Method for manufacturing powder superalloy

Abstract

A method for manufacturing a powder superalloy. Two pre-alloyed powders having a melting-point difference are used as sintering raw materials, and the sum composition of the two pre-alloyed powders is completely equivalent to the composition of a target powder superalloy; during a hot isostatic pressing process, a low-melting alloy powder melts to form a liquid phase, the liquid phase wets the surface of a high-melting alloy powder, and impurities and an oxide layer on the surface of powder particles are cleaned off; and the liquid phase and the solid phase are rapidly inter-diffused, realizing isothermal solidification and composition homogenization, and finally an equiaxed crystalline powder superalloy structure having a uniform structure and fine grains is formed. The method can effectively avoid original powder particle boundary defects generated by manufacturing a high-performance powder superalloy by means of a conventional hot isostatic pressing process, and does not require the use of an additional processing step or the addition of an additional chemical component to eliminate the defects, thereby realizing the preparation of a powder superalloy formed by means of hot isostatic pressing within a short process.

Description

A method for manufacturing a powder superalloy

[0001] The present disclosure claims priority to the Chinese patent application No. 202410880425.X, filed on July 02, 2024, entitled "A method for manufacturing high-performance powder superalloy with low cost and short process", the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of powder metallurgy superalloy, in particular to a method for manufacturing high-performance powder superalloy with low cost and short process, which realizes short process preparation of powder superalloy without original powder particle boundary defects. BACKGROUND

[0003] Powder superalloy is a kind of high-temperature structural material with no macrosegregation, uniform structure, fine grain and excellent comprehensive mechanical properties, which has become the preferred material for manufacturing key hot end components such as turbine disc, compressor disc and baffle of advanced aero-engine. Currently, powder superalloy is usually manufactured by solid powder hot isostatic pressing process, but the powder superalloy prepared by this process inevitably produces original powder particle boundary defects. This defect is a layer of fine and continuous second phase particles precipitated along the surface of the original solid powder, which hinders the metallurgical bonding between powder particles and is a potential crack source. This defect damages the mechanical properties of powder superalloy, especially the impact toughness and low cycle fatigue performance, seriously endangering the reliability of powder superalloy material [Huang Xina, Guo Sirui, Yue Wen, et al. Research status of original particle boundary of powder superalloy prepared by hot isostatic pressing [J]. Powder Metallurgy Technology, 2023, 41(05): 402-409+419.].

[0004] In order to effectively eliminate or avoid the original powder particle boundary defects of powder superalloy, researchers have conducted extensive research. The current research results show that the second phase particles on the original powder particle boundary are generally related to the alloy composition, usually composed of MC type carbide and oxide, and cannot be eliminated by conventional heat treatment process. At present, the main measures to prevent or eliminate the original powder particle boundary are as follows:(1) Using "hot isostatic pressing + hot plastic processing" process, hot extrusion, isothermal forging and other hot plastic processing of hot isostatic pressing powder superalloy, mechanical crushing of second phase particles on the surface of solid phase powder [a kind of nickel-based powder superalloy and its forming method, publication number: CN111647764A; method for determining critical deformation amount and extrusion process parameters for eliminating powder superalloy PPB, publication number: CN113343516A]. This process can effectively eliminate the original powder particle boundary defects of powder, but it needs expensive large-scale hot plastic processing equipment, greatly increases the process cost, prolongs the process flow, and the stability of the process is poor.(2) Adjusting the composition of superalloy, adding Hf and other strong carbide forming elements in powder metallurgy superalloy, strictly reducing the content of carbon element, reducing the precipitation tendency of carbide on the original powder particle boundary, but this method can only eliminate the original powder particle boundary to a certain extent.(3) Using "powder low temperature heat treatment + hot isostatic pressing" process, first preheat the solid phase powder in a certain temperature range to form stable carbide in the powder, and then perform hot isostatic pressing [a device and method for preparing fine particle size powder superalloy hot isostatic pressed parts, publication number: CN114210977A; a method and device for automatic vacuum degassing of metal powder, publication number: CN114192773A], which can reduce the severity of the original powder particle boundary defects, but cannot completely eliminate the defects, and additional process steps and equipment are needed, increasing the manufacturing cost.(4) Two-step hot isostatic pressing process, first increase the temperature to a higher temperature during heating, then reduce the temperature for hot isostatic pressing sintering [a hot isostatic pressing forming method of nickel-based superalloy powder, publication number: CN110666175A], which can only inhibit the original powder particle boundary defects of powder superalloy to a certain extent, but cannot completely eliminate them, and this process is only suitable for special composition superalloy.(5) Using "powder high temperature atmosphere reduction + hot isostatic pressing" process, the powder is placed in a high temperature CO atmosphere for reduction treatment to remove the oxygen attached to the surface of the powder, avoid the nucleation and growth of carbide and oxide on the surface of the powder particles, and thus eliminate the original powder particle boundary [a device and method for preparing fine particle size powder superalloy hot isostatic pressed parts, publication number: CN114210977A]. This method can eliminate the original powder particle boundary, but it needs additional process steps and special equipment, which increases the process cost.(6) Using the "oscillating pressure sintering" process, this process uses a special process equipment of axial oscillation and pressure to prepare powder superalloy [a method for preparing fine-grained powder superalloy for suppressing the formation of original powder particle boundaries, publication number: CN111304476A], which can effectively eliminate the original powder particle boundary, but only suitable for preparing small experimental samples, and preparing large samples will produce serious density inhomogeneity, which cannot be applied on a large scale.

