conditions (crystal grain size and dislocation density) of the γ-phase serving as a matrix, the types of precipitates calculated by the equilibrium diagram calculation unit 21, and the accompanying input information (parameters determined based on the calculation results of the equilibrium diagram calculation unit 21), based on the precipitation kinetics theory, the MC-type carbide, M 23 C 6 type carbide and the distribution state of the γ' phase in the Ni-based alloy are calculated by a precipitation kinetics calculation unit 22. From the distribution state of the M 23 C 6 type carbide and the γ' phase calculated by the precipitation kinetics calculation unit 22, all the carbon contained in the MC-type carbide excluding carbon, the target ratio of the M 23 C 6 type carbide that precipitates at the grain boundaries, which is the target ratio of the grain boundary M 23 C 6Based on the ratio of carbide types, the target grain boundary γ'-phase area which is the target area of the γ'-phase precipitating on the grain boundary per 1 μm, and the target fine grain interior γ'-phase area ratio which is the target area ratio of the γ'-phase with an equivalent circle diameter of less than 20 nm in the grain interior to the total area of the grains, a manufacturing condition estimation unit 30 for estimating manufacturing conditions is provided. The manufacturing condition estimation apparatus 100 for Ni-based alloy further includes an input unit 10 for acquiring input information and an output unit 40 for outputting the estimated manufacturing conditions of the Ni-based alloy. By determining the types of precipitates from the calculation of the equilibrium phase diagram calculation unit 21, the precipitates to be considered as the calculation target in the subsequent precipitation rate theory calculation unit 22 are determined. Here, the input information (parameters determined based on the calculation results of the equilibrium phase diagram calculation unit 21) associated with the types of the above-mentioned precipitates refers to various parameters (parameters associated with each precipitate) associated with the precipitates determined as the calculation target. Specifically, it refers to the nucleation sites of each precipitate (in the grain interior or at the grain boundary), the interfacial energy of the precipitate, the aspect ratio of the precipitate, and the lattice misfit strain of the precipitate (in the case of a precipitate where the matrix and the crystal lattice are in agreement).

[0045] (Input unit 10) The input unit 10 acquires input information used in the calculations of the equilibrium phase diagram calculation unit 21, the precipitation rate theory calculation unit 22, and the Scheil-Gulliver calculation unit 23 described later. The input information includes the chemical composition of the Ni-based alloy, manufacturing conditions (heat treatment history based on the manufacturing conditions), the microstructure conditions of the γ-phase serving as the matrix, the type of precipitate, the nucleation site of the precipitate (within the crystal grains or at the grain boundaries), the interfacial energy of the precipitate, the aspect ratio of the precipitate, and the lattice misfit strain of the precipitate (in the case of a precipitate whose crystal lattice is in agreement with the matrix). The microstructure conditions of the γ-phase serving as the matrix are, for example, the crystal grain size and dislocation density of the γ-phase. The method for acquiring the input information is not particularly limited. It may be input manually from publicly known information, or it may be acquired from a database stored in a storage unit (not shown). The chemical composition of the Ni-based alloy is sent to the equilibrium phase diagram calculation unit 21, and based on the calculation results of the equilibrium phase diagram calculation unit 21, the chemical composition of the Ni-based alloy, manufacturing conditions (heat treatment history based on the manufacturing conditions), the microstructure conditions of the γ-phase serving as the matrix (crystal grain size and dislocation density), the type of precipitate, the nucleation site of the precipitate (within the crystal grains or at the grain boundaries), the interfacial energy of the precipitate, the aspect ratio of the precipitate, and the lattice misfit strain of the precipitate (in the case of a precipitate whose crystal lattice is in agreement with the matrix) are sent to the precipitation rate theory calculation unit 22.

[0046] (Equilibrium Phase Diagram Calculation Unit 21) The equilibrium phase diagram calculation unit 21 calculates, based on the CALPHAD method, the types of precipitates predicted to precipitate in the Ni-based alloy and the volume fraction of each precipitate from the chemical composition of the Ni-based alloy sent from the input unit 10. Here, the precipitate is a secondary phase generated from the solid-phase matrix that is a supersaturated solid solution during the heat treatment process. CALPHAD is an abbreviation for CALculation of PHAse Diagrams, and calculates the phase diagram from the Gibbs energy representing the thermodynamic properties of the alloy. The calculation by CALPHAD can be performed, for example, as described in Non-Patent Document 1. By the CALPHAD method, the equilibrium state reached at each temperature can be calculated, and as a result of the thermodynamic calculation, for example, the types of compounds (precipitates) contained in the equilibrium state at each temperature and the volume fraction of the compounds (precipitates). Based on the types and volume fractions of the precipitates at each temperature calculated by the equilibrium phase diagram calculation unit 21, the types of precipitates sent from the input unit 10 to the precipitation rate theory calculation unit 22 and the accompanying input information (nucleation sites of the precipitates (within the crystal grains or at the grain boundaries), the interfacial energy of the precipitates, the aspect ratio of the precipitates, the lattice misfit strain of the precipitates (in the case of precipitates where the matrix and the crystal lattice are in agreement)) are determined.

[0047] (Precipitation rate theory calculation unit 22) The precipitation rate theory calculation unit 22 calculates the distribution states of MC-type carbides, M 23 C 6 -type carbides and γ'-phase in the Ni-based alloy based on the precipitation rate theory from the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the microstructural conditions (crystal grain size and dislocation density) of the γ-phase serving as the matrix, and the types of precipitates and the accompanying input information (parameters determined based on the calculation results of the equilibrium phase diagram calculation unit 21). Specifically, the precipitation rate theory calculation unit 22 calculates MC-type carbides, M23 C 6 Calculate the distribution states of MC-type carbides and γ'-phase. The calculation based on the precipitation rate theory (precipitation rate theory calculation) can be performed, for example, based on the method described in Non-Patent Document 1. The precipitation rate theory calculation may be performed using MatCalc 6 manufactured by MatCalc Engineering Co., Ltd. M 23 C 6 The distribution states of MC-type carbides and γ'-phase include the position and area of the γ'-phase and M 23 C 6 The position and area of MC-type carbides. The precipitation rate theory calculation unit 22 sends the calculated distribution states of MC-type carbides and γ'-phase to the manufacturing condition estimation unit 30. The manufacturing conditions used in the calculation by the precipitation rate theory calculation unit 22 are the initial manufacturing conditions sent from the input unit 10 or the manufacturing conditions after being changed by the manufacturing condition estimation unit 30. 23 C 6 The distribution states of MC-type carbides and γ'-phase are sent to the manufacturing condition estimation unit 30. The manufacturing conditions used in the calculation by the precipitation rate theory calculation unit 22 are the initial manufacturing conditions sent from the input unit 10 or the manufacturing conditions after being changed by the manufacturing condition estimation unit 30.

