CN104372277A - Granular delta-phase uniformly distributed GH4169 alloy preparation method - Google Patents

Abstract

The invention relates to a granular delta-phase uniformly distributed GH4169 alloy preparation method and belongs to the technical field of preparation of high-temperature alloy materials. On the basis of combination of cold deformation and heat treatment processes, the method includes GH4169 alloy cold deformation and heat treatment. Firstly, plate blanks are subjected to cold rolling deformation more than 30% after solid solution and quickly cooled under vacuum argon shielding after heat preservation at 985+/5 DEG C for 1h; secondly, the plate blanks are subjected to standard double aging treatment; finally, granular delta phases uniformly distributed in grains and at grain boundaries of GH4169 alloy are acquired. Therefore, GH4169 alloy strength is improved, and crack growth rate of the GH4169 alloy is decreased to acquire better fatigue performance.

Description

A preparation method of GH4169 alloy with uniform distribution of granular delta phase

technical field

The invention relates to a method for preparing a GH4169 alloy with evenly distributed granular delta phases, and belongs to the technical field of high-temperature alloy material preparation.

Background technique

Since the GH4169 alloy has high yield strength, tensile strength, durable strength and plasticity between -253 and 650 ° C, and has good corrosion resistance, radiation resistance, thermal processing and welding properties, it is widely used in aviation, aerospace, petroleum, etc. It has a wide range of uses in the fields of chemical, chemical and energy, and its consumption accounts for more than 45% of the world's total output of deformed superalloys. Therefore, the change of its microstructure and phase has always been the focus of research by scholars at home and abroad, especially the content, distribution and shape change of the δ phase in the alloy, which is a hot spot in the research.

Studies have shown that δ has an important influence on the strength and crack initiation and propagation of GH4169 alloy. In the study on the influence of δ relative to the mechanical properties of GH4169 alloy at room temperature, it was found that when the δ phase with a mass fraction of 3.45% was precipitated in the alloy, its yield and tensile strength increased by 233MPa and 181MPa, respectively, because the δ phase was on the grain boundary Precipitation reduces the notch sensitivity of the alloy; and Si Jiayong et al. [Si Jiayong, Liu Feng. Research progress on the influence of δ relative to the structure and fatigue properties of Inconel 718 alloy. Materials Herald. 2013(07):89-92 .] show that the mechanical properties of the alloy are the best when the δ phase is precipitated in granular form and uniformly distributed in the grain boundary and in the grain, because the hindering effect of the δ relative dislocation changes from bypassing to shearing mechanism during deformation , the strength of the alloy is further improved. In addition, Viskari et al [L Viskari, Y Cao, M Norell, et al. Grainboundary microstructure and fatigue crack growth in Allvac 718Plus superalloy.2011,528(6):2570-2580] analyzed the Inconel 718 alloy (GH4169) containing δ The change of the endurance fatigue limit of the alloy with and without the δ phase. The research results show that: when the δ phase exists in the alloy, the crack growth rate can be effectively reduced, thereby improving the endurance fatigue performance of the material. In the hot forming process, because the temperature is greatly affected by the surrounding environment, the temperature field distribution of the workpiece or blank is often very uneven, and the content, morphology and distribution of the δ phase are very sensitive to temperature. The use of hot forming method has low efficiency and high energy consumption, and the surface of the workpiece or blank will also be severely oxidized due to high temperature. Therefore, it is not feasible to obtain a uniform distribution of granular δ phase by thermoforming.

Therefore, it is necessary to consider separating the deformation of GH4169 alloy from the precipitation of δ phase during heat treatment, and finally obtain the granular δ phase uniformly distributed in the grain boundary and within the grain.

Contents of the invention

The purpose of the present invention is to provide a high-efficiency preparation method of GH4169 alloy with uniform distribution of granular δ phase based on the combination of cold deformation and heat treatment process, so as to further improve the strength of GH4169 alloy, reduce its crack growth rate and improve fatigue life.

Technical scheme of the present invention is:

A preparation method of GH4169 alloy with uniform distribution of granular δ phase, including cold deformation and heat treatment of GH4169 alloy. Firstly, the slab after solid solution is subjected to cold rolling deformation of more than 30%, and then it is kept at 985°C ± 5°C for 1 hour. Rapid cooling under the protection of vacuum argon, and then the standard double aging treatment on the slab, finally obtained the granular δ phase uniformly distributed in the grain boundaries and grains of the GH4169 alloy.

The preparation method of the GH4169 alloy in which the granular δ phase is uniformly distributed, the cold deformation and heat treatment of the GH4169 alloy include the following steps:

a) The GH4169 sheet is subjected to solid solution treatment at 985°C±5°C for 1h;

b) Carry out rolling deformation to the slab with a deformation amount of more than 30%;

c) cleaning the cold deformed slab with alcohol or acetone;

d) Carry out heat treatment on the cold deformed slab, the heat treatment system is: 985°C ± 5°C for 1h, rapid cooling under the protection of vacuum argon;

e) Perform double aging treatment on the slab: heat preservation at 720°C±5°C for 8 hours, cool at 50°C/h to 620°C±5°C and heat preservation for 8 hours, and rapidly cool under the protection of vacuum argon.