[0005] It is obvious that thermoplastic processing can effectively eliminate the original powder particle boundary defects of powder superalloy, but it increases the process cost and prolongs the process flow. In addition, other methods to avoid or eliminate the original powder particle boundary are still in the experimental stage, and the process effect is not good. Therefore, it is urgent to develop a process method for preparing powder superalloy without original powder particle boundary defects suitable for industrial production. SUMMARY

[0006] In order to overcome the problems in the related art, the present disclosure provides a method for manufacturing powder superalloy, which realizes low-cost short-process manufacturing without thermoplastic processing or adding other alloy elements, while avoiding the original powder particle boundary defects caused by using hot isostatic pressing process to manufacture high-performance powder superalloy.

[0007] According to a first aspect of the embodiments of the present disclosure, a method for manufacturing powder superalloy is provided, which prepares a sintering raw material, the sintering raw material uses two pre-alloy powders with different melting points, the two pre-alloy powders include a low-melting alloy powder and a high-melting alloy powder, and the total composition of the two pre-alloy powders is completely equivalent to the composition of the target powder superalloy; during the sintering process, the sintering temperature is higher than the melting point of the low-melting alloy powder, so that the low-melting alloy powder is melted to form a liquid phase, and the sintering temperature is lower than the melting point of the high-melting alloy powder, so that the high-melting alloy powder is in the form of solid particles; the liquid phase formed by the melting of the low-melting alloy powder sufficiently wets the surface of the particles, cleans the impurities attached to the surface of the particles, and undergoes solid-liquid interdiffusion with the high-melting alloy powder to realize isothermal solidification, and finally forms a powder superalloy.

[0008] In some embodiments, the method for manufacturing powder superalloy includes the following process steps:

[0009] 1) According to the composition of the target powder superalloy, prepare a low-melting alloy powder and a high-melting alloy powder, the particle size of the low-melting alloy powder and the high-melting alloy powder is less than or equal to 100 microns, and the shape of the low-melting alloy powder and the high-melting alloy powder is near-spherical powder;

[0010] 2) According to the required mass ratio of the target powder superalloy composition, the low-melting alloy powder and the high-melting alloy powder are weighed and uniformly ball-mixed at a ball-mill speed of 120-200 r / min for 120-150 min to obtain a sintering raw material;

[0011] 3) The sintering raw material is filled in a low-carbon steel can, degassed at a high temperature of 180-300 °C, and then vacuum-sealed and welded;

[0012] 4) The can is placed in a hot isostatic pressing device, and hot isostatic pressing sintering is performed by simultaneously increasing the temperature and pressure or by first increasing the temperature and then increasing the pressure; the sintering temperature is 1150-1300 °C, the holding time is 2-4 h, and the sintering pressure is 120-150 MPa;

[0013] 5) After the hot isostatic pressing process is completed, the target powder superalloy is taken out when the furnace temperature cools to room temperature.

[0014] In some embodiments, in the two pre-alloy powders with different melting points, the low-melting alloy powder is a binary, ternary or multi-element alloy powder of the elements Ni, Cr, Co, Ti, Al and Ta in the target powder superalloy, with a melting point lower than 1250 °C, and the volume fraction of the low-melting alloy powder in the sintering raw material is 10%-50%; the composition of the high-melting alloy powder is determined by the composition of the target powder superalloy, and the composition of the high-melting alloy powder is designed according to the requirement that the sum of the compositions of the high-melting alloy powder and the low-melting alloy powder is the composition of the target powder superalloy.

[0015] In some embodiments, the composition of the low-melting alloy powder is Ni-Al-Ta-Ti, with a mass percentage of Ta 14.5-16.5 wt.%, Al 6.0-7.0 wt.%, Ti 14.8-15.8 wt.%, and the balance being Ni. The selected mass percentage composition of the high-melting alloy powder includes but is not limited to Cr 15.5-16.5 wt.%, Co 14.0-15.0 wt.%, Mo 5.0-5.5 wt.%, W 5.0-5.5 wt.%, Nb 2.6-3.0 wt.%, C 0.025-0.045 wt.%, and the balance being Ni.

[0016] In some embodiments, the low melting alloy powder composition is Ni-Cr-Ta-Ti, in mass percent: Cr 11.7-12.5 wt.%, Ta 3.2-4.5 wt.%, Ti 9.2-10.9 wt.%, balance Ni. Selected high melting alloy powder mass percent compositions include, but are not limited to: Cr 11.5-13.5 wt.%, Co 9.0-11.0 wt.%, Mo 1.0-3.5 wt.%, W 9.0-10.5 wt.%, Nb 0.6-1.0 wt.%, C 0.025-0.045 wt.%, balance Ni.

