阅读说明：本技术 含层错与γ′相复合结构的镍基合金及其制备方法 (Nickel-based alloy containing stacking fault and gamma' phase composite structure and preparation method thereof ) 是由 张勇 董巍 袁圣云 冯天 尤泽升 于 2019-02-26 设计创作，主要内容包括：本发明涉及纳米结构金属材料技术领域,具体涉及一种含高强度高热稳定性的层错与γ′相复合结构的镍基合金及其制备方法。镍基合金表层的组织结构为层错与γ′相的复合结构,所述层错为高密度层错,高密度层错交割结构设置在γ′相中,形成层错与γ′相复合结构。该方法是先后利用表面机械滚压处理和时效处理对镍基合金进行处理,从而在镍基合金表层制备出高密度层错与γ′相的复合结构。所述复合结构中层错间距分布在5～25nm,γ′相尺寸分布在30～80nm。该结构的微观硬度在6.0-7.0GPa之间,微观硬度是表面处理前镍基合金的1.2-1.8倍,结构粗化温度比纳米晶镍基合金高30-80℃,大大提高了镍基合金具有高强度高热稳定性。(The invention relates to the technical field of nano-structure metal materials, in particular to a nickel-based alloy containing a high-strength high-thermal-stability laminated structure and a gamma' phase composite structure and a preparation method thereof. The texture structure of the surface layer of the nickel-based alloy is a composite structure of a stacking fault and a gamma ' phase, the stacking fault is a high-density stacking fault, and a high-density stacking fault intersection structure is arranged in the gamma ' phase to form the composite structure of the stacking fault and the gamma ' phase. The method is characterized in that the nickel-based alloy is treated by successively utilizing surface mechanical rolling treatment and aging treatment, so that a high-density fault and gamma' phase composite structure is prepared on the surface layer of the nickel-based alloy. The staggered spacing of the layers in the composite structure is 5-25nm, and the size of the gamma' phase is 30-80 nm. The micro-hardness of the structure is between 6.0 and 7.0GPa, the micro-hardness is 1.2 to 1.8 times that of the nickel-based alloy before surface treatment, the coarsening temperature of the structure is 30 to 80 ℃ higher than that of the nanocrystalline nickel-based alloy, and the high strength and high thermal stability of the nickel-based alloy are greatly improved.)

1. The nickel-based alloy containing the composite structure of the stacking faults and the gamma 'phase is characterized in that the tissue structure of the surface layer of the nickel-based alloy is the composite structure of the stacking faults and the gamma' phase, the stacking faults are high-density stacking faults, and a high-density stacking fault intersecting structure is arranged in the gamma 'phase to form the composite structure of the stacking faults and the gamma' phase, so that the nickel-based alloy has high strength and high thermal stability.

2. The nickel-based alloy according to claim 1, wherein the dislocation pitch of the composite structure of the stacking faults and the gamma ' phase is distributed between 5nm and 25nm, the size of the gamma ' phase is distributed between 30 nm and 80nm, and the thickness of the composite structure of the stacking faults and the gamma ' phase on the surface layer of the nickel-based alloy is 100 μm and 200 μm.

3. The nickel-base alloy of claim 1, wherein the composition of the nickel-base alloy is, in atomic percent (at.%): 46.50-48.50% of Ni, 22.94-25.14% of Co, 14.36-15.46% of Cr, 5.10-6.20% of Al, 4.05-4.97% of Ti, 1.82-2.70% of Mo, 0.24-0.34% of W, 0.50-0.62% of Fe, 0.02-0.05% of Zr, 0.07-0.11% of C and 0.06-0.07% of B.

4. A method for preparing the nickel-base alloy according to any of claims 1 to 3, characterized by the following specific steps:

(1) carrying out solution treatment on the nickel-based alloy to obtain the nickel-based alloy with a high-density gamma' phase strengthened gamma matrix structure;

(2) the surface mechanical rolling treatment is utilized to process the nickel-based alloy with the high-density gamma 'phase strengthened gamma matrix structure, and a high-density fault intersected structure is obtained on the surface layer of the nickel-based alloy, wherein the fault structure destroys the gamma' phase L1₂An ordering structure;

(3) the nickel base alloy in the step (2) is aged, and gamma' phase L1₂And recovering the ordered structure again to finally obtain the nickel-based alloy containing the composite structure of the stacking fault and the gamma' phase.

