CN115491621B - Method for optimizing grain boundary precipitated phase of GH3128 high-temperature alloy component - Google Patents

Abstract

The invention provides a method for optimizing a grain boundary precipitated phase of a GH3128 superalloy component, and relates to the technical field of superalloy tissue regulation. The method for optimizing the grain boundary precipitation phase of the GH3128 superalloy component comprises the following steps: reserving 10-20% of deformation of the GH3128 high-temperature alloy component before final forming to obtain an intermediate component; carrying out solid solution treatment on the intermediate member to obtain a solid solution member; and carrying out cold deformation on the solid solution component to finish the residual deformation. The invention carries out 10-20% cold deformation before final forming, the cold deformation degree is smaller, the recrystallization process is not promoted, and as the local crystal grain distortion deformation zone remains in the cold deformation process, the precipitation of the second phase mu phase on the deformation zone can be promoted, and the newly precipitated mu phase can be precipitated along the nucleation position of the deformation zone with larger probability in subsequent high-temperature service or processing, thereby avoiding the continuous distribution of the mu phase along the crystal boundary.

Description

A Method for Optimizing Precipitated Phases at Grain Boundary of GH3128 Superalloy Components

technical field

The invention relates to the technical field of microstructure regulation of superalloys, in particular to a method for optimizing grain boundary precipitated phases of GH3128 superalloy components.

Background technique

GH3128 superalloy is a solid solution strengthened superalloy with nickel base and W, Mo, Al, Zr and other elements as solid solution elements. Due to the high content of alloy elements, it has good plasticity, oxidation resistance and creep resistance. Durability and weldability, as a high-temperature alloy that can work at 950°C for a long time, it is often used in the manufacture of aero-engine flame tubes, power combustion chamber shells, tail nozzles, radiators and other components.

It is precisely because of the high content of GH3128 alloy elements that some intermetallic compounds such as W and Mo have high stability. After serving at high temperature for a period of time, these solid-solution alloy elements will appear to be precipitated from the matrix, such as forming μ equivalent compounds. For example, the precipitation and growth of the second phase μ phase precipitated along the grain boundary during the long-term service at 700-1100 °C is typically reported. This precipitation process, on the one hand, reduces the solid solubility of alloying elements in the nickel-based matrix and reduces On the other hand, it is more important because the precipitation positions of these alloy elements are often selective, and they are all selected in the grain boundary area with more suitable energy conditions, which results in the formation of continuous grain boundaries. The precipitated second phase leads to the weakening of the grain boundary during high-temperature service, which in turn leads to the intergranular cracking of cracks along the grain boundary, forming a more dangerous brittle fracture phenomenon.

Contents of the invention

The purpose of the present invention is to provide a method for optimizing the grain boundary precipitation phase of GH3128 superalloy components, which can effectively avoid the continuous precipitation of the second phase along the grain boundaries of GH3128 superalloy components during subsequent service and thermal processing.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

The invention provides a method for optimizing the grain boundary precipitated phases of GH3128 superalloy components, comprising the following steps: reserving 10-20% deformation of GH3128 superalloy components before final molding to obtain intermediate components; Perform solution treatment to obtain a solution component; cold deform the solution component to complete the remaining deformation.

Preferably, the temperature of the solution treatment is 1100-1200°C.

Preferably, the holding time of the solution treatment is 30-120 minutes.

Preferably, the strain rate of the cold deformation is 0.01-0.1s ^-1 .

Preferably, the GH3128 superalloy member is an annular member.

Preferably, the GH3128 superalloy component is reserved with a deformation amount of 12-18% before final forming.

Preferably, before the cold deformation, the temperature of the solid solution component is lower than 700°C.

The invention provides a method for optimizing the grain boundary precipitated phases of GH3128 superalloy components, comprising the following steps: reserving 10-20% deformation of GH3128 superalloy components before final molding to obtain intermediate components; Perform solution treatment to obtain a solution component; cold deform the solution component to complete the remaining deformation.

