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Solution treatment method for precise control of structure and properties of gh720li alloy

A solution treatment and precise control technology, applied in the direction of design optimization/simulation, etc., can solve the problems of lack of in-depth reports, difficulty in precise control of alloy microstructure and properties, and the variation law of γ' phase redissolution with holding time, etc. The effect of reducing manpower, optimizing alloy solution treatment process conditions, and improving production efficiency

Active Publication Date: 2020-10-20
AVIC BEIJING INST OF AERONAUTICAL MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Overseas studies have been carried out on the changes of primary γ′ phase residual content and grain size in alloys held at 1085-1145°C for different times [Jackson M P, Reed R C.Heattreatment of Udimet 720Li: the effect of microstructure on properties[J]. Materials Science and Engineering A,1999,259:85-97], however, there is no research on the more sensitive temperature range of 1145~1170℃, and there is a lack of in-depth reports
At present, there is still a lack of systematic reports on the γ′ phase and grain structure of the alloy during the solution treatment process.
[0004] In addition, during the solid solution treatment of GH720Li alloy, a large number of experiments are needed to characterize the dynamic change law of the characteristic value of the γ′ phase resolubility, and the γ′ phase resolubility speed is very fast under some high temperature conditions, and the experimental or technological means cannot be well understood. Given the change law of the γ′ phase back-dissolution with the holding time, it is difficult to achieve precise control of the microstructure and properties of the alloy through the solid solution process.

Method used

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  • Solution treatment method for precise control of structure and properties of gh720li alloy

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Experimental program
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Embodiment 1

[0029] The steps of the solid solution treatment method that adopts the precise control of the microstructure and properties of the GH720Li alloy of the present invention are as follows:

[0030] Step 1. After the GH720Li alloy is homogenized and billet forged, it is kept at 1155°C for 5, 10, 20, 30, 60, 240 and 480 minutes, then water-cooled, and then the residual volume fraction of the γ′ phase is measured once to be 12.46 %, 8.16%, 6.36%, 5.03%, 4.16%, 1.19% and 0, the average grain size is 3.73, 4.53, 5.12, 7.68, 28.56, 49.57 and 68.14 μm;

[0031] Step 2. Observing the distribution of the primary γ′ phase and grains under the scanning electron microscope, when the holding time at 1155°C is less than 60 minutes, the residual volume fraction of the primary γ′ phase is greater than 4.5%, and the alloy is a uniform fine-grained structure above ASTM 8.0 ;When the holding time is 60-240min, when the residual volume fraction of the primary γ′ phase is in the range of 2.8%-4.5%, ...

Embodiment 2

[0036] The steps of the solid solution treatment method that adopts the precise control of the microstructure and properties of the GH720Li alloy of the present invention are as follows:

[0037]Step 1. After the GH720Li alloy is homogenized and billet forged, it is kept at 1170°C for 5, 10, 20 and 60 minutes, and then water-cooled, and then the residual volume fraction of the γ′ phase is measured once to be 9.87%, 4.62%, and 2.67%, respectively. % and 0, the average grain size is 4.71, 8.78, 26.39 and 156.53 μm, respectively;

[0038] Step 2. Observing the distribution of the primary γ′ phase and grains under the scanning electron microscope, when the holding time at 1170°C is less than 20 minutes, the residual volume fraction of the primary γ′ phase is greater than 4.5%, and the alloy is a uniform fine-grained structure above ASTM 8.0 ; when the holding time is 20 to 60 minutes, when the residual volume fraction of the primary γ′ phase is in the range of 0.5% to 2.8%, it is ...

Embodiment 3

[0043] The steps of the solid solution treatment method that adopts the precise control of the microstructure and properties of the GH720Li alloy of the present invention are as follows:

[0044] Step 1. After the GH720Li alloy is homogenized and billet forged, it is kept at 1145°C for 60, 120, 240 and 480 minutes, then water-cooled, and then the residual volume fraction of the γ′ phase is measured once. They are 9.91%, 9.43%, 7.42 % and 5.09%, the average grain size is 5.42, 6.45, 9.08 and 12.18 μm, respectively;

[0045] Step 2. Observing the distribution of the primary γ′ phase and grains under the scanning electron microscope, when the holding time at 1145°C is less than 480 minutes, the residual volume fraction of the primary γ′ phase is greater than 4.5%, and the alloy is a uniform fine-grained structure above ASTM 8.0 ;

[0046] Step 3. Based on the revised JMAK transformation kinetics model, simulate and verify the variation of the residual volume fraction of the prim...

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Abstract

The invention discloses a solid-solution treatment method capable of achieving GH720Li alloy structure property accuracy control. According to the method, through the change rule between one-time gamma' phase and the grain structure under the different solid-solution conditions, the corresponding relation between the two can be obtained, a one-time gamma' phase redissolution transformation power model shown in the specification under the different solid-solution temperatures T and the heat preservation time t is used for obtaining solid-solution treatment process conditions corresponding to the different grain structure characteristics of the alloy, that is the solid solution temperature and heat preservation time optimization. The manpower and material resource consumption caused by the traditional solid-solution treatment process can be avoided, the duplex grain structure not beneficial to the performance can be intelligently avoided, and the structure performance precise control ofthe GH720Li alloy under the different application need conditions can be achieved.

Description

technical field [0001] The invention relates to a solid solution treatment method for precisely controlling the microstructure and performance of GH720Li alloy, and belongs to the field of heat treatment technology of nickel-based superalloys. Background technique [0002] GH720Li alloy has high high temperature strength, fatigue resistance and creep resistance, sulfur corrosion resistance and oxidation resistance. It can be widely used in aero-engine turbine disks, turbine blades and fasteners, and can also be used to make a new generation of strategic missiles and Integral turbine rotors for high-thrust rocket engines, and turbine disks for ground gas turbines, etc. According to different application requirements, the requirements for the microstructure and performance of the alloy parts are different, and the heat treatment systems implemented are also different. Since solution treatment has a significant effect on the grain structure of the alloy, and then significantly...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22F1/10G06F30/20
CPCC22F1/10
Inventor 于秋颖方爽兰博张敏聪林莺莺
Owner AVIC BEIJING INST OF AERONAUTICAL MATERIALS