[0048] (Manufacturing condition estimation unit 30) The manufacturing condition estimation unit 30 estimates the manufacturing conditions of the Ni-based alloy based on the distribution states of MC-type carbides and γ'-phase calculated by the precipitation rate theory calculation unit 22 and the target grain boundary MC 23 C 6 type carbide ratio, the target grain boundary γ'-phase area, and the target fine γ'-phase area ratio in the target grain interior. The manufacturing conditions estimated here are, for example, the holding temperature of the aging treatment in the primary aging treatment step S2, the holding time of the aging treatment in the primary aging treatment step S2, the holding temperature of the aging treatment in the final aging treatment step S3, and the holding time of the aging treatment in the final aging treatment step S3. The target grain boundary MC 23 C 6 type carbide ratio is the target ratio of the MC-type carbides that precipitate at the grain boundaries among all the contained carbons excluding carbon in the precipitated MC-type carbides. The target grain boundary γ'-phase area is the target area of the γ'-phase that precipitates at the grain boundaries per 1 μm. The target fine γ'-phase area ratio in the target grain interior is the target area ratio of the γ'-phase with an equivalent circle diameter of less than 20 nm in the grain interior to the total area of the grains. 23 C 6 The type carbide ratio is the target ratio of the MC-type carbides that precipitate at the grain boundaries among all the contained carbons excluding carbon in the precipitated MC-type carbides. The target grain boundary γ'-phase area is the target area of the γ'-phase that precipitates at the grain boundaries per 1 μm. The target fine γ'-phase area ratio in the target grain interior is the target area ratio of the γ'-phase with an equivalent circle diameter of less than 20 nm in the grain interior to the total area of the grains. 23 C 6 The type carbide ratio is the target ratio of the MC-type carbides that precipitate at the grain boundaries among all the contained carbons excluding carbon in the precipitated MC-type carbides. The target grain boundary γ'-phase area is the target area of the γ'-phase that precipitates at the grain boundaries per 1 μm. The target fine γ'-phase area ratio in the target grain interior is the target area ratio of the γ'-phase with an equivalent circle diameter of less than 20 nm in the grain interior to the total area of the grains.

[0049] Target grain boundary M 23 C 6 The proportion of type carbide is appropriately set according to the required properties. If it is to improve high-temperature creep ductility, the target grain boundary M 23 C 6 The proportion of type carbide is preferably 70% or more. For the target grain boundary M 23 C 6 By setting the proportion of type carbide to 70% or more, the preferential recovery of dislocations and subgrain formation near the grain boundary are suppressed, local deformation near the grain boundary at high temperature is less likely to occur, and high-temperature creep ductility can be improved.

[0050] The target grain boundary γ'-phase area is appropriately set according to the required properties. If it is to improve high-temperature creep ductility, the target grain boundary γ'-phase area is preferably 0.19 μm or less per grain boundary per 1 μm. 2 For the target grain boundary γ'-phase area, by setting it to 0.19 μm or less per grain boundary per 1 μm, the hierarchical grain boundary structure in which the γ'-phase and carbide are intricately intertwined is relaxed, grain boundary cracks are less likely to occur, and high-temperature creep ductility can be improved. 2 By setting it to 0.19 μm or less per grain boundary per 1 μm, the hierarchical grain boundary structure in which the γ'-phase and carbide are intricately intertwined is relaxed, grain boundary cracks are less likely to occur, and high-temperature creep ductility can be improved.

[0051] The target fine γ'-phase area ratio within the grain is appropriately set according to the required properties. If it is to improve high-temperature creep ductility, the target fine γ'-phase area ratio within the grain is preferably 0.1% or less. By preventing the precipitation of fine γ'-phase within the grain during service, excessive retardation of intragranular deformation is prevented, and high-temperature creep ductility can be improved.

[0052] When the distribution state of the type carbide and γ'-phase calculated by the precipitation rate theory calculation unit 22 does not satisfy the target grain boundary M 23 C 6 type carbide ratio, the target grain boundary γ'-phase area, and the target fine γ'-phase area ratio within the grain, the manufacturing conditions of the Ni-based alloy are changed, and the changed manufacturing conditions are sent to the precipitation rate theory calculation unit 22. The manufacturing condition estimation unit 30 is for M calculated by the precipitation rate theory calculation unit 22 23 C 6 When the distribution state of the type carbide and γ'-phase calculated by the precipitation rate theory calculation unit 22 does not satisfy the target grain boundary M 23 C6 The distribution state of the carbide of type M and the γ' phase is the target grain boundary M 23 C 6 When the ratio of the carbide of type M, the area of the γ' phase at the target grain boundary, and the area ratio of the fine γ' phase in the target grain interior are satisfied, the manufacturing conditions used in the calculation by the precipitation rate calculation unit 22 are sent to the output unit 40.

[0053] First, for the grain boundary M 23 C 6 When the distribution state of the carbide of type M does not satisfy the ratio of the carbide of type M at the target grain boundary 23 C 6 A method for adjusting the manufacturing conditions when the distribution state of the carbide of type M does not satisfy the ratio of the carbide of type M at the target grain boundary will be described. FIG. 4 is a diagram for explaining a method for determining the appropriate aging treatment conditions based on the amount of carbide of type M generated at the grain boundary. The horizontal axis in FIG. 4 represents the holding time of the primary aging treatment. The vertical axis represents the volume fraction of the carbide of type M calculated by the precipitation rate calculation unit 22 at the grain boundary. The holding temperature of the primary aging treatment has two conditions (temperature 1 > temperature 2). As shown in FIG. 4, the higher the temperature, the greater the rate of increase in the volume fraction of the carbide of type M. Also, in both cases, the longer the holding time of the primary aging treatment, the more the carbide of type M monotonically increases, and from midway, the amount of carbide of type M generated saturates. When the distribution state of the carbide of type M at the grain boundary does not satisfy the ratio of the carbide of type M at the target grain boundary 23 C 6 A method for determining the appropriate aging treatment conditions based on the amount of carbide of type M generated at the grain boundary will be described. FIG. 4 is a diagram for explaining a method for determining the appropriate aging treatment conditions based on the amount of carbide of type M generated at the grain boundary. The horizontal axis in FIG. 4 represents the holding time of the primary aging treatment. The vertical axis represents the volume fraction of the carbide of type M calculated by the precipitation rate calculation unit 22 at the grain boundary. The holding temperature of the primary aging treatment has two conditions (temperature 1 > temperature 2). As shown in FIG. 4, the higher the temperature, the greater the rate of increase in the volume fraction of the carbide of type M. Also, in both cases, the longer the holding time of the primary aging treatment, the more the carbide of type M monotonically increases, and from midway, the amount of carbide of type M generated saturates. When the distribution state of the carbide of type M at the grain boundary does not satisfy the ratio of the carbide of type M at the target grain boundary 23 C 6 type M carbide volume fraction. The holding temperature of the primary aging treatment has two conditions (temperature 1 > temperature 2). As shown in FIG. 4, the higher the temperature, the greater the rate of increase in the volume fraction of the carbide of type M. Also, in both cases, the longer the holding time of the primary aging treatment, the more the carbide of type M monotonically increases, and from midway, the amount of carbide of type M generated saturates. When the distribution state of the carbide of type M at the grain boundary does not satisfy the ratio of the carbide of type M at the target grain boundary 23 C 6 type M carbide volume fraction. The holding temperature of the primary aging treatment has two conditions (temperature 1 > temperature 2). As shown in FIG. 4, the higher the temperature, the greater the rate of increase in the volume fraction of the carbide of type M. Also, in both cases, the longer the holding time of the primary aging treatment, the more the carbide of type M monotonically increases, and from midway, the amount of carbide of type M generated saturates. When the distribution state of the carbide of type M at the grain boundary does not satisfy the ratio of the carbide of type M at the target grain boundary 23 C 6 type M carbide, and from midway, the amount of carbide of type M generated saturates. At the grain boundary M 23 C 6 type M carbide, and from midway, the amount of carbide of type M generated saturates. At the grain boundary M 23 C 6 When the distribution state of the carbide of type M is the target grain boundary M 23 C 6 When the ratio of the carbide of type M is not satisfied, the manufacturing condition estimation unit 30, for example, increases the holding time of the primary aging treatment or raises the holding temperature of the primary aging treatment, and sends the changed conditions of the primary aging treatment to the precipitation rate calculation unit 22.