The conventional preparation process of GH3128 superalloy components is to perform solution treatment after the deformation is completed, and its structure obtains a structure with relatively balanced energy. In the subsequent high-temperature service process, the second phase μ phase will choose the crystal with the highest energy The continuous precipitation of the grain boundary leads to the weakening of the grain boundary. However, the present invention has carried out 10-20% cold deformation before the final molding, and the degree of cold deformation is small, and will not promote the process of recrystallization, because there are local grain distortion deformation bands left in the cold deformation process, that is, a large number of dislocations The area where defects accumulate will promote the precipitation of the second phase μ phase on the deformation band. During subsequent high-temperature service or processing, the newly precipitated μ phase will have a higher probability of precipitation along the nucleation position of the deformation band, thereby avoiding Continuous distribution of μ phase along grain boundaries.

Description of drawings

Fig. 1 is the microstructure and fracture morphology of the GH3128 ring forging prepared under the conventional process in Comparative Example 1;

Fig. 2 is the microstructure and fracture morphology of the GH3128 ring forging prepared in Example 1;

Fig. 3 is the microstructure and fracture morphology of the GH3128 ring forging prepared in Example 2;

Fig. 4 is a graph comparing the tensile stress-strain curves of the GH3128 ring forgings prepared in Comparative Example 1 and Examples 1-2.

Detailed ways

The invention provides a method for optimizing the grain boundary precipitated phases of GH3128 superalloy components, comprising the following steps: reserving 10-20% deformation of GH3128 superalloy components before final molding to obtain intermediate components; Perform solution treatment to obtain a solution component; cold deform the solution component to complete the remaining deformation.

The present invention has no special requirements on the forming process and conditions of the intermediate member, and the forming process well known in the art can be adopted according to the characteristics of the member. In the present invention, when the GH3128 superalloy member is an annular member, the forming process of the intermediate member preferably includes: preheating the GH3128 superalloy at 1120-1150°C, punching holes after the member is fully heated, and upsetting , and then ring rolling, stop deformation when the temperature is lower than 850°C, reheat to 1120-1150°C and ring-roll and expand the hole again until 10-20% of the deformation is reserved compared with the final formed ring member. The present invention has no special requirements on the preheating time, and the preheating time well known in the art can be used.

After the intermediate member is obtained, the present invention performs solid solution treatment on the intermediate member to obtain a solid solution member. In the present invention, the solution treatment temperature is preferably 1100-1200°C, more preferably 1050-1200°C; the holding time is preferably 30-120min, more preferably 40-100min, and even more preferably 60-90min. The present invention utilizes solid solution treatment to eliminate as much as possible the μ phase precipitated along the grain boundary during the aforementioned deformation process to obtain a complete solid solution component.

After the solid solution component is obtained, the present invention performs cold deformation on the solid solution component to complete the remaining deformation. In the present invention, the strain rate of the cold deformation is preferably 0.01-0.1 s ^-1 , more preferably 0.03-0.08 s ^-1 , even more preferably 0.04-0.06 ^-1 .

In the present invention, before the cold deformation, the temperature of the solid-solution member is preferably lower than 700° C. (that is, lower than the precipitation temperature of μ phase), more preferably room temperature.

The present invention completes the forming of the GH3128 superalloy component through the cold deformation of the last 10-20% of the size, and introduces a large amount of distortion energy in the cold deformation process, so that in the subsequent service or heat treatment process, the precipitation position of the μ phase is not only at the grain boundary , can also be precipitated on some deformed strips, thereby alleviating the damage of the continuous precipitation of μ phase at the grain boundary to the toughness.

The method for optimizing the grain boundary precipitated phase of the GH3128 superalloy component provided by the present invention will be described in detail below in conjunction with the examples, but they should not be understood as limiting the protection scope of the present invention.

Comparative example 1

Heat the GH3128 high-temperature alloy forging billet to 1130±10°C, then punch through, upsetting, and then ring-roll, stop deformation when the temperature is lower than 850°C, then heat to 1130±10°C, continue ring-rolling, and finally Solution treatment was carried out at 1200°C for 100 minutes to obtain solid solution state GH3128 ring forging.

