CN115070044A

CN115070044A - GH4169 and TA19 same-material and different-material multistage rotor assembly and preparation method thereof

Info

Publication number: CN115070044A
Application number: CN202110261166.9A
Authority: CN
Inventors: 张露; 张国栋; 赵诗棋; 史栋刚; 南洋
Original assignee: AECC Commercial Aircraft Engine Co Ltd
Current assignee: AECC Commercial Aircraft Engine Co Ltd
Priority date: 2021-03-10
Filing date: 2021-03-10
Publication date: 2022-09-20
Anticipated expiration: 2041-03-10
Also published as: CN115070044B

Abstract

The invention provides a GH4169 and TA19 same-material and dissimilar-material multi-stage rotor assembly and a hot isostatic pressing near-net-shape forming preparation method thereof, wherein the multi-stage rotor assembly is divided into two alloy areas, the different alloy areas are compacted by a cold pressing method when powder is filled in the different alloy areas before hot isostatic pressing, and after the hot isostatic pressing, the two different alloy areas and a dissimilar-material combination area are subjected to partitioned solid solution heat treatment and aging treatment, so that the prepared rotor assembly can be freely combined in the structural form and is not limited by the number of assembly stages; the final rotor assembly is formed by one-time hot isostatic pressing, the uniformity of the joint surface structure is good, the overall performance of the multistage rotor is high, the lean manufacturing of the GH4169 and TA19 alloy same-kind and dissimilar-kind material multistage rotor assembly is realized, and the use performance of the rotor is improved; in addition, the method adopts cold press molding to the pre-pressing body, thereby not only avoiding powder mixing, but also reducing the preparation cost of large-scale welding equipment, shortening the preparation process flow and reducing the preparation difficulty.

Description

GH4169 and TA19 same-material and different-material multistage rotor assembly and preparation method thereof

Technical Field

The invention relates to a manufacturing technology of an aircraft engine rotor, in particular to a dissimilar alloy multistage rotor assembly and a preparation method thereof.

Background

The rotor of the aircraft engine operates at high temperature, high pressure and high rotating speed, and parts bear thermal load, pneumatic load, centrifugal load and the like, so that higher requirements are provided for the comprehensive performance of the rotor assembly. On one hand, as the thrust-weight ratio of the engine is increased, the service temperature of the disc part is also continuously increased, so that the powder high-temperature alloy GH4169 alloy and the low-cost TA19 alloy are gradually applied to aeroengine disc rotating parts, such as a high-pressure compressor disc, a high-pressure turbine disc and the like. On the other hand, in order to reduce the structural weight and enhance the structural reliability, the aero-engine rotor is developed to be light and integrated, and the rotor made of different material combinations also causes the problem of integrated connection.

In the aspect of multi-stage rotor integration, the most widely applied process at present is to realize the connection of the multi-stage rotor assembly by welding. In the selection of the welding method, TA19 and GH4169 have great differences in material composition and structure performance, so that the connection cannot be directly performed by adopting a welding process, and the connection mode between the titanium alloy and the high-temperature alloy rotor assembly is bolt connection at present. However, the bolted connection increases the weight of the rotor assembly and reduces the reliability of the connection, thereby increasing the overall weight of the engine and reducing engine efficiency.

In recent years, hot isostatic pressing near net shape technology has matured, and the technology combines hot isostatic pressing densification and near net shape process control to provide a hot blank with required shape, size and structure for subsequent machining, isothermal forging or heat treatment.

The hot isostatic pressing near net shape process has the following advantages over the welding process of a typical rotor assembly:

1) uniform structure and high mechanical property: the hot isostatic pressing near-net forming part has high density and uniform components, and no macroscopic component segregation exists in the structure, so the comprehensive mechanical property is excellent and can reach the level of a forging piece, and is higher than the mechanical property of a welding joint.

2) And (3) reducing machining procedures: compared with the method of machining by adopting forgings, the hot isostatic pressing near-net-shape forming part has the advantages that the technological process is relatively simple, only the assembly is subjected to combined machining, and the machining procedures of the rotor assembly before welding are reduced.

3) The equipment is simple: the hot isostatic pressing near-net forming technology mainly utilizes hot isostatic pressing equipment, avoids the use of large welding equipment, particularly large inertia friction welding equipment, and solves the problem of resource shortage of the welding equipment.

