Method for improving high-temperature tensile property of Ni3Al-based single crystal alloy and application

Abstract

The invention relates to the technical field of high-temperature alloy treatment, in particular to a method for improving the high-temperature tensile property of a Ni3Al-based single crystal alloy and application. The Ni3Al-based single crystal alloy with the [001] orientation is cut, and the Ni3Al-based single crystal alloy deviating along the [001] crystal orientation is obtained; the deviation angle ranges from 5 degrees to 20 degrees. By intentionally deviating from ideal crystal orientation and introducing a new slippage system and a deformation mechanism, the internal stress can be more effectively dispersed under a certain condition, the deformation coordination is improved, and the high-temperature tensile strength of the material is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of high temperature alloy processing, and in particular to a method for improving the high temperature tensile properties of a Ni3Al-based single crystal alloy and its application. Background Art

[0002] The single crystal preparation technology of Ni3Al-based single crystal alloy not only eliminates the defects of large impurities and irregular atomic arrangement at the grain boundaries, but also eliminates the transverse and longitudinal grain boundaries that are prone to crack initiation, making the alloy have excellent high-temperature properties. It is currently the main structural material for manufacturing advanced aircraft engines and gas turbine blades.

[0003] At present, Ni3Al-based single crystal alloys used in aircraft engines and gas turbine blades widely adopt

[001] orientation. Ni3Al-based single crystal alloys with this orientation have excellent high-temperature creep performance and convenient processing technology, but their high-temperature tensile performance needs to be improved. In applications, the tensile performance of Ni3Al-based single crystal alloys is an important performance indicator that directly affects their service life and reliability. Summary of the invention

[0004] The purpose of the present invention is to provide a method and application for improving the high temperature tensile properties of Ni3Al-based single crystal alloys, which can significantly improve the high temperature tensile strength of the material.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for improving the high temperature tensile properties of a Ni3Al-based single crystal alloy, comprising the following steps: cutting a

[001] -oriented Ni3Al-based single crystal alloy to obtain a Ni3Al-based single crystal alloy deviated along the

[001] crystal orientation; the deviation angle is 5 to 20 degrees.

[0007] Preferably, the deviation angle is 20°.

[0008] Preferably, after obtaining the Ni3Al-based single crystal alloy with a crystal orientation deviation along

[001] , the method further comprises subjecting the Ni3Al-based single crystal alloy with a crystal orientation deviation along

[001] to a standard heat treatment.

[0009] Preferably, the element composition of the

[001] oriented Ni3Al-based single crystal alloy is, in terms of mass percentage, Al4-8%, Re 1.2-3.0%, Mo 5-10%, Ta 1-3%, Cr 1-3%, B 0.003-0.005% and the balance Ni.

[0010] Preferably, the standard heat treatment is: keep warm at 1300°C for 2h, heat to 1305°C for 2h, heat to 1310°C for 2h, heat to 1315°C for 2h, heat to 1320°C for 2h, heat to 1325°C for 2h, heat to 1330°C for 4h, heat to 1335°C for 6h, heat to 1340°C for 2h, air cool to 1040°C for 2h, air cool to 870°C for 32h.

[0011] Preferably, the preparation of the

[001] -oriented Ni3Al-based single crystal alloy comprises the following steps:

[0012] Mixing raw materials for preparing Ni3Al-based single crystal alloy, and smelting to obtain a master alloy ingot;

[0013] The

[001] -oriented seed crystal is used as a seed crystal, and the master alloy ingot is melted and then directionally solidified to obtain the

[001] -oriented Ni3Al-based single crystal alloy.

[0014] Preferably, before the cutting, the method further includes performing surface mechanical grinding on the

[001] oriented Ni3Al-based single crystal alloy.

[0015] The present invention provides an application of a Ni3Al-based single crystal alloy in a high-temperature working scenario, wherein the Ni3Al-based single crystal alloy is a

[001] -oriented Ni3Al-based single crystal alloy obtained by processing the method described in any one of claims 1 to 7.