[0017] In some embodiments, the low melting alloy powder composition is Ni-Co-Ti-Al-Ta, in mass percent: Co 13.7-14.5 wt.%, Ti 5.6-7.5 wt.%, Al 3.3-3.9 wt.%, Ta 14.8-19.8 wt.%, balance Ni. Selected high melting alloy powder mass percent compositions include, but are not limited to: Cr 4.5-8.5 wt.%, Co 5.0-7.0 wt.%, Mo 3.0-7.5 wt.%, W 1.0-3.5 wt.%, Nb 1.6-2.0 wt.%, C 0.015-0.025 wt.%, balance Ni.

[0018] In some embodiments, the low melting alloy powder composition is Ni-Cr-Co-Al-Ta, in mass percent: Co 13.7-14.5 wt.%, Cr 5.6-7.5 wt.%, Al 3.2-5.9 wt.%, Ta 18.8-19.8 wt.%, balance Ni. Selected high melting alloy powder mass percent compositions include, but are not limited to: Cr 14.5-18.5 wt.%, Co 15.0-16.0 wt.%, Mo 0.5-3.5 wt.%, W 2.0-1.5 wt.%, Nb 4.6-5.0 wt.%, C 0.015-0.025 wt.%, balance Ni.

[0019] In some embodiments, the low melting alloy powder composition is Ni-Cr-Co-Al-Ti, in mass percent: Cr 15.7-16.5 wt.%, Co 8.2-9.5 wt.%, Al 6.2-7.9 wt.%, Ti 14.8-19.8 wt.%, balance Ni. Selected high melting alloy powder mass percent compositions include, but are not limited to: Cr 14.9-17.1 wt.%, Co 12.1-13.5 wt.%, Mo 3.2-4.1 wt.%, W 4.1-5.0 wt.%, Al 1.9-2.1 wt.%, Nb 1.9-2.7 wt.%, C 0.045-0.065 wt.%, balance Ni.

[0020] In some embodiments, the low melting alloy powder composition is Ni-Ta-Ti, in mass percent: Ta 15.7-16.5 wt.%, Ti 14.8-19.8 wt.%, balance Ni. Selected high melting alloy powder mass percent compositions include, but are not limited to: Cr 14.9-17.1 wt.%, Co 12.1-13.5 wt.%, Mo 3.2-4.1 wt.%, W 4.1-5.0 wt.%, Nb 1.9-2.7 wt.%, C 0.045-0.065 wt.%, balance Ni.

[0021] In some embodiments, the low melting alloy powder composition is Ni-Cr-Al-Ta-Ti, in mass percent: Cr 11.7-12.5 wt.%, Al 6.2-7.9 wt.%, Ta 8.2-9.5 wt.%, Ti 14.8-19.8 wt.%, balance Ni. Selected high melting alloy powder mass percent compositions include, but are not limited to: Cr 11.9-13.1 wt.%, Co 12.8-11.5 wt.%, Mo 3.2-5.1 wt.%, W 2.1-3.1 wt.%, Al 2.9-3.1 wt.%, Nb 0.9-1.7 wt.%, C 0.041-0.051 wt.%, balance Ni.

[0022] In some embodiments, the low melting alloy powder composition is Ni-Ti, in mass percent: Ti 68.0-72.0 wt.%, balance Ni. Selected high melting alloy powder mass percent compositions include, but are not limited to: Cr 16.5-17.5 wt.%, Co 13.5-14.5 wt.%, Mo 4.2-4.8 wt.%, W 4.2-4.8 wt.%, Al 2.3-2.5 wt.%, Nb 2.6-3.0 wt.%, C 0.055-0.085 wt.%, balance Ni.

[0023] In some embodiments, the low-melting alloy powder is Ni-Al, with the mass percentage of Al being 90.0-92.0 wt.%, and the balance being Ni. The selected high-melting alloy powder mass percentage components include, but are not limited to, Cr 9.5-11.5 wt.%, Co 11.0-13.0 wt.%, Mo 2.0-3.0 wt.%, Nb 0.5-1.0 wt.%, C 0.021-0.035 wt.%, and the balance being Ni.

[0024] The technical solutions provided by the embodiments of the present disclosure can include the following beneficial effects:

[0025] 1. The present disclosure proposes a completely new process method for avoiding the generation of original powder particle boundary defects in the manufacture of high-performance powder superalloys by using a hot isostatic pressing process, without the need for additional processing steps and additional chemical component additions, thereby reducing process costs, improving production efficiency, and realizing the low-cost short-process preparation of high-performance powder superalloys. This technology can be used to prepare nickel-based powder superalloys, and can also be used to prepare other high-temperature alloys.

[0026] 2. The physical process for preparing the powder superalloy in the present disclosure is an isothermal solidification process. In the sintering process, the sintering temperature is higher than the melting point of the low-melting alloy powder, so that the low-melting alloy powder is melted to form a liquid phase, and the sintering temperature is lower than the melting point of the high-melting alloy powder, so that the high-melting alloy powder is in the form of solid particles. The liquid phase wets the surface of the high-melting alloy powder particles, the components between the liquid phase and the solid phase interdiffuse, the surface layer of the solid phase powder is slightly eroded, the liquid phase begins to isothermally solidify, and the rapid manufacture of an equiaxed crystal powder superalloy with uniform organization and small grain size is realized. In this process, there are no physical conditions for the formation of original powder particle boundaries, and this defect is completely avoided. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0028] FIG. 1 is a schematic diagram of the process principle of the powder superalloy prepared by the present disclosure without original powder particle boundary defects.