4) The method is applicable to various structures: various structures, particularly complex structures, can be prepared by hot isostatic pressing near net shape processes.

5) The manufacturing cost is low: the hot isostatic pressing near-net-shape part has high material utilization rate, relatively simple process and short process period, and reduces the manufacturing cost.

The hot isostatic pressing near-net forming technology is adopted to prepare the GH4169 and TA19 alloy same-kind and dissimilar-kind material multistage rotor assembly, two kinds of alloy powder of GH4169 and TA19 are adopted, but when the powder is combined in a powder state, the component distribution of the mixed powder and the mixed powder of the GH4169 and the TA19 at an interface is difficult to control, and the components, the structure and the performance at the joint surface cannot be guaranteed. In addition, the heat treatment schedules of the GH4169 and TA19 alloys are also different, and higher requirements are placed on the selection of hot isostatic pressing process parameters for the whole assembly.

Accordingly, improvements in methods of making multi-stage rotor assemblies to address the above problems are needed for GH4169 and TA19 alloy homogeneous and heterogeneous multi-stage rotor assemblies.

Disclosure of Invention

The invention aims to solve the technical problem that aiming at the defects of the prior art, the invention provides the preparation method of the GH4169 and TA19 alloy same-material and different-material multi-stage rotor assembly, so that the uniformity of the joint surface structure between the multi-stage rotor parts is good, the overall performance is high, and the preparation cost is relatively low.

In order to solve the above problems, according to a first aspect of the present invention, there is provided a method of making a GH4169 and TA19 homogeneous, dissimilar material multi-stage rotor assembly having a first disk body region of a GH4169 alloy having at least one rotor section and a second disk body region of a TA19 alloy having at least one rotor section, the method comprising the steps of:

designing a preform for each rotor section of the rotor assembly;

preparing a sheath of each level of the prefabricated body, wherein a sheath interface is arranged at the position, connected with an adjacent sheath, of each level of the sheath;

welding the sheath and a preceding sheath at a sheath interface from the last sheath, filling alloy powder into a rear sheath of two to-be-welded sheaths before welding, performing cold pressing compaction, and filling alloy powder into a first sheath before welding the first sheath, and performing cold pressing compaction, so as to obtain a rotor assembly preform with each stage connected in sequence;

carrying out hot isostatic pressing treatment on the rotor assembly preform at the temperature of 1020-1070 ℃, the pressure of 130-170 MPa and the time of 1.5-3 hours to obtain a rotor assembly blank;

removing the sheath from the rotor assembly blank;

and carrying out heat treatment on the first disc body area and the second disc body area of the rotor assembly blank, wherein the combination area of the first disc body area and the second disc body area and the first disc body area are subjected to heat treatment together, so that a rotor assembly is obtained.

Preferably, the at least one rotor part of the first disk body area is arranged continuously, and the at least one rotor part of the second disk body area is arranged continuously.

Preferably, the first disk body region is located at a preceding stage of the second disk body region.

Preferably, the second disk body region is located at a preceding stage of the first disk body region.

Preferably, the first disk body section includes a two-stage rotor portion, and the second disk body section includes a one-stage rotor portion.

Preferably, the final stage of the sheath is filled with alloy powder and cold compacted, and the first stage of the sheath is filled with alloy powder and cold compacted.

Preferably, the heat treatment includes solution treatment, and the solution treatment performed on the first disc body area and the bonding area is air cooling after heat preservation for 1 to 3 hours at a temperature ranging from 950 to 980 ℃, and the solution treatment performed on the second disc body area is air cooling after heat preservation for 0.5 to 2.5 hours at a temperature ranging from 960 to 990 ℃.

Preferably, the heat treatment still includes aging treatment, aging treatment is in go on after the solution treatment, to first disk body district with aging treatment that the bonding region goes on keeps warm for 7 hours to 9 hours at temperature 705 ℃ to 735 ℃ within range, keeps warm for 7 hours to 9 hours at temperature 605 ℃ to 635 ℃ within range after, and the while is to the aging treatment that the second disk body district goes on keeps warm for 4 hours to 10 hours after temperature 585 ℃ to 620 ℃ within range and carries out the air cooling.

