Preforming raft control method for double-state R-type gamma'raft-shaped structure in weldable Ni3Al-based high-temperature alloy

Abstract

The invention discloses a pre-shaped raft control method for a double-state R-type gamma'raft-shaped structure in a weldable Ni3Al-based high-temperature alloy, and belongs to the technical field of weldable Ni3Al-based high-temperature alloy structure regulation and control. According to the method disclosed by the invention, medium-temperature precreep parameters and heat treatment parameters of the weldable Ni3Al-based high-temperature alloy are regulated and controlled, so that preforming raft control of a dual-state R-type gamma'raft-shaped structure in the weldable Ni3Al-based high-temperature alloy is realized in two different modes of precreep and heat treatment respectively; and the weldable Ni3Al-based high-temperature alloy with the double-state R-type gamma'raft structure in different states is obtained, so that the high-temperature tensile property and the high-temperature creep property of the weldable Ni3Al-based high-temperature alloy are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of multiphase structure control of Ni3Al-based high-temperature alloys, and in particular to a pre-shaped raft control method for a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy. Background Art

[0002] Compared with traditional nickel-based high-temperature alloys, Ni3Al-based high-temperature alloys have high melting point (up to 1395 ° C or above), high γ′ phase volume fraction (up to 80 vol.%), low density (8.0 ~ 8.5 g / cm 3 ), excellent high-temperature mechanical properties and corrosion resistance, and are widely used in the automotive, aerospace, energy and other fields. However, the general non-weldability of Ni3Al-based high-temperature alloys still limits the further promotion and application of this type of high-temperature alloys. Due to the large addition of Fe (11.7%) and Cr (7.6%) components in the weldable Ni3Al-based high-temperature alloy, 19.4 vol.% of interdendritic β phase is introduced, thereby solving the weldability problem. However, the introduction of β phase, while improving weldability, also significantly reduces the high-temperature mechanical properties, especially the high-temperature creep properties, of the weldable Ni3Al-based high-temperature alloy with complex multiphase structure.

[0003] Compared with traditional nickel-based high-temperature alloys, weldable Ni3Al-based high-temperature alloys have a complex multiphase structure, mainly composed of γ′+γ two-phase structure, interdendritic β phase and γ′-envelope structure and Cr 23 The steady-state creep phase of weldable Ni3Al-based superalloys is primarily controlled by the γ′+γ two-phase structure. During different heat treatments and medium-temperature creep, the γ′+γ two-phase structure in the alloy can form three different types of γ′ raft structures, significantly improving the alloy's medium-temperature creep performance. The corresponding creep resistance, from smallest to largest, is as follows: N-type γ′ rafted superalloy, R-type γ′ rafted superalloy, and dual-state R-type γ′ rafted superalloy.

[0004] Unlike the common N-type γ′ rafting orientation in conventional nickel-based superalloys, the dual-state R-type γ′ rafting in weldable Ni3Al-based superalloys is not simply parallel or perpendicular to the stress axis. Instead, the primary and secondary γ′ phases in the γ′+γ two-phase microstructure form a complex network structure, significantly enhancing the alloy's creep resistance at both medium and high temperatures. Therefore, in weldable Ni3Al-based superalloys, the question of how to gradually raft the primary and secondary γ′ phases in the γ′+γ two-phase microstructure into a dual-state R-type γ′ raft, thereby effectively controlling the pre-formation of the dual-state R-type γ′ raft, is of great research value. Therefore, the present invention utilizes different pre-creep and heat treatment methods to achieve pre-formation control of the dual-state R-type γ′ raft in weldable Ni3Al-based superalloys.

[0005] To this end, it is necessary to formulate appropriate medium-temperature pre-creep and heat treatment parameters according to the heat treatment window of the weldable Ni3Al-based high-temperature alloy. Through two different methods of pre-creep and heat treatment, the pre-shaped raft control of the dual-state R-type γ′ raft structure in the weldable Ni3Al-based high-temperature alloy can be achieved respectively, and weldable Ni3Al-based high-temperature alloys with dual-state R-type γ′ raft structure in different states can be obtained, so as to significantly improve the high-temperature tensile and high-temperature creep properties of the weldable Ni3Al-based high-temperature alloy. Summary of the Invention

[0006] The purpose of the present invention is to provide a pre-shaped raft control method for a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy. By regulating the medium-temperature pre-creep parameters and controlling the heat treatment parameters of the weldable Ni3Al-based high-temperature alloy, the pre-shaped raft control of the dual-state R-type γ′ raft structure in the weldable Ni3Al-based high-temperature alloy is achieved in two different ways, and weldable Ni3Al-based high-temperature alloys with dual-state R-type γ′ raft structures in different states are obtained, thereby significantly improving the high-temperature tensile and high-temperature creep properties of the weldable Ni3Al-based high-temperature alloy.