[0054] Next, a method for adjusting manufacturing conditions when the distribution state of the grain boundary γ'-phase does not meet the target grain boundary γ'-phase area will be described. FIG. 5 is a diagram for explaining a method for determining appropriate aging treatment conditions based on the amount of the grain boundary γ'-phase generated. The horizontal axis in FIG. 5 represents the holding temperature of the primary aging treatment. The vertical axis indicates the volume fraction of the grain boundary γ'-phase calculated by the precipitation rate calculation unit 22. The holding time of the primary aging treatment has two conditions (holding time 1 < holding time 2). As shown in FIG. 5, when the holding temperature is the same, the volume fraction of the grain boundary γ'-phase increases as the holding time becomes longer. Also, when the holding time is the same, the volume fraction of the grain boundary γ'-phase increases as the holding temperature becomes higher. When the distribution state of the grain boundary γ'-phase does not meet the target grain boundary γ'-phase area, the manufacturing condition estimation unit 30, for example, shortens the holding time of the primary aging treatment or lowers the holding temperature, and sends the changed primary aging treatment conditions to the precipitation rate calculation unit 22.

[0055] Next, a method for adjusting manufacturing conditions when the distribution state of the fine γ'-phase in the grains does not meet the target fine γ'-phase area ratio in the grains will be described. FIG. 6 is a diagram for explaining a method for determining appropriate final aging treatment conditions based on the presence or absence of precipitation of the fine γ'-phase in the grains. The horizontal axis in FIG. 6 represents the holding temperature of the final aging treatment. The vertical axis represents the holding time of the final aging treatment. The white circles in FIG. 6 indicate that the distribution state of the fine γ'-phase in the grains calculated by the precipitation rate calculation unit 22 meets the target fine γ'-phase area ratio in the grains. The × in FIG. 6 indicates that the distribution state of the fine γ'-phase in the grains calculated by the precipitation rate calculation unit 22 does not meet the target fine γ'-phase area ratio in the grains. As shown in FIG. 6, it can be seen that no fine γ'-phase precipitates in the case of holding temperature and holding time within a predetermined range. When the distribution state of the fine γ'-phase in the grains does not meet the target fine γ'-phase area ratio in the grains, the manufacturing condition estimation unit 30, for example, changes the holding temperature and holding time of the final aging treatment at predetermined intervals, and sends the changed final aging treatment conditions to the precipitation rate calculation unit 22.

[0056] (Output unit 40) The output unit 40 is a display device such as a liquid crystal display, for example. The output unit 40 displays the manufacturing conditions sent from the manufacturing condition estimation unit 30.

[0057] Next, a method for estimating the manufacturing conditions of a Ni-based alloy using the Ni-based alloy manufacturing condition estimation apparatus 100 of the present disclosure will be described.

[0058] FIG. 7 is a flowchart of a method for estimating the manufacturing conditions of a Ni-based alloy according to the first embodiment of the present disclosure. In the Ni-based alloy manufacturing condition estimation apparatus 100, when the manufacturing condition estimation process starts, the input unit 10 acquires the above-described input information such as the chemical composition and manufacturing conditions of the Ni-based alloy from a storage unit (not shown), and sends the acquired input information to the equilibrium phase diagram calculation unit 21 (step S11). The input information may be input manually.

[0059] The equilibrium phase diagram calculation unit 21 that has received the input information calculates the types of precipitates predicted to precipitate in the Ni-based alloy and the volume fraction of each precipitate based on the CALPHAD method from the chemical composition of the Ni-based alloy sent from the input unit 10. Next, the equilibrium phase diagram calculation unit 21 determines the types of precipitates and the input information associated therewith (nucleation sites of precipitates (inside or at the grain boundaries of grains), interface energy of precipitates, aspect ratio of precipitates, lattice misfit strain of precipitates (in the case of precipitates whose crystal lattice is matched with the matrix)) sent from the input unit 10 to the precipitate growth rate calculation unit 22 based on the types and volume fractions of precipitates at each temperature calculated by the equilibrium phase diagram calculation unit 21 (step S12). The types and volume fractions of precipitates to be calculated are the types and volume fractions of precipitates at each temperature in a predetermined temperature range. The predetermined temperature range is the temperature range of the assumed manufacturing conditions (thermal history).

[0060] The precipitation rate theory calculation unit 22 that receives the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the tissue conditions (crystal grain size and dislocation density) of the γ-phase serving as the matrix, and the types of calculated precipitates and the accompanying input information (parameters determined based on the calculation results of the equilibrium phase diagram calculation unit 21) calculates, based on the precipitation rate theory, the distribution states of MC-type carbides, M 23 C 6 -type carbides, and γ'-phase in the Ni-based alloy, and sends the calculated distribution states of M 23 C 6 -type carbides and γ'-phase to the manufacturing condition estimation unit 30. (Step S14). The manufacturing conditions used in the calculation by the precipitation rate theory calculation unit 22 are the initial manufacturing conditions sent from the input unit 10 or the manufacturing conditions after being changed by the manufacturing condition estimation unit 30. The initial manufacturing conditions are used only for the first calculation, and the changed manufacturing conditions are used after the second time.

[0061] The manufacturing condition estimation unit 30 determines whether the sent distribution states of M 23 C 6 -type carbides and γ'-phase satisfy the target conditions (the above-mentioned target grain boundary M 23 C 6 -type carbide ratio, the target grain boundary γ'-phase area, and the target intragranular fine γ'-phase area ratio) (Step S15). When the distribution states of M 23 C 6 -type carbides and γ'-phase satisfy the target conditions (the above-mentioned target grain boundary M 23 C 6 -type carbide ratio, the target grain boundary γ'-phase area, and the target intragranular fine γ'-phase area ratio) (Step S15 Yes), the manufacturing condition estimation unit 30 sends the calculated distribution states of M 23 C 6 -type carbides and γ'-phase to the output unit 40. The distribution states of M 23 C 6 -type carbides and γ'-phase satisfy the target conditions (the above-mentioned target grain boundary M23 C 6 When the proportions of MC-type carbides, the target grain boundary γ'-phase area, and the target fine γ'-phase area ratio within the grains do not satisfy the requirements (No in step S15), the manufacturing condition estimation unit 30 changes the manufacturing conditions and sends them to the precipitation rate theory calculation unit 22 (step S16). Thereafter, the Ni-based alloy manufacturing condition estimation apparatus 100 repeats the processes after step S13 until the distribution states of the MC-type carbides and the γ'-phase satisfy the target conditions. 23 C 6 type carbides and the γ'-phase until the distribution states of the MC-type carbides and the γ'-phase satisfy the target conditions.