[0029] FIG. 2 is a comparison diagram of the scanning electron microscope photos of the powder superalloy prepared in Example 1 and the powder superalloy with original particle boundaries.

[0030] FIG. 3 is a comparison diagram of the optical microscope photos of the powder superalloy prepared in Example 2 and the powder superalloy with original particle boundaries.

[0031] FIG. 4 is a comparison diagram of the optical microscope photos of the powder superalloy prepared in Example 3 and the powder superalloy with original particle boundaries. Detailed Implementation

[0032] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure.

[0033] The present disclosure is described in detail below with reference to the accompanying drawings and embodiments, but the scope of protection of the present disclosure is not limited thereto.

[0034] In related technologies, thermoplastic processing can effectively eliminate the original powder particle boundary defects in powder superalloys, but it increases the process cost and prolongs the process flow. Furthermore, other methods to avoid or eliminate the original powder particle boundaries are still in the experimental stage, and their process results are unsatisfactory. Therefore, there is an urgent need to develop a short-process method suitable for industrial production to prepare powder superalloys without original powder particle boundary defects.

[0035] To address the aforementioned technical problems, this disclosure provides a method for manufacturing powder superalloys. The method involves preparing sintering raw materials, which utilize two pre-alloyed powders with different melting points: a low-melting-point alloy powder and a high-melting-point alloy powder. The combined composition of the two pre-alloyed powders is completely identical to that of the target powder superalloy. During sintering, the sintering temperature is higher than the melting point of the low-melting-point alloy powder to melt it into a liquid phase, while the sintering temperature is lower than the melting point of the high-melting-point alloy powder to ensure that the high-melting-point alloy powder remains as solid particles. The liquid phase formed by the melting of the low-melting-point alloy powder thoroughly wets the particle surface, removes impurities adhering to the particle surface, and undergoes solid-liquid interdiffusion with the high-melting-point alloy powder, achieving isothermal solidification and ultimately forming a high-performance powder superalloy without the original powder particle boundaries.

[0036] It should be noted that the constituent elements of low-melting-point alloy powder and high-melting-point alloy powder can be completely different or partially the same, as long as the overall melting point of low-melting-point alloy powder is lower than the sintering temperature and the overall melting point of high-melting-point alloy powder is higher than the sintering temperature.

[0037] Original particle boundary defects refer to a type of defect in powder superalloys prepared by hot isostatic pressing using solid-state sintering. It refers to the clearly discernible original powder shape and initial interfaces between the powder particles when observed under a microscope. These defects typically present as a network of circular or near-circular particles, usually containing continuous or semi-continuous carbon oxides. See Figure 2(b), Figure 3(d), and Figure 4(f).

[0038] No original particle boundary refers to that no round or nearly round boundary can be observed in the sintered sample by microscope, but a network composed of nearly hexagonal grain boundaries is presented. It can be referred to the (a) part of FIG. 2, the (c) part of FIG. 3 and the (e) part of FIG. 4.

[0039] In the embodiments of the present disclosure, the above-mentioned scheme can be used for preparing a nickel-based powder superalloy, and can also be used for preparing other superalloys.

[0040] The physical process for preparing the powder superalloy in the present disclosure is an isothermal solidification process. In the sintering process, the sintering temperature is higher than the melting point of the low-melting alloy powder, so that the low-melting alloy powder is melted to form a liquid phase, and the sintering temperature is lower than the melting point of the high-melting alloy powder, so that the high-melting alloy powder is in a solid phase. The liquid phase wets the surface of the high-melting alloy powder particles, the components between the liquid phase and the solid phase interdiffuse, the surface layer of the solid phase powder is slightly corroded, the liquid phase begins to isothermally solidify, and the uniform organization and fine-grained equiaxed crystal powder superalloy are realized. In this process, the physical conditions for forming the original powder particle boundary are not met, and this defect is completely avoided. The present disclosure proposes a new process method for avoiding the original powder particle boundary defect of the high-performance powder superalloy manufactured by using the hot isostatic pressing process, and does not need additional processing steps and additional chemical component addition, which can reduce the process cost, improve the production efficiency, and realize the low-cost short-process preparation of the high-performance powder superalloy.

[0041] The present disclosure is a method for manufacturing a high-performance powder superalloy with low cost and short process, which avoids the original powder particle boundary defect of the high-performance powder superalloy manufactured by using the hot isostatic pressing process, and realizes the short-process manufacturing. As shown in FIG. 1, the specific process of the present embodiment includes the following steps:

[0042] 1) According to the target powder superalloy composition, design and prepare low-melting alloy powder and high-melting alloy powder, the particle size of the low-melting alloy powder and the high-melting alloy powder is less than or equal to 100 microns, and the shape of the low-melting alloy powder and the high-melting alloy powder is nearly spherical powder;

[0043] 2) According to the required mass ratio of the target powder superalloy composition, weigh the low-melting alloy powder and the high-melting alloy powder, ball mill and mix uniformly, the ball mill speed is 120-200 r / min, and the ball milling time is 120-150 min, to obtain the sintering raw material;

[0044] 3) Fill the sintering raw material in a low-carbon steel jacket, and after degassing at a high temperature of 180-300℃, perform vacuum sealing;

[0045] 4) Put the package into the hot isostatic pressing equipment, and perform hot isostatic pressing sintering by synchronously increasing temperature and pressure or by increasing temperature first and then increasing pressure; the sintering temperature is 1150-1300℃, the holding time is 2-4h, and the sintering pressure is 120-150MPa;

[0046] 5) After the hot isostatic pressing process is completed, the target powder superalloy is taken out when the furnace temperature cools to room temperature.

