CN109234655B

CN109234655B - Method for improving relaxation stability of GH4169 high-temperature alloy

Info

Publication number: CN109234655B
Application number: CN201811131261.1A
Authority: CN
Inventors: 江河; 杨静; 董建新
Original assignee: University of Science and Technology Beijing USTB
Current assignee: University of Science and Technology Beijing USTB
Priority date: 2018-09-27
Filing date: 2018-09-27
Publication date: 2020-09-11
Anticipated expiration: 2038-09-27
Also published as: CN109234655A

Abstract

The invention relates to the technical field of high-temperature alloys, and provides a method for improving the relaxation stability of GH4169 high-temperature alloy, which is characterized in that the alloy with high phase content is obtained by carrying out heat treatment on the GH4169 high-temperature alloy, so that the relaxation stability of the GH4169 high-temperature alloy is improved; the specific process can be as follows: heating GH4169 high-temperature alloy to 890-910 ℃, preserving heat for 8-15h, and performing water quenching treatment; then heating to 700-750 ℃ and preserving heat for 5-10h, and air cooling; heating to 600-650 ℃, preserving heat for 5-10h, and air cooling to room temperature to obtain the GH4169 alloy with high phase content. The invention has the beneficial effects that: fills the technical blank of how to improve the relaxation stability of the alloy at home and abroad; the method is simple and easy to implement and has wide application prospect.

Description

Method for improving relaxation stability of GH4169 high-temperature alloy

Technical Field

The invention relates to the technical field of high-temperature alloys, in particular to a method for improving relaxation stability of GH4169 high-temperature alloy.

Background

Regardless of the type of force transmission, a feature of the static connection is that the connecting members secure the connected members together, so loosening and loosening of the connection is a major failure mode. Thus, for fastener materials, the relaxation behavior is more reflective of the material properties than the holding strength.

The research report of the relaxation stability of the high-temperature alloy at home and abroad mainly focuses on the mechanical property, and the literature at home and abroad lacks corresponding research report about the improvement of the relaxation stability through tissue adjustment.

The GH4169 alloy is a typical nickel-based superalloy that is used for superalloy fasteners because of its superior properties. In the process of long-term service in a high-temperature environment, the fastener can loosen and even loosen to cause the failure of the fastener, and the normal operation of an engine and the like is seriously influenced. The relaxation stability is one of the important indicators for evaluating the performance of fasteners.

How to improve the stress relaxation resistance of the alloy is lack of corresponding research reports in domestic and foreign documents.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for improving the relaxation stability of a high-temperature alloy according to the correlation between the state of a metal structure and the relaxation performance.

The technical scheme of the invention is as follows:

the method for improving the relaxation stability of the GH4169 high-temperature alloy is characterized in that the GH4169 high-temperature alloy in a standard state is subjected to heat treatment to obtain an alloy with a high phase content, so that the relaxation stability of the GH4169 high-temperature alloy is improved.

Further, the specific process of the heat treatment is as follows: heating GH4169 high-temperature alloy to 890-910 ℃, preserving heat for 8-15h, and performing water quenching treatment; then heating to 700-750 ℃ and preserving heat for 5-10h, and air cooling; then heating to 600-650 deg.C and keeping the temp. for 5-10h, air-cooling to room temp.

Further, the specific process of the heat treatment is as follows: heating GH4169 high-temperature alloy to 900 ℃, preserving heat for 10 hours, and performing water quenching treatment; heating to 720 ℃ and preserving heat for 8h, and cooling in air; then heated to 620 ℃ and kept warm for 8h, and cooled to room temperature by air.

The invention also provides a GH4169 high-temperature alloy with high relaxation stability, and the GH4169 high-temperature alloy is treated by the method.

The invention also provides a high-relaxation-stability connecting piece or fastener, which is made of the GH4169 high-temperature alloy with high relaxation stability.

The invention has the beneficial effects that: fills the technical blank of how to improve the relaxation stability of the alloy at home and abroad; the method is simple and easy to implement and has wide application prospect.

Drawings

FIG. 1 is a transmission electron micrograph showing the interaction among dislocations, phases and grain boundaries in an GH4169 alloy according to an embodiment of the present invention;

FIG. 2 is a structural morphology diagram of a high-phase content GH4169 alloy;

wherein (a) the grain structure; (b) phase, gamma 'phase and gamma' phase morphology.

FIG. 3 shows stress relaxation curves of GH4169 alloys with different phase contents.

Detailed Description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that technical features or combinations of technical features described in the following embodiments should not be considered as being isolated, and they may be combined with each other to achieve better technical effects. In the drawings of the embodiments described below, the same reference numerals appearing in the respective drawings denote the same features or components, and may be applied to different embodiments.

Embodiments of the present invention aim to improve the relaxation stability of GH4169 alloys.

Example 1

Standard GH4169 alloy was heat treated as follows: heating GH4169 high-temperature alloy to 900 ℃, preserving heat for 10 hours, and performing water quenching treatment; heating to 720 ℃ and preserving heat for 8h, and cooling in air; heating to 620 ℃ and preserving heat for 8h, and air-cooling to room temperature to obtain the GH4169 alloy with high phase content.