[0062] (Effect) As described above, according to the Ni-based alloy of the first embodiment, the proportion of the MC-type carbides that can be formed from all the contained carbon except carbon in the precipitated MC-type carbides and deposited at the grain boundaries is 70% or more, the area of the γ'-phase deposited at the grain boundaries per 1 μm is 0.19 μm or less, and the area ratio of the γ'-phase with an equivalent circle diameter of less than 20 nm within the grains to the total area of the grains is 0.1% or less. Therefore, it has excellent high-temperature creep ductility. Further, according to the Ni-based alloy manufacturing condition estimation apparatus 100 according to the first embodiment, the distribution states of the MC-type carbides and the γ'-phase calculated using the equilibrium phase diagram calculation unit 21 and the precipitation rate theory calculation unit 22, the target grain boundary MC-type carbide ratio, the target grain boundary γ'-phase area, and the target fine γ'-phase area ratio within the grains can be used to easily estimate appropriate manufacturing conditions. 23 C 6 Among the type carbides, the proportion deposited at the grain boundaries is 70% or more, the area of the γ'-phase deposited at the grain boundaries per 1 μm is 0.19 μm or less, and the area ratio of the γ'-phase with an equivalent circle diameter of less than 20 nm within the grains to the total area of the grains is 0.1% or less. Therefore, it has excellent high-temperature creep ductility. Further, according to the Ni-based alloy manufacturing condition estimation apparatus 100 according to the first embodiment, the distribution states of the MC-type carbides and the γ'-phase calculated using the equilibrium phase diagram calculation unit 21 and the precipitation rate theory calculation unit 22, the target grain boundary MC-type carbide ratio, the target grain boundary γ'-phase area, and the target fine γ'-phase area ratio within the grains can be used to easily estimate appropriate manufacturing conditions. 2 or less, and the area ratio of the γ'-phase with an equivalent circle diameter of less than 20 nm within the grains to the total area of the grains is 0.1% or less, so it has excellent high-temperature creep ductility. Also, according to the Ni-based alloy manufacturing condition estimation apparatus 100 according to the first embodiment, the MC-type carbides and γ'-phase distribution states calculated using the equilibrium phase diagram calculation unit 21 and the precipitation rate theory calculation unit 22, the target grain boundary MC-type carbide ratio, the target grain boundary γ'-phase area, and the target fine γ'-phase area ratio within the grains can be used to easily estimate appropriate manufacturing conditions. 23 C 6 type carbides and the γ'-phase distribution state and the target grain boundary M 23 C 6 type carbide ratio, the target grain boundary γ'-phase area, and the target fine γ'-phase area ratio within the grains, appropriate manufacturing conditions can be easily estimated.

[0063] <Second Embodiment> Hereinafter, a manufacturing condition estimation device for a Ni-based alloy according to the second embodiment will be described. In this second embodiment, the same components as those in the first embodiment may be denoted by the same reference numerals, and the description thereof may be omitted. FIG. 8 is a block diagram showing the configuration of a manufacturing condition estimation device for a Ni-based alloy according to the second embodiment of the present disclosure. A manufacturing condition estimation device 100A for a Ni-based alloy is an estimation device for manufacturing conditions of a Ni-based alloy containing C, Cr, Al, and Ti. Based on the CALPHAD method from the chemical composition of the Ni-based alloy, an equilibrium diagram calculation unit 21 that calculates the types of precipitates predicted to precipitate in the Ni-based alloy and the volume fraction of each precipitate, and based on the Scheil-Gulliver model from the chemical composition of the Ni-based alloy, a Scheil-Gulliver calculation unit 23 that calculates the types of crystallized products crystallized in the Ni-based alloy and the volume fraction of each crystallized product, the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the tissue conditions (crystal grain size and dislocation density) of the γ-phase serving as the matrix, the types of precipitates calculated by the equilibrium diagram calculation unit 21 and the accompanying input information (parameters determined based on the calculation results of the equilibrium diagram calculation unit 21), and the types of crystallized products calculated by the Scheil-Gulliver calculation unit 23 and the volume fraction of each crystallized product, from which, based on the precipitation kinetics theory, a precipitation kinetics calculation unit 22A that calculates the distribution states of MC-type carbides, M 23 C 6 -type carbides and γ'-phase in the Ni-based alloy, the distribution states of M 23 C 6 -type carbides and γ'-phase calculated by the precipitation kinetics calculation unit 22A, the target grain boundary M 23 C 6 -type carbide ratio which is the target ratio of precipitation at the grain boundaries among the M 23 C 6 -type carbides that can be generated from all the contained carbon excluding carbon in the crystallized MC-type carbides, the target grain boundary γ'-phase area which is the target area of γ'-phase precipitated on the grain boundary per 1 μm, and the target grain interior fine γ'-phase area ratio which is the target area ratio of γ'-phase with an equivalent circle diameter of less than 20 nm in the grain interior to the total area of the crystal grains, a manufacturing condition estimation unit 30 that estimates the manufacturing conditions, are provided. The Ni-based alloy manufacturing condition estimation device 100A further includes an input unit 10 that acquires input information and an output unit 40 that outputs the estimated manufacturing conditions of the Ni-based alloy.

[0064] (Equilibrium phase diagram calculation unit 21) Based on the CALPHAD method, the equilibrium phase diagram calculation unit 21 calculates the types of compounds predicted to precipitate or crystallize in the Ni-based alloy and the volume fraction of each compound from the chemical composition of the Ni-based alloy sent from the input unit 10. As a result of the thermodynamic calculation according to the second embodiment, for example, are the types of compounds (precipitates) and the volume fraction of the compounds (precipitates) in the equilibrium state at each temperature. Based on the types of precipitates and the volume fraction at each temperature calculated by the equilibrium phase diagram calculation unit 21, the types of precipitates sent from the input unit 10 to the precipitation rate theory calculation unit 22A and the accompanying input information (nucleation sites of precipitates (within grains or grain boundaries), interface energy of precipitates, aspect ratio of precipitates, lattice misfit strain of precipitates (in the case of precipitates whose crystal lattice is in agreement with the matrix)) are determined.