Preferably, the method further comprises the following steps after the heat treatment step:

carrying out flaw detection on the rotor assembly blank; and

and carrying out combined machining and stress relief treatment on the rotor assembly blank.

According to a second aspect of the present invention there is provided a GH4169 and TA19 homogeneous, heterogeneous material multi-stage rotor assembly having a first disc region of GH4169 alloy having at least one rotor section and a second disc region of TA19 alloy having at least one rotor section, the rotor assembly being prepared by a method as hereinbefore described.

According to the invention, the multistage rotor assembly is divided into two alloy areas, the different alloy areas are compacted by a cold pressing method when being filled with powder before hot isostatic pressing, and the two different alloy areas and the dissimilar material combining area are subjected to partitioned heat treatment after the hot isostatic pressing, so that the problems of how to combine powder with two components of GH4169 and TA19 at an interface and non-uniformity of heat treatment systems of the two materials are effectively solved. Compared with the prior art, the hot isostatic pressing net-approximate-forming method of the multistage engine rotor is adopted, and the prepared rotor can be freely combined in the structural form and is not limited by the number of stages of components; the final rotor assembly is formed by one-time hot isostatic pressing, the uniformity of a joint surface structure is good, the overall performance of the multi-stage rotor is high, the tensile performance test result of the joint of TA19+ GH4169 is that sigma b is more than or equal to 900MPa and can reach the performance level of a TA19+ GH4169 welding joint, the tensile performance test result of the TA19 alloy is that sigma b is more than or equal to 900MPa and can reach the performance level of a forging piece of TA19 alloy, the tensile performance test result of the GH4169 alloy is that sigma b is more than or equal to 1300MPa and can reach the performance level of the forging piece of the GH4169 alloy, the lean manufacturing of the GH4169 and TA19 alloy multi-stage rotor assemblies made of the same and different materials is realized, and the use performance of the rotor is improved; in addition, the method adopts cold press molding to the pre-pressing body, thereby not only avoiding powder mixing, but also reducing the preparation cost of large-scale welding equipment, shortening the preparation process flow and reducing the preparation difficulty.

Drawings

The foregoing summary, as well as the following detailed description of the invention, will be better understood when read in conjunction with the appended drawings. It is to be noted that the appended drawings are intended as examples of the claimed invention. In the drawings, like reference characters designate the same or similar elements.

FIG. 1 is a schematic view of a multi-stage rotor assembly according to an embodiment of the present invention;

FIG. 2 is a schematic illustration of a preform design for the multi-stage rotor assembly shown in FIG. 1;

FIG. 3 is a jacket design schematic of the multi-stage rotor assembly of FIG. 1;

FIG. 4 is a schematic illustration of preform preparation of the multi-stage rotor assembly shown in FIG. 1;

fig. 5 is a schematic view of the multi-stage rotor assembly blank of fig. 1.

The reference numbers illustrate:

1: three-stage rotor assembly

1 a: a first disc area

1 b: second disk body area

1-1: first stage rotor section

1-2: second stage rotor section

1-3: third stage rotor section

2-1: first stage preform

2-2: second-stage preform

2-3: third-stage preform

3-1: first-level jacket

3-2: second-level jacket

3-3: third-level sheath

3-4: sheath interface

4-1: GH4169 alloy powder

4-2: TA19 alloy powder

5: amount of reserve

6: rotor assembly blank

6-1: first stage blank

6-2: second stage blank

6-3: third grade blank

6-4: dissimilar material binding zone

Detailed Description

The detailed features and advantages of the present invention are described in detail in the detailed description which follows, and will be sufficient for anyone skilled in the art to understand the technical content of the present invention and to implement the present invention, and the related objects and advantages of the present invention will be easily understood by those skilled in the art from the description, claims and drawings disclosed in the present specification.

Specific examples of components and arrangements are described below to simplify the present disclosure, but these are merely examples and do not limit the scope of the invention. For example, if a first feature is formed over or on a second feature described later in the specification, this may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features are formed between the first and second features, such that the first and second features may not be in direct contact. Additionally, reference numerals and/or letters may be repeated among the various examples throughout this disclosure. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, when a first element is described as being coupled or coupled to a second element, the description includes embodiments in which the first and second elements are directly coupled or coupled to each other, as well as embodiments in which one or more additional intervening elements are added to indirectly couple or couple the first and second elements to each other.