[0016] Preferably, the temperature of the high temperature working scene is 900-1100°C.

[0017] Preferably, the high temperature working scenario includes being used as a component material for aircraft engine and / or gas turbine blades.

[0018] The present invention provides a method for improving the high temperature tensile properties of a Ni3Al-based single crystal alloy, comprising the following steps: cutting a

[001] -oriented Ni3Al-based single crystal alloy to obtain a Ni3Al-based single crystal alloy deviated along the

[001] crystal orientation; the angle of the deviation is 5 to 20 degrees. The present invention introduces a new slip system and deformation mechanism by intentionally deviating from the ideal crystal orientation, which can more effectively disperse the internal stress under certain conditions, improve the coordination of deformation, and thus improve the high temperature tensile strength of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a statistical diagram of the activatable slip systems of Ni3Al-based single crystal alloys with different deviations along the

[001] crystal orientation. DETAILED DESCRIPTION

[0020] The present invention provides a method for improving the high temperature tensile properties of a Ni3Al-based single crystal alloy, comprising the following steps: cutting a

[001] -oriented Ni3Al-based single crystal alloy to obtain a Ni3Al-based single crystal alloy deviated along the

[001] crystal orientation; the deviation angle is 5 to 20 degrees.

[0021] In the present invention, the element composition of the

[001] oriented Ni3Al-based single crystal alloy is preferably, in terms of mass percentage, Al 4-8%, Re 1.2-3.0%, Mo 5-10%, Ta 1-3%, Cr 1-3%, B 0.003-0.005% and the balance Ni.

[0022] In the present invention, the preparation of the

[001] oriented Ni3Al-based single crystal alloy preferably comprises the following steps:

[0023] Mixing raw materials for preparing Ni3Al-based single crystal alloy, and smelting to obtain a master alloy ingot;

[0024] The

[001] -oriented seed crystal is used as a seed crystal, and the master alloy ingot is melted and then directionally solidified to obtain the

[001] -oriented Ni3Al-based single crystal alloy.

[0025] The present invention has no special requirements for the melting and directional solidification process, and the melting and directional solidification process well known in the art can be used.

[0026] In the present invention, before the cutting, it is preferred that the surface of the

[001] oriented Ni3Al-based single crystal alloy is mechanically ground.

[0027] The present invention has no special requirements for the cutting method, as long as the deviation from the

[001] crystal orientation is 5 to 20° during cutting; in a specific embodiment of the present invention, the deviation angle can be 5°, 8°, 10°, 13°, 15°, 17° or 20°. In the present invention, when the deviation angle is 20°, the high temperature tensile properties of the Ni3Al-based single crystal alloy are most significantly improved. In the present invention, any direction along the

[001] crystal orientation can deviate from the above angle.

[0028]

[001] Different orientation deviations correspond to different orientation factors and different numbers of activated slip systems. The present invention controls the crystal orientation deviation of the single crystal alloy by cutting the

[001] oriented Ni3Al-based single crystal alloy, optimizes the activation mode of the slip system, and thereby improves the high-temperature tensile properties of the Ni3Al-based single crystal alloy.

[0029] In the present invention, after obtaining the Ni3Al-based single crystal alloy deviating from the

[001] crystal orientation, it is preferred to further include subjecting the Ni3Al-based single crystal alloy deviating from the

[001] crystal orientation to standard heat treatment.