[0065] (Scheil-Gulliver calculation unit 23) The Scheil-Gulliver calculation unit 23 calculates the types of precipitates that precipitate in the Ni-based alloy and the volume fraction of each precipitate based on the Scheil-Gulliver model from the chemical composition of the Ni-based alloy sent from the input unit 10. Here, the precipitate refers to a secondary phase other than the matrix that occurs during solidification. By calculating using the Scheil-Gulliver model, at each temperature in the solidification process of cooling the Ni-based alloy with the above-described chemical composition from a high-temperature liquid phase, the type of the existing liquid phase composition and precipitates such as the precipitated MC-type carbide can be calculated, as well as the volume fraction of the precipitate. The calculation of the Scheil-Gulliver calculation unit 23 can be performed, for example, as described in Non-Patent Document 2. The result of the thermodynamic calculation is, for example, the types of precipitates that have precipitated in the solidification process and the volume fraction of the precipitates contained at each temperature. The Scheil-Gulliver calculation unit 23 sends the calculated types of precipitates and the volume fraction of each precipitate to the precipitation kinetics calculation unit 22A. Note that the particle size distribution of the precipitate may be input to the input unit 10 based on the general size range of the precipitate and used in the calculation of the precipitation kinetics calculation unit 22A.

[0066] (Precipitation kinetics calculation unit 22A) The precipitation kinetics calculation unit 22A determines, based on the precipitation kinetics, the MC-type carbide, M in the Ni-based alloy from the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the tissue conditions (crystal grain size and dislocation density) of the γ-phase serving as the matrix, the types of precipitates calculated by the equilibrium phase diagram calculation unit 21 and the accompanying input information (parameters determined based on the calculation results of the equilibrium phase diagram calculation unit 21), and the types of precipitates calculated by the Scheil-Gulliver calculation unit 23 and the volume fraction of each precipitate. 23 C 6Calculate the distribution states of the MC-type carbide and the γ'-phase. Specifically, the precipitation rate calculation unit 22A calculates based on the precipitation theory using the chemical composition of the Ni-based alloy, the manufacturing conditions (heat treatment history based on the manufacturing conditions), the structural conditions of the γ-phase serving as the matrix (crystal grain size and dislocation density), the type of precipitate, the nucleation site of the precipitate (within the crystal grain or at the grain boundary), the interfacial energy of the precipitate, the aspect ratio of the precipitate, the lattice misfit strain of the precipitate (in the case of a precipitate whose crystal lattice is matched with the matrix), the type and composition of the crystallized product, the volume fraction of the crystallized product, and the particle size distribution of the crystallized product. The MC-type carbide, M 23 C 6 Calculate the distribution states of the carbide and the γ'-phase. M 23 C 6 The distribution states of the carbide and the γ'-phase include the position and area of the γ'-phase and the position and area of the M 23 C 6 carbide. The precipitation rate calculation unit 22A sends the calculated distribution states of the M 23 C 6 carbide and the γ'-phase to the manufacturing condition estimation unit 30. The manufacturing conditions used in the calculation by the precipitation rate calculation unit 22A are the initial manufacturing conditions sent from the input unit 10 or the manufacturing conditions after being changed by the manufacturing condition estimation unit 30.

[0067] Next, a method for estimating the manufacturing conditions of a Ni-based alloy using the Ni-based alloy manufacturing condition estimation apparatus 100A of the present disclosure will be described.

[0068] FIG. 9 is a flowchart of a method for estimating the manufacturing conditions of a Ni-based alloy according to the second embodiment of the present disclosure. In the Ni-based alloy manufacturing condition estimation apparatus 100A, when the manufacturing condition estimation process starts, the input unit 10 acquires the above-described input information such as the chemical composition and manufacturing conditions of the Ni-based alloy from a storage unit (not shown), and sends the acquired input information to the equilibrium diagram calculation unit 21 (step S11). The input information may be manually input.

[0069] The equilibrium diagram calculation unit 21 that has received the input information calculates the types of precipitates predicted to precipitate in the Ni-based alloy and the volume fraction of each precipitate based on the CALPHAD method from the chemical composition of the Ni-based alloy sent from the input unit 10. Next, based on the types and volume fractions of the precipitates at each temperature calculated by the equilibrium diagram calculation unit 21, the equilibrium diagram calculation unit 21 determines the types of precipitates sent from the input unit 10 to the precipitation rate theory calculation unit 22 and the accompanying input information (nucleation sites of precipitates (inside or at the grain boundaries of grains), interface energy of precipitates, aspect ratio of precipitates, lattice misfit strain of precipitates (in the case of precipitates where the matrix and crystal lattice are matched)) (step S12A). The types and volume fractions of the precipitates to be calculated are the types and volume fractions of the precipitates at each temperature within a predetermined temperature range. The predetermined temperature range is the temperature range of the assumed manufacturing conditions (thermal history).

[0070] The Scheil-Gulliver calculation unit 23 calculates the types of crystallized products that crystallize in the Ni-based alloy and the volume fraction of each crystallized product based on the Scheil-Gulliver model from the chemical composition of the Ni-based alloy sent from the input unit 10, and sends the calculated types of crystallized products and the volume fraction of each crystallized product to the precipitation rate theory calculation unit 22A (step S13).

[0071] Receiving the calculated types of precipitates and the accompanying input information (parameters determined based on the calculation results of the equilibrium diagram calculation unit 21), and the types of crystallized products and the volume fraction of each crystallized product, the precipitation rate theory calculation unit 22A determines from the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the tissue conditions of the γ-phase serving as the matrix (crystal grain size and dislocation density), the types of precipitates calculated by the equilibrium diagram calculation unit and the accompanying input information (parameters determined based on the calculation results of the equilibrium diagram calculation unit 21), and the types of crystallized products and the volume fraction of each crystallized product calculated by the Scheil-Gulliver calculation unit 23, based on the precipitation rate theory, the distribution states of MC-type carbides, M 23 C 6 -type carbides and γ'-phase in the Ni-based alloy, and calculates the M 23 C 6Send the distribution states of the M

[0072] type carbide and the γ' phase to the manufacturing condition estimation unit 30. (Step S14). The manufacturing conditions used in the calculation by the precipitation rate theory calculation unit 22A are the initial manufacturing conditions sent from the input unit 10 or the manufacturing conditions after being changed by the manufacturing condition estimation unit 30. Note that the initial manufacturing conditions are used only for the first calculation, and for the second and subsequent calculations, the manufacturing conditions after being changed are used. 23 C 6 The manufacturing condition estimation unit 30 determines whether the distribution states of the M 23 C 6 type carbide and the γ' phase satisfy the target conditions (the above-mentioned target grain boundary M 23 C 6 type carbide ratio, the target grain boundary γ' phase area, and the target intragranular fine γ' phase area ratio) (Step S15). When the distribution states of the M 23 C 6 type carbide and the γ' phase satisfy the target conditions (the above-mentioned target grain boundary M 23 C 6 type carbide and the γ' phase distribution states calculated by the manufacturing condition estimation unit 30 are sent to the output unit 40. When the distribution states of the M 23 C 6 type carbide and the γ' phase do not satisfy the target conditions (the above-mentioned target grain boundary M 23 C 6 type carbide ratio, the target grain boundary γ' phase area, and the target intragranular fine γ' phase area ratio) (Step S15 No), the manufacturing condition estimation unit 30 changes the manufacturing conditions and sends them to the precipitation rate theory calculation unit 22A (Step S16). Thereafter, the Ni-based alloy manufacturing condition estimation apparatus 100A repeats the processes after Step S13 until the distribution states of the M 23 C 6 type carbide and the γ' phase satisfy the target conditions.