5. The method according to claim 4, wherein the surface mechanical rolling treatment is performed by using a surface mechanical rolling treatment system, the surface mechanical rolling treatment system comprises a treatment tool and a cooling system, the surface layer of the nickel-based alloy is subjected to the mechanical rolling treatment by using the treatment tool, and the temperature of the surface of the sample in the mechanical rolling treatment is reduced by using the cooling system.

6. The method according to claim 5, wherein the tool bit part of the processing tool is a cemented carbide ball which is made of WC-Co alloy and has a diameter of 4-10 mm; the cooling system is cooled in a liquid nitrogen atmosphere.

7. The method according to claim 6, wherein the nickel-based alloy is in the shape of a rod, and the surface mechanical rolling treatment is specifically: the rod-shaped nickel-based alloy rotates along the self axial direction, a hard alloy ball of the processing cutter is in contact with the surface of the nickel-based alloy and pressed into the nickel-based alloy to a certain depth, the processing cutter is fed and moves from one end of the workpiece to the other end along the surface of the rod-shaped nickel-based alloy, and one pass processing is completed; after the above process is repeated for a plurality of times, a plastic deformation layer is formed on the surface of the nickel-based alloy; the depth of the hard alloy ball pressed into the surface of the nickel-based alloy is determined according to the thickness of the composite structure surface layer of the stacking fault and the gamma' phase of the nickel-based alloy to be processed.

8. The method as claimed in claim 7, wherein the diameter of the rod-shaped nickel-based alloy is 8-15mm, the rotating speed of the rod-shaped nickel-based alloy in the axial direction is 100-800r/min, the feeding speed of the processing tool along the axial direction of the rod-shaped nickel-based alloy is 40-80mm/min, the reduction depth of the hard alloy ball on the surface of the nickel-based alloy in each processing pass is 20-80 μm, and the processing pass is 1-10.

9. The method according to claim 4, characterized in that the aging treatment in step (3) is performed by using a box-type electric furnace, specifically: and (3) heating the box type electric furnace to a preset aging temperature, then putting the nickel-based alloy subjected to surface treatment into the furnace, preserving heat, taking out the sample, and naturally cooling the sample in the air.

10. The method as claimed in claim 9, wherein the aging temperature is 600-800 ℃, and the holding time for holding is 25-100 h.

Technical Field

The invention relates to the technical field of nano-structure metal materials, in particular to a nickel-based alloy containing a high-strength high-thermal-stability laminated structure and a gamma' phase composite structure and a preparation method thereof.

Background

The nickel-based alloy has good oxidation resistance and certain corrosion resistance, and is widely applied to the industrial fields of aerospace, mechanical manufacturing and the like. The nickel base alloy has larger grains in the initial structure and lower strength. Therefore, in order to improve the strength of the nickel-based alloy, material scientists have made several centuries of effort to provide methods such as solid solution strengthening, second phase strengthening and plastic deformation strengthening. The strength of the alloy can be obviously improved by using a solid solution strengthening method and a second phase strengthening method, but the physical and chemical properties of the material are changed by adding alloy elements.

In addition, by plastic deformation, defects (e.g., grain boundaries, dislocations) can be introduced into the material to increase its strength, which does not change the chemical composition of the material as compared to solution treatment and second phase strengthening, but the resulting material is generally less plastic and thermally stable. The documents Sun Y, Xu S, Shann A. effects of influencing on microstructure and technical properties of nano-grained Ni-based alloy by way of rolling [ J ] Materials Science & Engineering A,2015,641: 181-. However, after the cold-rolled nanocrystalline nickel-based alloy is annealed at 700 ℃ and 800 ℃ for 1 hour, the average size of nanocrystalline grains is 90nm and 200nm, and the nanocrystalline grains grow obviously, which proves that the nanocrystalline nickel-based alloy has poor thermal stability.

The Liu Xiaochun et al, Liu X C, Zhang H W, Lu K, Strain-induced ultra-hard and ras table based engineered structure in nickel [ J ] Science,2013,342(6156) 337-340, mentioned in Liu Xiaochun et al, by surface mechanical milling treatment in pure nickel to induce high speed shear deformation to prepare a new nano lamellar structure. The thickness of the lamellar is between 5nm and 50nm, the hardness is as high as 6.4GPa, the coarsening temperature of the lamellar structure is 506 ℃, and is 40 ℃ higher than that of steady-state ultrafine crystal nickel (466 ℃). The nano lamellar structure prepared by the method improves the strength and the thermal stability of the material to a certain extent, but the improvement range is lower.