Example 1

Heat the GH3128 high-temperature alloy forging billet to 1130±10°C and then punch through, upsetting, and then ring rolling. When the temperature is lower than 850°C, stop deformation, and then reheat to 1130±10°C, continue ring rolling, reserve 10% deformation, get the intermediate member;

The intermediate member is kept at 1200°C for 100 minutes for solution treatment to obtain a solution member;

After the solid solution component is cooled to room temperature, it is deformed at a strain rate of 0.1 s ^-1 , that is, ring rolling is completed by cold deformation, and a GH3128 ring forging is obtained.

Example 2

The only difference from Embodiment 1 is that 20% of deformation is reserved.

Structure Characterization:

1. The microstructure of the solid solution GH3128 ring forging of Comparative Example 1 was observed, and the results are shown in Figure 1. (a) in Figure 1 is the microstructure, (b) in Figure 1 is observed under a larger magnification with a significant distribution of the second phase along the grain boundary, (c) in Figure 1 is the tensile fracture, due to the cooling process μ phase along The grain boundary is precipitated, and the fracture of the tensile sample in the mechanical property test is obviously an intergranular fracture.

2. Observing the microstructure of the GH3128 ring forging prepared in Example 1, the results are shown in Figure 2. From Figure 2 (a), it can be seen that the grains are equiaxed, but a large number of second phases are precipitated along the direction of the deformed strips, as shown in Figure 2. (b) in 2 is a partial enlarged picture of (a). It can be seen that there are a small amount of grain distribution on the grain boundary, but most of the grains are not on the grain boundary. Compared with the grain boundary in Figure 1, the grain boundary is significantly thinner, indicating that there is no second phase The continuous precipitation on the grain boundary leads to the coarsening of the grain boundary. Figure 2 (c) is a tensile fracture diagram. It can be observed that the secondary cracks are significantly reduced, and the fracture is no longer flat, with significant plastic deformation traces, which shows that After the treatment, the continuous precipitation of the μ phase on the grain boundary is prevented from weakening the grain boundary, and the continuous expansion of cracks along the weakened grain boundary is prevented. Therefore the forging that is finished by the inventive method, the tensile property strong plasticity of sample improves significantly, as shown in Figure 4, the solid solution state GH3128 ring forging tensile strength of comparative example 1 is 734MPa, and elongation is 53% ; The tensile strength of the GH3128 ring forging of Example 1 is 786MPa, and the elongation is 78%.

3. Observing the microstructure of the GH3128 ring forging prepared in Example 2, the results are shown in Figure 3. From Figure 3, it can be seen that the increase in the degree of cold deformation leads to an increase in the density of precipitated particles in the deformed strip, and in (a) along the The number of deformed strips has increased compared with that in Example 1, (b) is a partial enlarged view, the grain boundaries are finer, the second phase precipitates are very few, and no continuous second phase is seen. (c) shows that at the tensile fracture, there is almost no intergranular smooth brittle fracture, and the plastic deformation dimples on the fracture are obvious. The residual deformation of this embodiment is relatively large, so its plastic index is reduced, as shown in Figure 4, the tensile strength is 756MPa, and the elongation is 67%, which is lower than that of Example 1, but still higher than that of Comparative Example 1 .

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (3)

1. A method for optimizing the grain boundary precipitated phase of GH3128 superalloy component, is characterized in that, comprises the following steps: GH3128 superalloy component is reserved 10～20% deformation before final forming, obtains intermediate component; The intermediate member is subjected to solution treatment to obtain a solution member; the solution member is subjected to cold deformation to complete the remaining deformation; the temperature of the solution treatment is 1100~1200°C; the holding time of the solution treatment is 30~120min; the strain rate of the cold deformation is 0.01~0.1s ^-1 ; before the cold deformation, the temperature of the solid solution component is lower than 700°C. 2. The method according to claim 1, characterized in that, the GH3128 superalloy member is an annular member. 3. The method according to claim 1, characterized in that, the GH3128 superalloy component is reserved with a deformation amount of 12-18% before final forming.

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