The following illustrates the principles of the present application:

the GH4169 alloy with high phase content can be obtained by changing the heat treatment process: the relaxation stability of the GH4169 alloy with high phase content is better than that of the GH4169 alloy in a standard state because relative dislocation movement and grain boundary migration have blocking effects.

FIG. 1 shows a transmission electron micrograph of the interaction among dislocations, phases and grain boundaries in a GH4169 alloy. The phase not only can block dislocation movement to a certain extent, but also has a pinning effect on grain boundary migration. As the phase content increases, the dominant mechanism of stress relaxation shifts from grain boundary migration to dislocation motion. This is because many phases are distributed in the form of short rods at the grain boundaries, and the grain boundaries can be effectively pinned, thereby inhibiting the movement of the grain boundaries. It also demonstrates the feasibility of the hypothesis of improving the relaxation stability of GH4169 alloys by increasing the phase content.

The morphology of the high-phase-content GH4169 alloy structure after heat treatment is shown in FIG. 2, wherein (a) the grain structure; (b) phase, gamma 'phase and gamma' phase morphology.

FIG. 3 is a stress relaxation curve comparison of standard state GH4169 alloy and high phase content GH4169 alloy. The standard GH4169 alloy has obvious stress reduction in a long time and becomes stable gradually after 4000 min. Whereas the high phase content GH4169 alloy only relaxed stress for a short time, reaching a steady state already at 500 min. In addition, it can be intuitively observed from the stress relaxation curve that the total relaxation stress of the high phase content GH4169 alloy is significantly less than that of the standard state GH4169 alloy.

Further, relaxation stability determination parameters such as relaxation limit, total relaxation stress and relaxation stability coefficient of the high phase content GH4169 alloy under different initial stress conditions were calculated and obtained, as shown in Table 1. In order to conveniently compare various parameters corresponding to the GH4169 alloy in the standard state, the comparison shows that: when the initial stress is 260MPa, the relaxation limit of the high-phase-content GH4169 alloy is increased by 70.4%, the total relaxation stress is reduced by 57.9%, and the relaxation stability coefficient is increased by more than two times, which shows that the relaxation stability can be improved by increasing the phase content.

TABLE 1 relaxation stability parameters of GH4169 alloys with different phase contents

Example 2

Standard GH4169 alloy was heat treated as follows: heating GH4169 high-temperature alloy to 910 ℃, preserving heat for 9 hours, and performing water quenching treatment; heating to 700 deg.C, keeping the temperature for 10h, and air cooling; heating to 620 ℃ and preserving heat for 8h, and air-cooling to room temperature to obtain the GH4169 alloy with high phase content.

Example 3

Standard GH4169 alloy was heat treated as follows: heating GH4169 high-temperature alloy to 890 ℃, preserving heat for 15h, and performing water quenching treatment; heating to 750 deg.C, keeping the temperature for 5h, and air cooling; heating to 600 deg.C, keeping the temperature for 7h, and air cooling to room temperature to obtain GH4169 alloy with high phase content.

Example 4

Standard GH4169 alloy was heat treated as follows: heating GH4169 high-temperature alloy to 900 ℃, preserving heat for 12 hours, and performing water quenching treatment; heating to 750 deg.C, keeping the temperature for 7h, and air cooling; heating to 650 ℃, preserving the temperature for 5 hours, and cooling in air to room temperature to obtain the GH4169 alloy with high phase content.

The GH4169 high-temperature alloy with high relaxation stability treated by the method can be used for manufacturing connecting pieces or fasteners, has high relaxation stability, and can be widely applied to engineering practice.

While several embodiments of the present invention have been presented herein, it will be appreciated by those skilled in the art that changes may be made to the embodiments herein without departing from the spirit of the invention. The above examples are merely illustrative and should not be taken as limiting the scope of the invention.

Claims

1. A method for improving the relaxation stability of GH4169 high-temperature alloy is characterized in that the method obtains the alloy with high phase content by carrying out heat treatment on the GH4169 high-temperature alloy, thereby improving the relaxation stability of the GH4169 high-temperature alloy;

the specific process of the heat treatment comprises the following steps: heating GH4169 high-temperature alloy to 890-910 ℃, preserving heat for 8-15h, and performing water quenching treatment; then heating to 700-750 ℃ and preserving heat for 5-10h, and air cooling; then heating to 600-650 deg.C and keeping the temp. for 5-10h, air-cooling to room temp.

2. The method for improving the relaxation stability of the GH4169 superalloy as claimed in claim 1, wherein the specific process of the heat treatment is as follows: heating GH4169 high-temperature alloy to 900 ℃, preserving heat for 10 hours, and performing water quenching treatment; heating to 720 ℃ and preserving heat for 8h, and cooling in air; then heated to 620 ℃ and kept warm for 8h, and cooled to room temperature by air.

3. A GH4169 superalloy with high relaxation stability, wherein the GH4169 superalloy has been treated according to any of claims 1-2.

4. A high relaxation stability connector or fastener, wherein the connector or fastener is made of the high relaxation stability GH4169 superalloy as claimed in claim 3.