[0007] To achieve the above object, the present invention provides a method for controlling a preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy, comprising the following steps:

[0008] S1. Select weldable Ni3Al-based high-temperature alloy and cut the specimens into two groups, A and B.

[0009] S2, the two groups of samples A and B in S1 are subjected to a high temperature aging treatment in a high temperature heat treatment furnace;

[0010] S3, subjecting the sample of group A in S2 to a medium-temperature pre-creep treatment and performing creep interruption at a specific time to obtain a weldable Ni3Al-based high-temperature alloy having a dual-state R-type γ′ raft structure;

[0011] S4. The samples in group B in S2 were subjected to secondary aging treatment to obtain another weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0012] Preferably, the weldable Ni3Al-based high-temperature alloy contains the following components in weight percentage: 8-9% Al, 7.6% Cr, 12-15% Mo, 0-0.002% W, 0.01-0.1% C, 0.055% Mn, 0.009% Ti, 11.7% Fe, 0.055% Si, 0.018% B, 0.5-1.5% Hf, and the rest is Ni.

[0013] Preferably, in step S2, the high-temperature aging conditions of both groups A and B samples are 1000°C-1000h, and water cooling treatment is performed after the high-temperature aging treatment.

[0014] Preferably, in step S3, the medium-temperature pre-creep treatment conditions of group A samples are 800°C / 220 MPa.

[0015] Preferably, in step S3, when the samples in group A are subjected to medium-temperature pre-creep treatment, the creep is interrupted after 100 to 150 hours, and then cooled in the furnace to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0016] Preferably, in step S4, the secondary aging treatment condition of group B samples is 800°C-1000h, and after the secondary aging treatment, the samples are cooled in the furnace to obtain another weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0017] The present invention discloses a pre-shaped raft control method for a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy, which has the following beneficial effects:

[0018] (1) The present invention uses two different methods, pre-creep and heat treatment, to finally make the primary and secondary γ′ phases in the γ′+γ two-phase structure of the weldable Ni3Al-based high-temperature alloy gradually form a dual-state R-type γ′ raft structure, thereby effectively improving the high-temperature creep performance of the weldable Ni3Al-based high-temperature alloy.

[0019] (2) The present invention can make the primary γ′ phase raft in the γ′+γ two-phase structure of the alloy into a large-sized R-type γ′ raft structure by subjecting the weldable Ni3Al-based high-temperature alloy to a long-term aging treatment at 1000℃-1000h and then a water cooling treatment, and promote the rapid precipitation of a large number of nearly spherical secondary γ′ phases in the γ channel of the γ′+γ two-phase structure; the subsequent 800℃ / 220MPa medium-temperature pre-creep treatment for 100-150h followed by furnace cooling, or 800℃-1000h long-term aging followed by furnace cooling treatment, can further promote the secondary γ′ phase raft in the γ′+γ two-phase structure of the alloy into a small-sized R-type γ′ raft structure, thereby ultimately obtaining a dual-state R-type γ′ raft structure with higher creep resistance in the weldable Ni3Al-based high-temperature alloy.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of a method for controlling a preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy according to the present invention;

[0022] Figure 2 This is a SEM image of a weldable Ni3Al-based high-temperature alloy having a dual-state R-type γ′ raft structure prepared in specific embodiment 1;

[0023] Figure 3 This is a SEM image of a weldable Ni3Al-based high-temperature alloy having a dual-state R-type γ′ raft structure prepared in specific embodiment 2. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0025] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0026] Furthermore, it should be understood that although this specification describes the embodiments, not every embodiment includes only one independent technical solution. This description is for clarity only. Those skilled in the art should consider the specification as a whole. The technical solutions in the various embodiments may also be appropriately combined to form other embodiments that are understandable to those skilled in the art. These other embodiments are also encompassed within the scope of protection of the present invention.

[0027] As the instructions attached Figure 1 As shown in the flowchart, the present invention provides a method for controlling a preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy, comprising the following steps:

[0028] S1. Select weldable Ni3Al-based high-temperature alloy and cut the specimens into two groups, A and B.

[0029] S2. The two groups of samples A and B in S1 are subjected to a high-temperature aging treatment in a high-temperature heat treatment furnace.

[0030] S3. The samples of group A in S2 are subjected to medium-temperature pre-creep treatment and creep interruption at a specific time to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0031] S4. The samples of group B in S2 are subjected to secondary aging treatment at a specific time and temperature to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0032] The weldable Ni3Al-based high-temperature alloy contains the following components by weight percentage: 8-9% Al, 7.6% Cr, 12-15% Mo, 0-0.002% W, 0.01-0.1% C, 0.055% Mn, 0.009% Ti, 11.7% Fe, 0.055% Si, 0.018% B, 0.5-1.5% Hf, and the rest is Ni.

[0033] In step S2, the high-temperature aging condition for the two groups of samples is 1000°C-1000h, and water cooling treatment is performed after aging.

[0034] In step S3, the aged group A samples were subjected to a medium-temperature pre-creep treatment at 800°C / 220 MPa.