In the preparation method of the GH4169 alloy in which the granular δ phase is uniformly distributed, the deformation amount of the slab is preferably 40-70% after rolling deformation.

Design idea of the present invention is:

In the present invention, firstly, the GH4169 alloy slab after solid solution is subjected to more than 30% cold-rolling deformation; then it is rapidly cooled under the protection of vacuum argon after being kept at a specific temperature of 985°C ± 5°C for 1 hour; and then the slab is subjected to double aging treatment ( 720°C ± 5°C for 8 hours, cooled at 50°C/h to 620°C ± 5°C for 8 hours, and cooled under the protection of vacuum argon). In this way, the granular δ phase uniformly distributed in the alloy grain boundary and in the grain can be obtained, and finally the purpose of improving the strength of the GH4169 alloy, reducing its crack growth rate, and obtaining better fatigue performance can be achieved.

Advantage of the present invention and beneficial effect are:

The invention includes two parts of cold deformation and heat treatment of GH4169 alloy, and the granular δ phase uniformly distributed in the grain boundary and in the grain can be obtained by using the invention, which not only improves the strength of GH4169 alloy, reduces its crack growth rate, but also improves production efficiency, Reduce material oxidation and reduce material waste.

Description of drawings

Figure 1 is a scanning electron microscope image of GH4169 alloy.

Detailed ways

In a specific embodiment, the method for preparing a GH4169 alloy with a uniform distribution of granular δ phases of the present invention includes cold deformation and heat treatment of the GH4169 alloy, and the cold deformation and heat treatment include the following steps:

a) Firstly, the GH4169 sheet is subjected to solution treatment at 985°C±5°C for 1 hour to eliminate the residual stress, structure and phase inhomogeneity caused by the deformation history;

b) Carry out rolling deformation to the slab with a deformation amount of more than 30% (generally 40-70%), and pay attention to the cleaning of the slab and the lubricating effect of the roll during the deformation process;

c) Clean the slab after cold deformation with alcohol or acetone to remove the oil stain on the surface of the slab and prevent it from being severely oxidized during subsequent heat treatment;

d) Perform heat treatment on the cold deformed slab. The heat treatment system is: 985°C±5°C for 1h, and rapid cooling under the protection of vacuum argon (evacuate first, then fill with argon). Among them, the heat treatment temperature can be appropriately increased with the increase of deformation, and the maximum temperature should not exceed 990 °C;

e) Finally, double-aging treatment is performed on the slab: heat preservation at 720°C±5°C for 8 hours, cooling at 50°C/h to 620°C±5°C and heat preservation for 8 hours, rapid cooling under vacuum argon protection.

The present invention will be further described in detail below through the embodiments and the accompanying drawings.

Example

The GH4169 sheet is subjected to solution treatment at 985°C for 1 hour to eliminate the residual stress, structure and phase inhomogeneity caused by the deformation history; the slab is subjected to rolling deformation with a deformation amount of 50%; the cold-rolled slab is used Wash with acetone to remove oil stains on the surface of the slab; heat-treat the cold-rolled slab, the heat treatment system is: 985°C for 1h, and quickly cool under the protection of vacuum argon; /h cooling to 620°C for 8h, rapid cooling under vacuum protection of argon.

As shown in Figure 1, it can be seen from the scanning electron microscope of the GH4169 alloy that evenly distributed granular δ phases are precipitated in the alloy grain boundaries and intragranular structures.

The results of the examples show that when the granular δ phase is evenly distributed in the alloy grain boundary and in the grain, the crack growth rate can be effectively reduced, thereby improving the durability fatigue performance of the material.

Claims (3)

1. the equally distributed GH4169 alloy preparation method of particulate state δ phase; it is characterized in that; comprise cold deformation and the thermal treatment of GH4169 alloy; first to the slab after solid solution carry out more than 30% cold roller and deformed; cool fast under the argon shield of 985 DEG C ± 5 DEG C insulation 1h final vacuums again; then the process of standard double aging is carried out to slab, finally obtain in GH4169 alloy crystal boundary and the equally distributed particulate state δ phase of intracrystalline.

2. according to the equally distributed GH4169 alloy preparation method of particulate state δ phase according to claim 1, it is characterized in that, cold deformation and the thermal treatment of GH4169 alloy comprise the steps:

A) 985 DEG C ± 5 DEG C insulation 1h solution treatment is carried out to GH4169 plate;

B) rolling deformation that deflection is more than 30% is carried out to slab;

C) the slab alcohol after cold deformation or acetone are cleaned;

D) heat-treat cold deformation slab, heat treating regime is: 985 DEG C ± 5 DEG C insulation 1h, cool under vacuum argon shield fast;

E) double aging process is carried out to slab: 720 DEG C ± 5 DEG C insulation 8h, be cooled to 620 DEG C ± 5 DEG C insulation 8h with 50 DEG C/h, cool fast under vacuum argon shield.

3., according to the equally distributed GH4169 alloy preparation method of particulate state δ phase according to claim 2, it is characterized in that, deflection slab being rolled to distortion is preferably 40 ~ 70%.