[0030] The present invention has no special requirements for the standard heat treatment, and can be carried out according to the corresponding standard heat treatment system for different Ni3Al-based single crystal alloys. In the present invention, when the element composition of the Ni3Al-based single crystal alloy is Al 4-8%, Re 1.2-3.0%, Mo 5-10%, Ta 1-3%, Cr 1-3%, B 0.003-0.005% and the balance Ni, the standard heat treatment is preferably: keep warm at 1300°C for 2h, heat to 1305°C for 2h, heat to 1310°C for 2h, heat to 1315°C for 2h, heat to 1320°C for 2h, heat to 1325°C for 2h, heat to 1330°C for 4h, heat to 1335°C for 6h, heat to 1340°C for 2h, Air cool to 1040℃ and keep warm for 2h, air cool to 870℃ and keep warm for 32h; abbreviated as: 1300℃ / 2h+1305℃ / 2h+1310℃ / 2h+1315℃ / 2h+1320℃ / 2h+1325℃ / 2h+1330℃ / 4h+1335℃ / 6h+1340℃ / 2h, AC+1040℃ / 2h, AC+870℃ / 32h, AC; among which, AC stands for air cooling.

[0031] In the present invention, the standard heat treatment is preferably performed under a vacuum atmosphere.

[0032] The present invention can reduce dendrite segregation by performing standard heat treatment, and can also adjust the dissolution and precipitation of various phases, so that the strengthening phase γ' particles have the best quantity, size and distribution, and the alloy has good organization and performance.

[0033] The present invention provides an application of a Ni3Al-based single crystal alloy in a high-temperature working scenario. The nickel-based single crystal high-temperature alloy is a

[001] -oriented Ni3Al-based single crystal alloy obtained by processing the above-described method.

[0034] In the present invention, the temperature of the high temperature working scene is preferably 900-1100°C, and in a specific embodiment, it can be 900°C, 1000°C or 1100°C.

[0035] In the present invention, the high temperature working scenario preferably includes being a component material of aircraft engine and / or gas turbine blades.

[0036] After the

[001] -oriented Ni3Al-based single crystal alloy is treated by the method described above, the high-temperature tensile properties are significantly improved. As the main structural material for manufacturing advanced aircraft engines and gas turbine blades, the service life and reliability of engine and gas turbine blades can be improved.

[0037] The method and application of improving the high temperature tensile properties of Ni3Al-based single crystal alloy provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0038] Examples 1 to 3 and Comparative Examples 1 to 2

[0039] According to the element ratio of Ni3Al-based single crystal alloy, the element ratio is: Al4-8%, Re1.2-3.0%, Mo5-10%, Ta1-3%, Cr1-3%, B0.003-0.005% and the balance Ni, a master alloy ingot is prepared; then, a seed crystal with

[001] orientation is used as a seed, the master alloy ingot is melted, and then directionally solidified to obtain a Ni3Al-based single crystal alloy with

[001] orientation;

[0040] The surface of the

[001] -oriented Ni3Al-based single crystal alloy was mechanically ground and then cut. The cutting was deviated along

[001] . The deviation angles are shown in Table 1. The cut Ni3Al-based single crystal alloys with different

[001] -oriented deviation angles were subjected to a uniform standard heat treatment in a vacuum atmosphere.

[0041] The unified standard heat treatment is: 1300℃ / 2h+1305℃ / 2h+1310℃ / 2h+1315℃ / 2h+1320℃ / 2h+1325℃ / 2h+1330℃ / 4h+1335℃ / 6h+1340℃ / 2h, AC+1040℃ / 2h, AC+870℃ / 32h, AC.

[0042] The Ni3Al-based single crystal alloy with different deviation angles from the

[001] orientation after standard heat treatment was subjected to high temperature tensile property test at 980°C. The test results are shown in Table 1.

[0043] The high temperature tensile performance test adopts the HB5195-96 metal high temperature tensile test method.

[0044] Table 1 Deviation angle and tensile properties test results of examples and comparative examples

[0045] serial number Deviation Angle Tensile strength / MPa Comparative Example 1 0°

[001] orientation 760 Example 1 5° 770 Example 2 10° 830 Example 3 20° 852 Comparative Example 2 45°

[011] orientation 735

[0046] It can be seen from the results in Table 1 that, compared with the Ni3Al-based single crystal alloy oriented in the

[001] direction in the comparative example 1, the present invention can effectively improve the high-temperature tensile properties of the Ni3Al-based single crystal alloy by deviating from the

[001] direction by 5 to 20°. In particular, when the deviation from the

[001] direction is 20°, the tensile strength is as high as 852MPa. When the deviation angle is greater than 20°, such as when the deviation angle reaches 45° in the comparative example 2, the high-temperature tensile strength of the Ni3Al-based single crystal alloy oriented in the

[001] direction does not increase but decreases.