Further, it is to be understood that the positional or orientational relationships indicated by the terms "front, rear, upper, lower, left, right", "transverse, vertical, horizontal" and "top, bottom" and the like are generally based on the positional or orientational relationships illustrated in the drawings and are provided for convenience in describing the invention and for simplicity in description, and that these terms are not intended to indicate and imply that the referenced devices or elements must be in a particular orientation or be constructed and operated in a particular orientation without departing from the scope of the invention. Also, this application uses specific language to describe embodiments of the application. The terms "inside" and "outside" refer to the inner and outer parts relative to the outline of each part itself, and the terms "first" and "second" are used to define the parts, and are used only for the convenience of distinguishing the corresponding parts, and the terms do not have any special meaning unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means a feature, structure, or characteristic described in connection with at least one embodiment of the application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, certain features, structures, or characteristics may be combined as suitable in one or more embodiments of the application.

The invention provides a method for preparing a GH4169 and TA19 same-material and different-material multi-stage rotor assembly, which comprises a first disk body area made of GH4169 alloy and a second disk body area made of TA19 alloy, wherein the first disk body area is provided with at least one stage of rotor part, and the second disk body area is provided with at least one stage of rotor part. Preferably, at least one rotor portion of the first disk area and the second disk area is continuously arranged, and the first disk area can be arranged at the front stage of the second disk area and can also be arranged at the rear stage of the second disk area.

Firstly, dividing the multi-stage rotor assembly into a plurality of single-stage rotor parts according to the structural design and material selection requirements, and designing a hot isostatic pressing preform of each stage of single-stage rotor part of the rotor assembly according to the process characteristics of the hot isostatic pressing process near-net-shape forming and the processing requirements of a subsequent combined blank, wherein the hot isostatic pressing preform comprises a preparation scheme and the reserved amount of the single-stage preforms.

Preparing a sheath of each stage of preform according to the structure of each preform, wherein the sheath structure is basically the same as that of the final rotor assembly, a sheath interface is arranged at the position, connected with the adjacent sheath, of each stage of sheath, and the sheath interface is reserved in the prepared sheath.

The welding of the jackets and the filling of the alloy powder can adopt a sequence from back to front, the welding of the jackets and the preceding-stage jackets at the jacket interface is started from the last-stage jacket, the alloy powder is filled in the later-stage jacket of the two-stage jackets to be welded before the welding of each-stage jacket and is compacted by cold pressing, and the alloy powder compacted by the cold pressing method is integrated, so that the powder scattering or the powder mixing with the next stage cannot occur. And filling alloy powder into the first-stage sheath before welding the first-stage sheath, and performing cold pressing compaction, preferably, filling two-stage preforms at two ends in the rotor assembly when filling the powder, namely filling the alloy powder into the last-stage sheath, performing cold pressing compaction, and simultaneously filling the alloy powder into the first-stage sheath, and performing cold pressing compaction. And after welding with the sheath of the adjacent stage, filling the sheath of the adjacent stage with corresponding alloy powder, after cold pressing and compacting again, welding the sheath of the next adjacent stage at the interface position, filling the corresponding alloy powder again, and so on, and finally connecting the sheath with the preform at the other end of the rotor assembly by welding to complete powder filling and cold press molding of the whole preform, thereby obtaining the rotor assembly preform with each stage connected in sequence.

And carrying out hot isostatic pressing treatment on the rotor assembly preform subjected to cold pressing forming at the temperature of 1020-1070 ℃, under the pressure of 130-170 MPa and for 1.5-3 hours, so as to ensure the plastic deformation and diffusion creep of the powder, and finally forming a rotor assembly blank.

And (4) removing the sheath from the rotor assembly blank to finish the preparation of the GH4169 and TA19 alloy same-material and dissimilar-material multi-stage rotor assembly blank.

In response to the differing heat treatment regimes of the two alloys GH4169 and TA19, it was necessary to zoned heat treat the two alloy regions of the multi-stage rotor assembly to achieve the desired texture, i.e., heat treat the first and second disk regions of the rotor assembly blank separately, and heat treat the dissimilar material joining regions of the first and second disk regions together with the first disk region of the GH4169 alloy.