[0073] (Effect) According to the manufacturing condition estimation device 100A of the Ni-based alloy according to the second embodiment described above, M calculated using the equilibrium phase diagram calculation unit 21, the Scheil-Gulliver calculation unit 23, and the precipitation rate theory calculation unit 22A 23 C 6 type carbide and the distribution state of the γ' phase, and the target grain boundary M 23 C 6 type carbide ratio, the target grain boundary γ' phase area, and the target intragranular fine γ' phase area ratio, it is possible to easily estimate appropriate manufacturing conditions. Also, although the precipitation rate theory calculation unit 22A can only calculate the precipitation behavior in the solid phase, in an actual Ni-based alloy, MC-type carbides crystallize from the liquid phase during solidification when melting the ingot, consuming the carbon added to the material, thus affecting the subsequent carbide precipitation behavior in the solid phase. In the manufacturing condition estimation device 100A of the Ni-based alloy according to the second embodiment, the Scheil-Gulliver calculation unit 23 can be used to calculate the amount and chemical composition of MC-type carbides during solidification, and M 23 C 6 type carbide precipitation behavior can be calculated more accurately.

[0074] FIG. 10 is a diagram showing an example of the hardware configuration of the Ni-based alloy production condition estimation apparatuses 100 and 100A according to each embodiment. The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input / output interface 904, and a communication interface 905. The above-described Ni-based alloy production condition estimation apparatuses 100 and 100A are implemented on the computer 900. Then, the operations of the above-described input unit 10, equilibrium diagram calculation unit 21, precipitation rate theory calculation units 22 and 22A, Scheil-Gulliver calculation unit 23, and production condition estimation unit 30 are stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903 and expands it in the main storage device 902, and executes the above processing according to the program. Further, the CPU 901 secures a storage area in the main storage device 902 according to the program. Also, the CPU 901 secures a storage area in the auxiliary storage device 903 for storing data during processing according to the program. The output unit 40 is connected via the input / output interface 904. Therefore, the output unit 40 may or may not be a component of the computer 900.

[0075] A program for realizing all or part of the functions of the Ni-based alloy manufacturing condition estimation devices 100 and 100A may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to perform the processing by each functional unit. Here, the "computer system" shall include hardware such as an OS and peripheral devices. Also, the "computer system" shall include a homepage providing environment (or display environment) if a WWW system is being used. Further, the "computer-readable recording medium" refers to portable media such as CDs, DVDs, USBs, and storage devices such as hard disks built into a computer system. Also, when this program is distributed to the computer 900 via a communication line, the computer 900 that has received the distribution may expand the program in the main storage device 902 and execute the above processing. Also, the above program may be for realizing a part of the aforementioned functions, and may further be capable of being realized in combination with a program already recorded in the computer system for the aforementioned functions.

[0076] In other embodiments, the manufacturing condition estimation devices 100 and 100A may include, in addition to or instead of the above configuration, a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device). Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), FPGA (Field Programmable Gate Array), etc. In this case, part or all of the functions realized by the processor may be realized by the integrated circuit.

[0077] As described above, some embodiments according to the present disclosure have been explained. However, all of these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, as well as in the invention described in the claims and the equivalent scope thereof.

Example

[0078] Next, examples of the present invention will be described. However, the conditions in the examples are one example of the conditions adopted to confirm the feasibility and effects of the present invention, and the present invention is not limited to this one example of conditions. The present invention can adopt various conditions as long as it does not deviate from the gist of the present invention and achieves the object of the present invention.

[0079] (Estimation of manufacturing conditions) Using the Ni-based alloy manufacturing condition estimation device of FIG. 8, equilibrium diagram calculation, Scheil-Gulliver calculation, and precipitation rate theory calculation were performed, and the manufacturing conditions were explored so as to satisfy all of the following conditions 1 to 3. As the chemical composition, Udimet (registered trademark) 520 having the above-described chemical composition was used. Condition 1: The proportion of M 23 C 6 type carbides that precipitate at the grain boundaries among all the carbon-containing carbides that can be generated from all the carbon except for the carbon in the precipitated MC-type carbides is 70% or more Condition 2: The area of the γ' phase precipitating at the grain boundaries per 1 μm is 0.19 μm 2 or less Condition 3: The area ratio of the γ' phase with an equivalent circle diameter of less than 20 nm in the grains to the total area of the grains is 0.1% or less

[0080] (Estimated manufacturing conditions) The manufacturing conditions estimated by the above method were as follows. Solution heat treatment process Holding temperature: 1100 to 1140 °C Holding time: 1 to 10 hours First aging treatment process Holding temperature: 810 - 860 °C Holding time: 20 - 100 hours Final aging treatment process Holding temperature: 740 - 780 °C Holding time: 4 - 50 hours

[0081] (Sample preparation) With reference to the above manufacturing conditions, solution treatment, first aging treatment, and final aging treatment were performed on Udimet (registered trademark) 520 under the conditions in Table 1 to obtain Ni - based alloys of Examples 1 - 3 and Comparative Examples 1 and 2.

[0082] "Ratio of M 23 C 6 type carbides at grain boundaries" The ratio of M 23 C 6 type carbides at grain boundaries was measured by the following method. Each Ni - based alloy was cut out, and the cross - section was polished to prepare an observation sample. Observation was carried out using a field emission scanning electron microscope (FE - SEM), and it was preliminarily confirmed that M 23 C 6 type carbides were precipitated only at grain boundaries. Each Ni - based alloy was cut out, electrolyzed with an electrolyte solution, filtered with a filter, and the residue was collected. The residue was decomposed with an acid, and the elemental amounts in the residue were measured by inductively coupled plasma optical emission spectrometry. Also, X - ray diffraction measurement of the residue was performed to identify the precipitation phase. From the equilibrium phase diagram calculation, the compositional element ratio of the identified precipitation phase was obtained. From these, the amount of M 23 C 6 type carbides contained in the residue was calculated. On the other hand, the maximum amount of M 23 C 6 type carbides that could be generated from all the contained carbon excluding carbon in the precipitated MC - type carbides was obtained by equilibrium phase diagram calculation and Scheil - Gulliver calculation. The amount of M 23 C 6 type carbides contained in the residue was divided by the maximum amount of M 23 C 6 type carbides that could be generated from all the contained carbon excluding carbon in the precipitated MC - type carbides to obtain the ratio of M 23 C 6The ratio of the type carbide was determined. Grain boundary M 23 C 6 When the ratio of the type carbide satisfies Condition 1, it is marked as ○, and when it does not satisfy Condition 1, it is marked as ×. The obtained results are shown in Table 1.