[0047] The orientation factors (also known as Schmid factors, the calculation process is well known in the art) of the Ni3Al-based single crystal alloys with different deviation angles from the

[001] orientation after standard heat treatment of the embodiments and comparative examples are calculated. The results are shown in Tables 2 and Figure 1 ( Figure 1 , 001-5° represents a deviation of 5° from the

[001] orientation, and so on).

[0048] Table 2 Calculation of orientation factors of examples and comparative examples

[0049]

[0050] From Table 2 and Figure 1 The results show that the number of activatable slip systems of the

[001] -oriented Ni3Al-based single crystal alloy in comparative example 1 is 8, while the number of activatable slip systems of the Ni3Al-based single crystal alloys in embodiments 1 to 3 that deviate from the

[001] orientation by 5 to 20° is increased, with the number of activatable slip systems in embodiment 3 being as high as 16. The existence of multiple slip systems helps to improve the deformation coordination of the material at high temperatures and prevent stress concentration caused by the activation of a single slip system, thereby improving the tensile strength at 980°C.

[0051] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for improving the high temperature tensile properties of Ni3Al-based single crystal alloy, characterized in that: The following steps are involved: The Ni3Al-based single crystal alloy with [001] orientation is cut to obtain the Ni3Al-based single crystal alloy deviated along the [001] crystal orientation; the angle of the deviation is 5 to 20 degrees.

2. The method according to claim 1, characterized in that The angle of deviation is 20°.

3. The method according to claim 1, characterized in that: After obtaining the Ni3Al-based single crystal alloy with a [001] crystal orientation deviation, the method further includes subjecting the Ni3Al-based single crystal alloy with a [001] crystal orientation deviation to a standard heat treatment.

4. The method according to claim 3, characterized in that: Calculated by mass percentage, the element composition of the [001] oriented Ni3Al-based single crystal alloy is: Al 4-8%, Re 1.2-3.0%, Mo 5-10%, Ta 1-3%, Cr 1-3%, B 0.003-0.005% and the balance Ni.

5. The method according to claim 4, characterized in that The standard heat treatment is: keep warm at 1300°C for 2h, heat to 1305°C for 2h, heat to 1310°C for 2h, heat to 1315°C for 2h, heat to 1320°C for 2h, heat to 1325°C for 2h, heat to 1330°C for 4h, heat to 1335°C for 6h, heat to 1340°C for 2h, air cool to 1040°C for 2h, air cool to 870°C for 32h.

6. The method according to claim 1 or 4, characterized in that: The preparation of the [001]-oriented Ni3Al-based single crystal alloy comprises the following steps: Mixing raw materials for preparing Ni3Al-based single crystal alloy, and smelting to obtain a master alloy ingot; The [001]-oriented seed crystal is used as a seed crystal, and the master alloy ingot is melted and then directionally solidified to obtain the [001]-oriented Ni3Al-based single crystal alloy.

7. The method according to claim 1, characterized in that Before the cutting, the surface of the [001] oriented Ni3Al-based single crystal alloy is mechanically ground.

8. Application of Ni3Al-based single crystal alloy in high temperature working scenarios, characterized in that: The Ni3Al-based single crystal alloy is a [001]-oriented Ni3Al-based single crystal alloy obtained by processing the method described in any one of claims 1 to 7.

9. The use according to claim 8, characterized in that: The temperature of the high temperature working scene is 900-1100°C.

10. The use according to claim 8 or 9, characterized in that: The high temperature working scenario includes being used as a component material of aircraft engine and / or gas turbine blades.

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