The gradient structure which is currently in great interest can also enable the metal material to obtain good strength and stability. By performing shot blasting or the like on the surface of the rod-shaped metal, a gradient structure is obtained in which the core coarse crystals gradually transition to the surface layer nanocrystals. The structure realizes that the yield strength of the coarse-grain pure copper material is improved by 2 times, and meanwhile, the plasticity and the stability of the coarse-grain pure copper material are hardly lost. And the mechanical properties of the metal material can be adjusted by changing the volume percentage of the gradient layer, but as the percentage of the gradient layer increases, the strength increases but the plasticity and thermal stability decreases. Therefore, although this method improves the strength of the metal material, it is difficult to maintain good plasticity and thermal stability when the metal material attains high strength.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a nickel-based alloy containing a composite structure of a stacking fault and a gamma 'phase and a preparation method thereof, wherein the nickel-based alloy has high strength and high thermal stability through the composite structure of the stacking fault and the gamma' phase.

The technical solution for realizing the purpose of the invention is as follows:

the tissue structure of the surface layer of the nickel-based alloy is a composite structure of the stacking faults and the gamma ' phase, the stacking faults are high-density stacking faults, and a high-density stacking fault intersecting structure is arranged in the gamma ' phase to form the composite structure of the stacking faults and the gamma ' phase, so that the nickel-based alloy has high strength and high thermal stability.

Furthermore, the dislocation space in the composite structure of the stacking faults and the gamma ' phase is distributed between 5nm and 25nm, the size of the gamma ' phase is distributed between 30 nm and 80nm, and the thickness of the composite structure of the stacking faults and the gamma ' phase on the surface layer of the nickel-based alloy is 100-200 mu m.

Further, the nickel-base alloy has the following composition in atomic percent (at.%): 46.50-48.50% of Ni, 22.94-25.14% of Co, 14.36-15.46% of Cr, 5.10-6.20% of Al, 4.05-4.97% of Ti, 1.82-2.70% of Mo, 0.24-0.34% of W, 0.50-0.62% of Fe, 0.02-0.05% of Zr, 0.07-0.11% of C and 0.06-0.07% of B.

The method for preparing the nickel-based alloy comprises the following specific steps:

(1) carrying out solution treatment on the nickel-based alloy to obtain the nickel-based alloy with a high-density gamma' phase strengthened gamma matrix structure;

(2) the surface mechanical rolling treatment is utilized to process the nickel-based alloy with the high-density gamma 'phase strengthened gamma matrix structure, and a high-density fault intersected structure is obtained on the surface layer of the nickel-based alloy, wherein the fault structure destroys the gamma' phase L1₂An ordering structure;

(3) the nickel base alloy in the step (2) is aged, and gamma' phase L1₂And recovering the ordered structure again to finally obtain the nickel-based alloy containing the composite structure of the stacking fault and the gamma' phase.

Further, the surface mechanical rolling treatment adopts a surface mechanical rolling treatment system, the surface mechanical rolling treatment system comprises a treatment cutter and a cooling system, the treatment cutter is used for carrying out mechanical rolling treatment on the surface layer of the nickel-based alloy, and the cooling system is used for reducing the temperature of the surface of the sample in the mechanical rolling treatment.

Further, the cutter head part of the processing cutter is a hard alloy ball, the hard alloy ball is made of WC-Co alloy, and the diameter of the hard alloy ball is 4-10 mm; the cooling system is cooled in a liquid nitrogen atmosphere.

Further, the shape of the nickel-based alloy is a rod, and the mechanical surface rolling treatment specifically comprises the following steps: the rod-shaped nickel-based alloy rotates along the self axial direction, a hard alloy ball of the processing cutter is in contact with the surface of the nickel-based alloy and pressed into the nickel-based alloy to a certain depth, the processing cutter is fed and moves from one end of the workpiece to the other end along the surface of the rod-shaped nickel-based alloy, and one pass processing is completed; after the above process is repeated for a plurality of times, a plastic deformation layer is formed on the surface of the nickel-based alloy; the depth of the hard alloy ball pressed into the surface of the nickel-based alloy is determined according to the thickness of the composite structure surface layer of the stacking fault and the gamma' phase of the nickel-based alloy to be processed.