[0047] In some embodiments, two pre-alloy powders with different melting points are used, wherein the low-melting alloy powder is a binary, ternary or multi-element alloy powder of target powder superalloy elements (Ni, Cr, Co, Ti, Al, Ta), with a melting point lower than 1250℃, and a volume fraction of 10%-50% in the sintered raw material; and the high-melting alloy powder is composed of the target powder superalloy elements, and the composition of the high-melting alloy powder is designed according to the requirement that the sum of the composition of the high-melting alloy powder and the composition of the low-melting alloy powder is the composition of the target powder superalloy.

[0048] In some embodiments, the composition of the low-melting alloy powder is Ni-Al-Ta-Ti, with mass percentages of Ta 14.5-16.5wt.%, Al 6.0-7.0wt.%, Ti 14.8-15.8wt.%, and the balance being Ni; and the composition of the high-melting alloy powder matched with the composition of the low-melting alloy powder is Cr 15.5-16.5wt.%, Co 14.0-15.0wt.%, Mo 5.0-5.5wt.%, W 5.0-5.5wt.%, Nb 2.6-3.0wt.%, C 0.025-0.045wt.%, and the balance being Ni.

[0049] In some embodiments, the composition of the low-melting alloy powder is Ni-Cr-Ta-Ti, with mass percentages of Cr 11.7-12.5wt.%, Ta 3.2-4.5wt.%, Ti 9.2-10.9wt.%, and the balance being Ni; and the composition of the high-melting alloy powder matched with the composition of the low-melting alloy powder is Cr 11.5-13.5wt.%, Co 9.0-11.0wt.%, Mo 1.0-3.5wt.%, W 9.0-10.5wt.%, Nb 0.6-1.0wt.%, C 0.025-0.045wt.%, and the balance being Ni.

[0050] In some embodiments, the low melting alloy powder composition is Ni-Cr-Co-Al-Ti, with mass percentages of Cr 15.7-16.5 wt.%, Co 8.2-9.5 wt.%, Al 6.2-7.9 wt.%, Ti 14.8-19.8 wt.%, and the balance being Ni; and the high melting alloy powder composition to be combined with the low melting alloy powder composition is Cr 14.9-17.1 wt.%, Co 12.1-13.5 wt.%, Mo 3.2-4.1 wt.%, W 4.1-5.0 wt.%, Al 1.9-2.1 wt.%, Nb 1.9-2.7 wt.%, C 0.045-0.065 wt.%, and the balance being Ni.

[0051] In some embodiments, the low melting alloy powder composition is Ni-Cr-Co-Al-Ti, with mass percentages of Cr 15.7-16.5 wt.%, Co 8.2-9.5 wt.%, Al 6.2-7.9 wt.%, Ti 14.8-19.8 wt.%, and the balance being Ni; and the high melting alloy powder composition to be combined with the low melting alloy powder composition is Cr 14.9-17.1 wt.%, Co 12.1-13.5 wt.%, Mo 3.2-4.1 wt.%, W 4.1-5.0 wt.%, Al 1.9-2.1 wt.%, Nb 1.9-2.7 wt.%, C 0.045-0.065 wt.%, and the balance being Ni.

[0052] In some embodiments, the low melting alloy powder composition is Ni-Cr-Co-Al-Ti, with mass percentages of Cr 15.7-16.5 wt.%, Co 8.2-9.5 wt.%, Al 6.2-7.9 wt.%, Ti 14.8-19.8 wt.%, and the balance being Ni; and the high melting alloy powder composition to be combined with the low melting alloy powder composition is Cr 14.9-17.1 wt.%, Co 12.1-13.5 wt.%, Mo 3.2-4.1 wt.%, W 4.1-5.0 wt.%, Al 1.9-2.1 wt.%, Nb 1.9-2.7 wt.%, C 0.045-0.065 wt.%, and the balance being Ni.

[0053] In some embodiments, the low melting alloy powder composition is Ni-Cr-Co-Al-Ti, with mass percentages of Cr 15.7-16.5 wt.%, Co 8.2-9.5 wt.%, Al 6.2-7.9 wt.%, Ti 14.8-19.8 wt.%, and the balance being Ni; and the high melting alloy powder composition to be combined with the low melting alloy powder composition is Cr 14.9-17.1 wt.%, Co 12.1-13.5 wt.%, Mo 3.2-4.1 wt.%, W 4.1-5.0 wt.%, Al 1.9-2.1 wt.%, Nb 1.9-2.7 wt.%, C 0.045-0.065 wt.%, and the balance being Ni.