[0083] "Area of γ' phase precipitated on grain boundaries per 1 μm" The grain boundary γ' phase area was measured by the following method. Each Ni-based alloy was cut out, and the cross-section was polished to prepare an observation sample. Observation was carried out using a field emission scanning electron microscope (FE-SEM). For each observation sample, three fields of view (one field of view area: 90 μm 2 ) were photographed at a magnification of 10,000 times, and the white regions on the grain boundaries within each field of view were regarded as the γ' phase precipitated on the grain boundaries. The area of the γ' phase precipitated on the grain boundaries and the length of the grain boundaries within each field of view were measured using image analysis software. The grain boundary γ' phase area was obtained by dividing the total area of the γ' phase precipitated on the obtained grain boundaries by the total length of the grain boundaries. When the obtained grain boundary γ' phase area satisfies Condition 2, it is marked as ○, and when it does not satisfy, it is marked as ×. The obtained results are shown in Table 1.

[0084] "Area ratio of γ' phase with an equivalent circle diameter of less than 20 nm in the grains to the total area of the grains" The area ratio of fine γ' phase in grains was measured by the following method. Each Ni-based alloy was cut out, and the cross-section was polished to prepare an observation sample. Observation was carried out using a field emission scanning electron microscope (FE-SEM). For each sample, three fields of view (one field of view area: 10 μm 2 ) were photographed at a magnification of 30,000 times, and the white regions within the grains and with an equivalent circle diameter of less than 20 nm within each field of view were regarded as the fine γ' phase precipitated within the grains. The area of the fine γ' phase precipitated within the grains and the area of the grains within each field of view were measured using image analysis software. The area ratio of fine γ' phase with an equivalent circle diameter of less than 20 nm precipitated within the grains of all the measured grains was obtained by dividing the total area by the total area of the grains. When the obtained area ratio of fine γ' phase in grains satisfies Condition 3, it is marked as ○, and when it does not satisfy Condition 3, it is marked as ×. The obtained results are shown in Table 1.

[0085] (Creep test) Smooth round bar creep test specimens (parallel part diameter 6 mm × parallel part length 30 mm) were taken from the Ni-based alloys of Examples 1 to 3 and Comparative Examples 1 and 2. Next, creep tests were performed on each creep test specimen at the test temperatures and test stresses shown in Table 1, and the creep rupture time, rupture elongation, and rupture reduction were measured. The obtained results are shown in Table 1. A creep rupture time of 300 hours or more was considered a pass. A rupture elongation of 10% or more was considered a pass. A rupture reduction of 20% or more was considered a pass.

[0086]

Table 1

[0087] The Ni-based alloys of Examples 1 to 3 satisfied all the conditions of Conditions 1 to 3, so good results were obtained in terms of rupture elongation and rupture reduction, indicating excellent high-temperature creep ductility. On the other hand, the Ni-based alloy of Comparative Example 1 had a high holding temperature for the primary aging treatment and did not satisfy the conditions of Condition 2. Therefore, the rupture elongation and rupture reduction were unqualified. The Ni-based alloy of Comparative Example 2 had a high holding temperature for the primary aging treatment and a short holding time for the final aging treatment, and did not satisfy the conditions of Condition 2 and Condition 3. Therefore, the rupture elongation and rupture reduction were unqualified. From the above results, it became clear that the Ni-based alloy of the present disclosure exhibits excellent high-temperature creep ductility. It was also confirmed that the optimum manufacturing conditions can be estimated by the manufacturing condition estimation device for Ni-based alloys.

[0088] <Appendix> The Ni-based alloy and the manufacturing condition estimation device for Ni-based alloys described in the above embodiments are understood as follows, for example.

[0089] (1) The manufacturing condition estimation device 100 for Ni-based alloys according to the first aspect of the present disclosure is An estimation device for the manufacturing conditions of a Ni-based alloy containing C, Cr, Al, and Ti, An equilibrium phase diagram calculation unit 21 that calculates the types of precipitates predicted to precipitate in the Ni-based alloy and the volume fraction of each precipitate based on the CALPHAD method from the chemical composition of the Ni-based alloy, From the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the structural conditions (crystal grain size and dislocation density) of the γ-phase serving as the matrix, the types of the precipitates calculated by the equilibrium phase diagram calculation unit 21, and the input information associated therewith (parameters determined based on the calculation results of the equilibrium phase diagram calculation unit 21), based on the precipitation kinetics theory, MC-type carbides, M 23 C 6 type carbides, and the distribution state of the γ' phase are calculated by a precipitation kinetics calculation unit 22; Based on the distribution state of the M 23 C 6 type carbides and the γ' phase calculated by the precipitation kinetics calculation unit 22, the target proportion of the M 23 C 6 type carbides that precipitate at the grain boundaries, which is the target grain boundary M 23 C 6 type carbide ratio, the target grain boundary γ' phase area, which is the target area of the γ' phase that precipitates at the grain boundaries per 1 μm, and the target grain interior fine γ' phase area ratio, which is the target ratio of the area of the γ' phase with a circle equivalent diameter of less than 20 nm in the grain interior to the total area of the grains, the manufacturing conditions are estimated by a manufacturing condition estimation unit 30.

[0090] By doing so, the manufacturing conditions of the Ni-based alloy can be easily estimated.

[0091] (2) The manufacturing condition estimation device 100 for a Ni-based alloy according to the second aspect of the present disclosure is the manufacturing condition estimation device for a Ni-based alloy in (1), wherein the target grain boundary M 23 C 6 type carbide ratio is 70% or more.

[0092] By doing so, the manufacturing conditions of a Ni-based alloy excellent in high-temperature creep ductility can be easily estimated.

[0093] (3) The manufacturing condition estimation device 100 for Ni-based alloys according to the third aspect of the present disclosure is the manufacturing condition estimation device for Ni-based alloys of (1) or (2), wherein the target grain boundary γ' phase area is 0.19 μm 2 is as follows.

[0094] By doing so, it is possible to easily estimate the manufacturing conditions for Ni-based alloys with excellent high-temperature creep ductility.

[0095] (4) The manufacturing condition estimation device 100 for Ni-based alloys according to the fourth aspect of the present disclosure is the manufacturing condition estimation device for Ni-based alloys of any one of (1) to (3), wherein the target volume fraction of fine γ' phase in the grain is 0.1% or less.

[0096] By doing so, it is possible to easily estimate the manufacturing conditions for Ni-based alloys with excellent high-temperature creep ductility.

[0097] (5) The manufacturing condition estimation device 100 for Ni-based alloys according to the fifth aspect of the present disclosure is the manufacturing condition estimation device for Ni-based alloys of any one of (1) to (4), and further includes a Scheil-Gulliver calculation unit 23 that calculates the types of precipitates crystallized in the Ni-based alloy and the volume fraction of each precipitate based on the Scheil-Gulliver model from the chemical composition of the Ni-based alloy. The precipitation rate theory calculation unit 22 uses the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the tissue conditions (crystal grain size and dislocation density) of the γ phase serving as the matrix, the types of precipitates calculated by the equilibrium diagram calculation unit 21, and the input information associated therewith (parameters determined based on the calculation results of the equilibrium diagram calculation unit 21), and the types of the precipitates calculated by the Scheil-Gulliver calculation unit 23 and the volume fraction of each precipitate, to calculate the distribution states of the MC-type carbides, M 23 C 6 type carbides and γ' phase in the Ni-based alloy.