Further, the heat treatment includes solution treatment, and in order to reduce the influence of heat radiation due to excessive temperature difference, the solution treatment time and the aging treatment time of the two materials may be kept to be the same or close to each other, and therefore, the solution treatment performed on the first tray body region and the dissimilar material joining region using the GH4169 alloy may preferably be solution treatment by air cooling after heating to a temperature in the range of 950 ℃ to 980 ℃ for 1 hour to 3 hours, the aging treatment may preferably be aging treatment by air cooling after heating to a temperature in the range of 705 ℃ to 705 ℃ for 7 hours to 9 hours, followed by heat preservation at a temperature in the range of 605 ℃ to 635 ℃ for 7 hours to 9 hours, the solution treatment performed on the second tray body region using the TA19 alloy may preferably be solution treatment by air cooling after heating to a temperature in the range of 960 ℃ to 990 ℃ for 0.5 hours to 2.5 hours, and the aging treatment may preferably be solution treatment by air cooling after heating to a temperature in the range of 585 ℃ to 620 ℃ for 7 hours to 10 hours And carrying out air cooling aging treatment.

Preferably, the rotor assembly blank is inspected for internal quality by inspection, and preferably, the inspection is performed by water immersion inspection.

Preferably, the rotor assembly blank is finally subjected to a combined machining and stress relief treatment.

As shown in fig. 1, taking a three-stage rotor assembly 1 as an example, the three-stage rotor assembly comprises a first disk body region 1a and a second disk body region 1b, the first disk body region 1a comprises a second-stage rotor portion 1-2 and a third-stage rotor portion 1-3 which are selected from GH4169 alloy, the second disk body region 1b comprises a first-stage rotor portion 1-1 which is selected from TA19 alloy, and the three-stage rotor assembly 1 is prepared by hot isostatic pressing near-net shape forming, and comprises the following steps:

the method comprises the following steps: as shown in fig. 2, the rotor assembly is divided into three sections, i.e., three stages of single-stage rotor sections 1-1, 1-2, 1-3, and the preforms of the respective single-stage rotor sections, i.e., the first stage preform 2-1, the second stage preform 2-2, and the third stage preform 2-3, are designed in consideration of the reserved amount 5 of the preforms 2-1, 2-2, 2-3;

step two: as shown in fig. 3, jackets 3-1, 3-2 and 3-3 of each stage of prefabricated bodies 2-1, 2-2 and 2-3 of the three-stage rotor are designed and manufactured, and jacket interfaces 3-4 are reserved at the interface positions of adjacent jackets;

step three: as shown in fig. 4, firstly, filling GH4169 alloy powder 4-1 into the third-stage jacket 3-3, simultaneously filling TA19 alloy powder 4-2 into the first-stage jacket 3-1, compacting by a cold pressing method, welding the third-stage jacket 3-3 and the second-stage jacket 3-2 at the jacket interface 3-4, filling TA19 alloy powder 4-2 into the second-stage jacket 3-2 after welding, welding the second-stage jacket 3-2 and the first-stage jacket 3-1 at the jacket interface 3-4 after compacting by cold pressing again, and obtaining a three-stage rotor assembly preform;

step four: carrying out hot isostatic pressing treatment on the combined three-stage rotor assembly preform, wherein the hot isostatic pressing technological parameters are as follows: obtaining a three-stage rotor assembly blank 6 at the temperature of 1040-1060 ℃, the pressure of 140-150 MPa and the time of 1.5-2 hours, as shown in FIG. 5;

step five: performing combined machining or chemical treatment on the three-stage rotor assembly blank 6 to remove the sheath;

step six: heat treating the first stage blank 6-1 while simultaneously heat treating the second stage blank 6-2, the third stage blank 6-3 and the dissimilar material joining zone 6-4, comprising: firstly, heating a first-stage blank 6-1 to a temperature range of 960 ℃ to 990 ℃ and then carrying out air cooling after preserving heat for 1 hour, and simultaneously heating a second-stage blank 6-2, a third-stage blank 6-3 and a dissimilar material combining area 6-4 to a temperature range of 960 ℃ to 970 ℃ and then carrying out air cooling after preserving heat for 1 hour to 2 hours to complete solution treatment; then heating the first-stage blank 6-1 to 600 ℃, preserving heat for 9 hours, then carrying out air cooling, simultaneously heating the second-stage blank 6-2, the third-stage blank 6-3 and the dissimilar material combination area 6-4 to 720-730 ℃, preserving heat for 7-9 hours, then preserving heat for 7-9 hours at 620-630 ℃, and then carrying out air cooling to finish the aging treatment;

step eight: carrying out water immersion flaw detection on the third-stage rotor assembly blank 6;

step nine: and (4) carrying out combined machining on the three-stage rotor assembly blank 6, and carrying out stress relief treatment in the machining process.