[0054] In some embodiments, the low-melting alloy powder component is Ni-Ti, with mass percentages of: Ti 68.0-72.0 wt.%, and the balance being Ni; and the high-melting alloy powder component matched with the low-melting alloy powder component is Cr 16.5-17.5 wt.%, Co 13.5-14.5 wt.%, Mo 4.2-4.8 wt.%, W 4.2-4.8 wt.%, Al 2.3-2.5 wt.%, Nb 2.6-3.0 wt.%, C 0.055-0.085 wt.%, and the balance being Ni.

[0055] Example 1

[0056] This example is to prepare a powder superalloy FGH4096 using the process of the present disclosure, with the powder superalloy component having mass percentages of: Cr 15.5-16.5 wt.%, Co 12.5-13.5 wt.%, W 3.8-4.2 wt.%, Mo 3.8-4.2 wt.%, Al 2.0-2.4 wt.%, Ti 3.5-3.9 wt.%, Nb 0.6-0.8 wt.%, C 0.045-0.060 wt.%, and the balance being Ni.

[0057] The specific process is as follows:

[0058] 1) Prepare low-melting alloy powder and high-melting alloy powder, with the low-melting alloy powder having a component with mass percentages of: Ti 68.0-72.0 wt.%, and the balance being Ni; and the high-melting alloy powder having a component with mass percentages of: Cr 16.5-17.5 wt.%, Co 13.5-14.5 wt.%, Mo 4.2-4.8 wt.%, W 4.2-4.8 wt.%, Al 2.3-2.5 wt.%, Nb 2.6-3.0 wt.%, C 0.045-0.065 wt.%; the particle size of the low-melting alloy powder and the high-melting alloy powder is less than or equal to 100 microns, and the shape of the low-melting alloy powder and the high-melting alloy powder is near-spherical powder.

[0059] 2) Weigh the two powders and mix them uniformly by ball milling at a speed of 150 r / min for 120 min to obtain a sintering raw material, wherein the volume fraction of the low-melting alloy powder is 8%.

[0060] 3) Fill the sintering raw material in a low-carbon steel jacket, and after degassing at a high temperature of 250°C, perform vacuum sealing.

[0061] 4) Put the package into the hot isostatic pressing device, and simultaneously increase the temperature and pressure or first increase the temperature and then increase the pressure to perform hot isostatic pressing sintering. The sintering temperature is 1180°C, which is higher than the melting point of the low-melting alloy powder and lower than the melting point of the high-melting alloy powder, the holding time is 4h, and the sintering pressure is 120MPa.

[0062] 5) After the hot isostatic pressing process is completed, the target powder superalloy is taken out when the furnace temperature cools to room temperature.

[0063] The prepared powder superalloy is cut open, and the section is polished and polished and etched for microstructure observation. No original powder particle boundary defect is found. As shown in FIG. 2, in which part (a) of FIG. 2 shows that the prepared powder superalloy cannot be observed to have circular or nearly circular boundaries, and presents a network composed of nearly hexagonal grain boundaries, i.e. a microstructure without original particle boundaries. Part (b) of FIG. 2 shows that the powder superalloy has a network composed of circular or nearly circular shapes, i.e. a microstructure with original particle boundaries.

[0064] Example 2

[0065] This example is another powder superalloy prepared by the process of the present disclosure. The mass fraction of the components of the powder superalloy is: Cr 15.5-16.5wt.%, Co 12.5-13.5wt.%, W 3.8-4.2wt.%, Mo 3.8-4.2wt.%, Al 2.0-2.4wt.%, Ta 3.5-4.0wt.%, Ti 3.5-3.9wt.%, Nb 0.6-0.8wt.%, C 0.045-0.060wt.%, and the balance is Ni and unavoidable impurities.

[0066] The specific process is as follows:

[0067] 1) Prepare low-melting alloy powder and high-melting alloy powder. The mass fraction of the components of the low-melting alloy powder is: Ta 15.5-16.5wt.%, Al 6.0-7.0wt.%, Ti 14.8-15.8wt.%, and the balance is Ni. The mass fraction of the components of the high-melting alloy powder is: Cr 15.5-16.5wt.%, Co 14.0-15.0wt.%, Mo 5.0-5.5wt.%, W 5.0-5.5wt.%, Nb 2.6-3.0wt.%, C 0.045-0.065wt.%, and the balance is Ni and unavoidable impurities. The particle size of the low-melting alloy powder and the high-melting alloy powder is less than or equal to 100 microns, and the shape of the low-melting alloy powder and the high-melting alloy powder is near-spherical powder.

[0068] 2) Take two kinds of powder and mix them evenly by ball milling at a speed of 100 r / min for 150 min to obtain the sintering raw material, wherein the volume fraction of the low-melting alloy powder is 30%.

[0069] 3) Fill the sintering raw material in a low-carbon steel jacket, and perform vacuum sealing after degassing at a high temperature of 300℃.

[0070] 4) Place the jacket in a hot isostatic pressing device, and perform hot isostatic pressing sintering by simultaneously increasing the temperature and pressure or first increasing the temperature and then increasing the pressure. The sintering temperature is 1180℃, which is higher than the melting point of the low-melting alloy powder and lower than the melting point of the high-melting alloy powder, the holding time is 4 h, and the sintering pressure is 150 MPa.