[0098] By doing so, it is possible to easily estimate the manufacturing conditions for Ni-based alloys with excellent high-temperature creep ductility. Also, the M can be more accurately23 C 6 It is possible to calculate the precipitation behavior of carbide of type C.

[0099] (6) The Ni-based alloy manufacturing condition estimation device 100 according to the sixth aspect of the present disclosure is the Ni-based alloy manufacturing condition estimation device according to any one of (1) to (5), wherein the chemical composition of the Ni-based alloy is, by mass%, C: 0.02 to 0.06%, Si: 0.15% or less, Mn: 0.15% or less, P: 0.01% or less, S: 0.005% or less, Cu: 0.1% or less, Cr: 18 to 20%, Mo: 5.5 to 7.0%, W: 0.8 to 1.2%, Co: 11 to 14%, Al: 1.8 to 2.3%, Ti: 2.90 to 3.25%, Fe: 2% or less, B: 0.004 to 0.010% contains, and the balance consists of Ni and unavoidable impurities.

[0100] By doing so, it is possible to estimate the manufacturing conditions of a Ni-based alloy excellent in high-temperature creep ductility.

[0101] (7) The Ni-based alloy according to the seventh aspect of the present disclosure is such that the chemical composition is, by mass%, C: 0.02 to 0.06%, Si: 0.15% or less, Mn: 0.15% or less, P: 0.01% or less, S: 0.005% or less, Cu: 0.1% or less, Cr: 18 to 20%, Mo: 5.5 to 7.0%, W: 0.8 to 1.2%, Co: 11 to 14%, Al: 1.8 to 2.3%, Ti: 2.90 to 3.25%, Fe: 2% or less, B: 0.004 to 0.010% containing, the balance consisting of Ni and unavoidable impurities, M that can be generated from all the contained carbon except for the carbon in the precipitated MC-type carbide, 23 C 6 the ratio of the M C 2 type carbide precipitating at the grain boundaries is 70% or more, the area of the γ'-phase precipitating at the grain boundaries per 1 μm is 0.19 μm

[0102] By doing so, the high-temperature creep ductility can be improved.

Explanation of Reference Numerals

[0103] 10 Input unit, 21 Equilibrium diagram calculation unit, 22 Precipitation rate theory calculation unit, 23 Scheil-Gulliver calculation unit, 30 Manufacturing condition estimation unit, 40 Output unit, 100 Manufacturing condition estimation device for Ni-based alloy

Claims

1. An apparatus for estimating manufacturing conditions of a Ni-based alloy containing C, Cr, Al, and Ti, comprising: an equilibrium phase diagram calculation unit configured to calculate, based on a CALPHAD method, types of precipitates predicted to precipitate in the Ni-based alloy and volume fractions of the respective precipitates from a chemical composition of the Ni-based alloy; Based on the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the structural conditions of the γ-phase serving as the matrix, the types of the precipitates calculated by the equilibrium phase diagram calculation unit, and the parameters determined based on the calculation results of the equilibrium phase diagram calculation unit, the distribution states of the MC-type carbide, M ２３ C ６ -type carbide, and γ'-phase in the Ni-based alloy are calculated by a precipitation rate theory calculation unit, The M calculated by the precipitation rate calculation unit ２３ C ６ type carbide and the distribution state of the γ' phase, the M that can be generated from all the contained carbon except carbon in the precipitated MC type carbide ２３ C ６ The target grain boundary M ２３ C ６ type carbide ratio, the target grain boundary γ' phase area which is the target of the area of the γ' phase precipitated on the grain boundary per 1 μm, and the target grain interior fine γ' phase area ratio which is the target of the area ratio of the γ' phase having a circle equivalent diameter of less than 20 nm in the grain interior with respect to the total area of the grains, and estimating the manufacturing conditions based on these, a manufacturing condition estimation unit An apparatus for estimating manufacturing conditions of a Ni-based alloy, comprising the above.

2. The target grain boundary M ２３ C ６ The manufacturing condition estimation apparatus for Ni-based alloy according to claim 1, wherein the proportion of the type carbide is 70% or more.

3. The area of the target grain boundary γ'-phase is 0.19 μm ２ The Ni-based alloy manufacturing condition estimation device according to claim 1, wherein the area is 0.19 μm or less

4. The apparatus for estimating manufacturing conditions of a Ni-based alloy according to claim 1, wherein a fine γ'-phase area ratio within a target crystal grain is 0.1% or less.

5. further comprising a Scheil-Gulliver calculation unit configured to calculate, based on a Scheil-Gulliver model, types of crystallized products crystallized in the Ni-based alloy and volume fractions of the respective crystallized products from the chemical composition of the Ni-based alloy; The precipitation rate calculation unit calculates the distribution state of the M ２３ C ６ type carbide and the γ' phase in the Ni-based alloy based on the chemical composition of the Ni-based alloy, the manufacturing conditions of the Ni-based alloy, the tissue conditions of the γ phase serving as the matrix, the types of the precipitates calculated by the equilibrium diagram calculation unit and the parameters determined based on the calculation results of the equilibrium diagram calculation unit, and the types of the crystallized products and the volume fraction of each crystallized product calculated by the Scheil-Gulliver calculation unit. The manufacturing condition estimation device for a Ni-based alloy according to claim 1 or claim 2.

6. wherein the chemical composition of the Ni-based alloy is in mass %, C: 0.02 to 0.06%, Si: 0.15% or less, Mn: 0.15% or less, P: 0.01% or less, S: 0.005% or less, Cu: 0.1% or less, Cr: 18 to 20%, Mo: 5.5 to 7.0%, W: 0.8 to 1.2%, Co: 11 to 14%, Al: 1.8 to 2.3%, Ti: 2.90 to 3.25%, Fe: 2% or less, B: 0.004 to 0.010% and the balance consists of Ni and unavoidable impurities; The apparatus for estimating manufacturing conditions of a Ni-based alloy according to claim 1.

7. A Ni-based alloy having a chemical composition in mass %, C: 0.02 to 0.06%, Si: 0.15% or less, Mn: 0.15% or less, P: 0.01% or less, S: 0.005% or less, Cu: 0.1% or less, Cr: 18 to 20%, Mo: 5.5 to 7.0%, W: 0.8 to 1.2%, Co: 11 to 14%, Al: 1.8 to 2.3%, Ti: 2.90 to 3.25%, Fe: 2% or less, B: 0.004 to 0.010% and the balance consists of Ni and unavoidable impurities, wherein an area ratio of γ'-phase having an equivalent circle diameter of less than 20 nm within the crystal grain to a total area of the crystal grain is 0.1% or less. M that can be generated from all the contained carbon excluding carbon in the precipitated MC-type carbide ２３ C ６ The proportion of the MC-type carbide that precipitates at the grain boundaries is 70% or more, The area of the γ' phase precipitated at the grain boundaries per 1 μm is 0.19 μm ２ or less, ​

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