According to a second aspect of the present invention, there is provided a GH4169 and TA19 homogeneous, heterogeneous material multi-stage rotor assembly 1 prepared using the preparation method as described above.

The GH4169 and TA19 homogeneous and heterogeneous material multistage rotor assembly can be advantageously applied to engines with high-performance and light-weight requirements such as aircraft engines.

The terms and expressions which have been employed herein are used as terms of description and not of limitation. The use of such terms and expressions is not intended to exclude any equivalents of the features shown and described (or portions thereof), and it is recognized that various modifications may be made within the scope of the claims. Other modifications, variations, and alternatives, such as the replacement of components of different specifications, may also exist. Accordingly, the claims should be looked to in order to cover all such equivalents.

Also, it should be noted that, although the present invention has been described with reference to the present specific embodiments, it should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and that various equivalent changes or substitutions may be made without departing from the spirit of the present invention, and therefore, changes and modifications to the above embodiments within the spirit of the present invention are to be made within the scope of the appended claims.

Claims

1. A method of making a GH4169 and TA19 homogeneous, heterogeneous material multi-stage rotor assembly having a first disk body region of a GH4169 alloy having at least one rotor section and a second disk body region of a TA19 alloy having at least one rotor section, the method comprising the steps of:

designing a preform for each rotor section of the rotor assembly;

performing hot isostatic pressing treatment on the rotor assembly preform at the temperature of 1020-1070 ℃, the pressure of 130-170 MPa and the time of 1.5-3 hours to obtain a rotor assembly blank;

removing the sheath from the rotor assembly blank;

2. A method of making a rotor assembly as claimed in claim 1,

the rotor part of the first disk body is continuously arranged, and the rotor part of the second disk body is continuously arranged.

3. A method of manufacturing as claimed in claim 2,

the first disk area is located at a preceding stage of the second disk area.

4. A method of manufacturing as claimed in claim 2,

the second disk body area is located at a preceding stage of the first disk body area.

5. A method of making as set forth in claim 1 wherein said first disk section includes a two-stage rotor portion and said second disk section includes a one-stage rotor portion.

6. A method according to claim 1, wherein the reaction mixture is heated,

and filling alloy powder into the sheath at the last stage and performing cold pressing, and simultaneously filling alloy powder into the sheath at the first stage and performing cold pressing and compacting.

7. A method according to claim 1, wherein the reaction mixture is heated,

the heat treatment comprises solution treatment, the first disc body area and the combination area are subjected to air cooling after heat preservation for 1 hour to 3 hours at the temperature of 950 ℃ to 980 ℃ and the second disc body area is subjected to air cooling after heat preservation for 0.5 hour to 2.5 hours at the temperature of 960 ℃ to 990 ℃.

8. A method according to claim 7, wherein the step of preparing the composition,

the heat treatment also comprises aging treatment, the aging treatment is carried out after the solid solution treatment, the first disk body area and the aging treatment carried out in the combination area are subjected to air cooling after the temperature is 705 ℃ to 735 ℃ within range for 7 hours to 9 hours, and the temperature is 605 ℃ to 635 ℃ within range for 7 hours to 9 hours, and the aging treatment carried out in the second disk body area is simultaneously carried out after the temperature is 585 ℃ to 620 ℃ within range for 7 hours to 10 hours.

9. The method of claim 1, further comprising, after the heat treating step:

carrying out flaw detection on the rotor assembly blank; and

10. A GH4169 and TA19 homogeneous, heterogeneous material multi-stage rotor assembly having a first disc region of GH4169 alloy with at least one stage rotor portion and a second disc region of TA19 alloy with at least one stage rotor portion, prepared using the method of preparation of claims 1-9.