[0071] 5) After the hot isostatic pressing process is completed, the target powder superalloy is taken out when the furnace temperature cools to room temperature.

[0072] The prepared powder superalloy is cut open, and the cross section is polished and etched for observation. No original powder particle boundary defects are found. As shown in FIG. 3, part (c) of FIG. 3 shows that the prepared powder superalloy cannot be observed to have circular or nearly circular boundaries, and presents a network composed of nearly hexagonal grain boundaries, i.e., a microstructure without original particle boundaries. Part (d) of FIG. 3 shows that the powder superalloy has a network composed of circular or nearly circular shapes, i.e., a microstructure with original particle boundaries.

[0073] Example 3

[0074] This example is another powder superalloy prepared by the process of the present disclosure. The mass fraction of the components of the powder superalloy is: Cr 9.5-11.5wt.%, Co 12.5-13.5wt.%, Mo 2.5-3.5wt.%, Al 6.0-7.0wt.%, Nb 0.6-0.8wt.%, C 0.045-0.060wt.%, and the balance is Ni.

[0075] The specific process is as follows:

[0076] 1) Prepare low-melting alloy powder and high-melting alloy powder. The mass fraction of the components of the low-melting alloy powder is: Al 90.0-92.0wt.%, and the balance is Ni. The mass fraction of the components of the high-melting alloy powder is: Cr 9.5-11.5wt.%, Co 11.0-13.0wt.%, Mo 2.0-3.0wt.%, Nb 0.5-1.0wt.%, C 0.045-0.065wt.%, and the balance is Ni and unavoidable impurities. The particle size of the low-melting alloy powder and the high-melting alloy powder is less than or equal to 100 microns, and the shape of the low-melting alloy powder and the high-melting alloy powder is nearly spherical powder.

[0077] 2) Two kinds of powder are weighed and mixed uniformly by ball milling at a speed of 80 r / min for 150 min to obtain the sintering raw material, wherein the volume fraction of the low-melting alloy powder is 15%.

[0078] 3) The sintering raw material is filled in a low-carbon steel can, degassed at a high temperature of 300 DEG C, and then vacuum sealed.

[0079] 4) The prepared can is placed in a hot isostatic pressing device, and hot isostatic pressing sintering is performed by synchronous temperature and pressure rising or temperature rising followed by pressure rising. The sintering temperature is 1200 DEG C, which is higher than the melting point of the low-melting alloy powder and lower than the melting point of the high-melting alloy powder, the holding time is 2 h, and the sintering pressure is 130 MPa.

[0080] 5) After the hot isostatic pressing process is completed, the target powder superalloy is taken out when the furnace temperature cools to room temperature.

[0081] The prepared powder superalloy is cut open, polished and etched, and then microstructure observation is performed. No original powder particle boundary defect is found. As shown in FIG. 4, in the (e) part of FIG. 4, it is shown that the prepared powder superalloy cannot be observed to have a circular or nearly circular boundary, and presents a network composed of nearly hexagonal grain boundaries, i.e. a microstructure without original particle boundary. In the (f) part of FIG. 4, it is shown that the powder superalloy has a network composed of circular or nearly circular shapes, i.e. a microstructure with original particle boundary.

Claims

1. A method of manufacturing a powdered high temperature alloy, characterized by, The method comprises: Preparation of sintering raw material, which uses two pre-alloy powders with different melting points, the two pre-alloy powders include low-melting alloy powder and high-melting alloy powder, and the total composition of the two pre-alloy powders is completely identical to the composition of the target powder superalloy; During the sintering process, the sintering temperature is higher than the melting point of the low-melting alloy powder to make the low-melting alloy powder melt to form a liquid phase, and the sintering temperature is lower than the melting point of the high-melting alloy powder to ensure that the high-melting alloy powder is in the form of solid-phase particles; the liquid phase formed by the melting of the low-melting alloy powder sufficiently wets the surface of the high-melting alloy powder and undergoes solid-liquid interdiffusion with the high-melting alloy powder to realize isothermal solidification, and finally forms the powder superalloy.

2. The method of claim 1, wherein The method comprises the following process steps: 1) According to the composition of the target powder superalloy, prepare low-melting alloy powder and high-melting alloy powder, the particle size of the low-melting alloy powder and the high-melting alloy powder is less than or equal to 100 microns, and the shape of the low-melting alloy powder and the high-melting alloy powder is near-spherical powder; 2) According to the required mass ratio of the composition of the target powder superalloy, weigh the low-melting alloy powder and the high-melting alloy powder, ball mill to mix uniformly, the rotation speed of the ball mill is 120-200 r / min, and the ball milling time is 120-150 min to obtain the sintering raw material; 3) Fill the sintering raw material in a low-carbon steel jacket, perform high-temperature degassing at 180-300 ℃, and then perform vacuum sealing; 4) Place the jacket in a hot isostatic pressing device, simultaneously increase the temperature and pressure or first increase the temperature and then increase the pressure to perform hot isostatic pressing sintering; the sintering temperature is 1150-1300 ℃, the holding time is 2-4 h, and the sintering pressure is 120-150 MPa; 5) After the hot isostatic pressing process is completed, take out the target powder superalloy when the furnace temperature cools to room temperature.