[0035] In step S3, when the samples of group A are subjected to medium temperature pre-creep treatment, the creep is interrupted after 100 to 150 hours, and then cooled in the furnace to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0036] In step S4, the secondary aging treatment conditions of group B samples are 800°C-1000h, and after the secondary aging, they are cooled in the furnace to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0037] The following further describes a method for controlling a pre-shaped raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy in conjunction with an embodiment:

[0038] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0039] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0040] Unless otherwise specified in the present invention, the reagents, instruments, and equipment used are those commonly used by those skilled in the art. Specific embodiment one:

[0042] This embodiment provides a method for controlling the pre-shaped raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based superalloy, wherein the pre-shaped raft is controlled by a pre-creep method of a single high-temperature aging process followed by a medium-temperature pre-creep process. The weldable Ni3Al-based superalloy comprises the following components, expressed in weight percentage:

[0043] Al Cr Mo W C Mn Ti Fe Si B Hf Ni 8.9 7.6 13.7 <0.002 0.077 0.055 0.009 11.7 0.055 0.018 0.9 Bal

[0044] The specific steps include:

[0045] S1. Select a weldable Ni3Al-based high-temperature alloy and cut the specimen.

[0046] S2. Place the sample in S1 in a ceramic crucible and put it into a high-temperature heat treatment furnace for a high-temperature aging treatment of 1000°C-1000h, followed by water cooling.

[0047] S3. The sample in S2 is subjected to medium-temperature pre-creep treatment at 800°C / 220MPa, and the creep is interrupted after 100 to 150 hours. After the interruption, it is cooled in the furnace to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0048] The SEM images of the samples prepared in this example are as follows: Figure 2 As shown in the figure, the combined influence of temperature field and stress field causes the primary and secondary γ′ phases in the γ′+γ two-phase organization to form a network-like raft structure, and the primary and secondary R-type γ′ raft structures together constitute a dual-state R-type γ′ raft structure with a double peak shape. Specific embodiment 2

[0050] This embodiment provides a method for controlling the preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based superalloy by a single high-temperature aging plus a secondary aging heat treatment. The weldable Ni3Al-based superalloy comprises the following components by weight:

[0051] Al Cr Mo W C Mn Ti Fe Si B Hf Ni 8.9 7.6 13.7 <0.002 0.077 0.055 0.009 11.7 0.055 0.018 0.9 Bal

[0052] S1. Select a weldable Ni3Al-based high-temperature alloy and cut the sample;

[0053] S2. Place the sample in S1 in a ceramic crucible and place it in a high-temperature heat treatment furnace for a high-temperature aging treatment at 1000°C for 1000 hours, followed by water cooling.

[0054] S3. The sample in S2 is placed in a ceramic crucible and placed in a high-temperature heat treatment furnace again for secondary aging treatment at 800°C-1000h. After the secondary aging, it is cooled in the furnace to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

[0055] The SEM images of the samples prepared in this example are as follows: Figure 3 As shown, the action of a single temperature field can also cause the primary and secondary γ′ phases in the γ′+γ two-phase organization to form a network-like raft structure. The primary and secondary R-type γ′ raft structures together constitute a dual-state R-type γ′ raft structure with a double peak shape. Compared with Example 1, it takes longer to form the dual-state R-type γ′ raft structure.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for controlling the preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy, characterized in that: The following steps are involved: S1. Select weldable Ni3Al-based high-temperature alloy and cut the specimens into two groups, A and B. S2, the two groups of samples A and B in S1 are subjected to a high temperature aging treatment in a high temperature heat treatment furnace; S3, subjecting the sample of group A in S2 to a medium-temperature pre-creep treatment and performing creep interruption at a specific time to obtain a weldable Ni3Al-based high-temperature alloy having a dual-state R-type γ′ raft structure; S4. The samples in group B in S2 were subjected to secondary aging treatment to obtain another weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

2. The method for controlling the preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy according to claim 1, characterized in that: In step S2, the high-temperature aging conditions for both groups A and B samples are 1000°C-1000h, and water cooling treatment is performed after the high-temperature aging treatment.

3. The method for controlling the preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy according to claim 1, wherein: In step S3, the conditions for the medium-temperature pre-creep treatment of the samples in group A were 800°C / 220 MPa.

4. The method for controlling the preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy according to claim 3, wherein: In step S3, when the samples of group A are subjected to medium temperature pre-creep treatment, the creep is interrupted after 100 to 150 hours, and then cooled in the furnace to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

5. The method for controlling the preformed raft of a dual-state R-type γ′ raft structure in a weldable Ni3Al-based high-temperature alloy according to claim 1, wherein: In step S4, the secondary aging treatment conditions of group B samples are 800°C-1000h. After the secondary aging treatment, the samples are cooled in the furnace to obtain a weldable Ni3Al-based high-temperature alloy with a dual-state R-type γ′ raft structure.

Images