3. The method of manufacturing a powdered high temperature alloy according to claim 1 or 2, characterized in that, In the two pre-alloy powders with different melting points, the low-melting alloy powder is a binary, ternary or multi-element alloy powder of the elements Ni, Cr, Co, Ti, Al and Ta in the target powder superalloy, and the melting point is lower than 1250 ℃; the volume fraction of the low-melting alloy powder in the sintering raw material is 10%-50%; and the composition of the high-melting alloy powder is determined according to the composition of the target powder superalloy, and the composition of the high-melting alloy powder is designed according to the requirement that the total composition of the high-melting alloy powder composition and the low-melting alloy powder composition is the composition of the target powder superalloy.

4. The method of claim 3, wherein the powder superalloy is produced by a process comprising: The composition of the low-melting alloy powder is Ni-Al-Ta-Ti, and the mass percentage is: Ta 14.5-16.5 wt.%, Al 6.0-7.0 wt.%, Ti 14.8-15.8 wt.%, and the balance is Ni; and the composition of the high-melting alloy powder matched with the composition of the low-melting alloy powder is Cr 15.5-16.5 wt.%, Co 14.0-15.0 wt.%, Mo 5.0-5.5 wt.%, W 5.0-5.5 wt.%, Nb 2.6-3.0 wt.%, C 0.025-0.045 wt.%, and the balance is Ni.

5. The method of claim 3, wherein the powder superalloy is produced by the steps of: The low-melting alloy powder component is Ni-Cr-Ta-Ti, with mass percentage of Cr 11.7-12.5wt.%, Ta 3.2-4.5wt.%, Ti 9.2-10.9wt.%, and the balance being Ni; and the high-melting alloy powder component matched with the low-melting alloy powder component is Cr 11.5-13.5wt.%, Co 9.0-11.0wt.%, Mo 1.0-3.5wt.%, W 9.0-10.5wt.%, Nb 0.6-1.0wt.%, C 0.025-0.045wt.%, and the balance being Ni.

6. The method of claim 3, wherein the powder superalloy is produced by the steps of: The low-melting alloy powder component is Ni-Cr-Ta-Ti, with mass percentage of Cr 11.7-12.5wt.%, Ta 3.2-4.5wt.%, Ti 9.2-10.9wt.%, and the balance being Ni; and the high-melting alloy powder component matched with the low-melting alloy powder component is Cr 11.5-13.5wt.%, Co 9.0-11.0wt.%, Mo 1.0-3.5wt.%, W 9.0-10.5wt.%, Nb 0.6-1.0wt.%, C 0.025-0.045wt.%, and the balance being Ni.

7. The method of claim 3, wherein the powder superalloy is produced by the steps of: The low-melting alloy powder component is Ni-Cr-Ta-Ti, with mass percentage of Cr 11.7-12.5wt.%, Ta 3.2-4.5wt.%, Ti 9.2-10.9wt.%, and the balance being Ni; and the high-melting alloy powder component matched with the low-melting alloy powder component is Cr 11.5-13.5wt.%, Co 9.0-11.0wt.%, Mo 1.0-3.5wt.%, W 9.0-10.5wt.%, Nb 0.6-1.0wt.%, C 0.025-0.045wt.%, and the balance being Ni.

8. The method of claim 3, wherein the powder superalloy is produced by the steps of: The low-melting alloy powder component is Ni-Cr-Ta-Ti, with mass percentage of Cr 11.7-12.5wt.%, Ta 3.2-4.5wt.%, Ti 9.2-10.9wt.%, and the balance being Ni; and the high-melting alloy powder component matched with the low-melting alloy powder component is Cr 11.5-13.5wt.%, Co 9.0-11.0wt.%, Mo 1.0-3.5wt.%, W 9.0-10.5wt.%, Nb 0.6-1.0wt.%, C 0.025-0.045wt.%, and the balance being Ni.

9. The method of claim 3, wherein the powder superalloy is produced by the steps of: The low-melting alloy powder component is Ni-Cr-Al-Ta-Ti, with mass percentages of Cr 11.7-12.5 wt.%, Al 6.2-7.9 wt.%, Ta 8.2-9.5 wt.%, Ti 14.8-19.8 wt.%, and the balance being Ni; and the high-melting alloy powder component matched with the low-melting alloy powder component is Cr 11.9-13.1 wt.%, Co 12.8-11.5 wt.%, Mo 3.2-4.1 wt.%, W 2.1-5.1 wt.%, Al 2.9-3.1 wt.%, Nb 0.9-1.7 wt.%, C 0.041-0.051 wt.%, and the balance being Ni.

10. The method of claim 3, wherein the powder superalloy is produced by the steps of: The low-melting alloy powder component is Ni-Ti, with mass percentages of Ti 68.0-72.0 wt.%, and the balance being Ni; and the high-melting alloy powder component matched with the low-melting alloy powder component is Cr 16.5-17.5 wt.%, Co 13.5-14.5 wt.%, Mo 4.2-4.8 wt.%, W 4.2-4.8 wt.%, Al 2.3-2.5 wt.%, Nb 2.6-3.0 wt.%, C 0.055-0.085 wt.%, and the balance being Ni.

Images