Further, the diameter of the rod-shaped nickel-based alloy is 8-15mm, the rotating speed of the rod-shaped nickel-based alloy in the axial direction is 100-800r/min, the feeding speed of the treatment cutter along the axial direction of the rod-shaped nickel-based alloy is 40-80mm/min, the pressing depth of the hard alloy ball on the surface of the nickel-based alloy in each treatment pass is 20-80 mu m, and the processing pass is 1-10.

Further, the aging treatment in the step (3) adopts a box-type electric furnace, and specifically comprises the following steps: and (3) heating the box type electric furnace to a preset aging temperature, then putting the nickel-based alloy subjected to surface treatment into the furnace, preserving heat, taking out the sample, and naturally cooling the sample in the air.

Further, the aging temperature is 600-800 ℃, and the heat preservation time is 25-100 h.

Compared with the prior art, the invention has the following remarkable advantages:

(1) the invention utilizes the method of combining the surface mechanical rolling treatment and the aging treatment to obtain a composite structure of the stacking fault and the gamma' phase on the surface of the nickel-based alloy, wherein the surface mechanical rolling treatment is used for obtaining a high-density stacking fault intersecting structure on the surface of the nickel-based alloy, the strengthening mechanism can be explained by using Hall-Petch relation, and the strength of the nickel-based alloy is obviously improved because the spacing of the stacking fault is only a few nanometers. And the gamma 'phase of the ordered structure is restored through aging treatment, so that the resistance of the stacking fault movement is further increased, and the strength and the thermal stability of the nickel-based alloy are remarkably improved through the composite structure of the stacking fault and the gamma' phase.

(2) The method is characterized in that a laminated fault and gamma ' phase composite structure is prepared in the nickel-based alloy through surface mechanical rolling treatment and aging treatment, and deformation process parameters are easy to control in the surface mechanical rolling treatment process, so that the thickness of a laminated fault and gamma ' phase composite structure area can be controlled by combining the characteristics of a base material and optimizing various parameters, cutter parameters and the like in the surface mechanical treatment process, and high strength and high thermal stability of the laminated fault and gamma ' phase composite structure area can be still maintained when a thin deformation layer is prepared on the surface of the nickel-based alloy.

(3) The surface mechanical rolling treatment method of the invention prepares a composite structure of the stacking fault and the gamma' phase with a certain thickness on the surface layer of the nickel-based alloy, which is different from a uniform structure material prepared by the traditional method. The invention improves the strength and the thermal stability of the nickel-based alloy by only changing the microstructure on the premise of not changing the chemical components of the material. And the aging treatment can flexibly change the aging temperature and time, and is easy to control the size of the gamma' phase, thereby ensuring that the performance of the nickel-based alloy reaches the optimum.

The present invention is described in further detail below with reference to the attached drawing figures.

Drawings

Fig. 1 is a high-resolution transmission electron microscope image of a composite structure of a stacking fault and a γ' phase in the nickel-based alloy in example 1.

Fig. 2 is a high-resolution transmission electron microscope image of a composite structure of a stacking fault and a γ' phase in the nickel-based alloy in example 2.

Fig. 3 is a high-resolution transmission electron microscope image of a composite structure of a stacking fault and a γ' phase in the nickel-based alloy in example 3.

FIG. 4 is a comparison of the micro-hardness of the nickel-base alloys of examples 1, 2, and 3 and the micro-hardness of the prior art nickel-base alloy.

Detailed Description

A preparation method of a nickel-based alloy containing a composite structure of a stacking fault and a gamma 'phase is provided, and the composite structure of the stacking fault and the gamma' phase has high strength and high thermal stability. Firstly, the nickel-based alloy is subjected to solution treatment to obtain a high-density gamma' phase strengthened gamma matrix structure. Then mechanically rolling the surface of the high-density gamma '-phase strengthened nickel-based alloy to obtain a high-density fault intersected structure on the surface layer, wherein the fault intersected structure breaks the gamma' -phase L1₂Ordering the structure, then carrying out aging treatment on the nickel-based alloy, wherein the gamma' phase is L1₂And the ordered structure is restored again, and finally a structure with the composite of the stacking fault and the gamma' phase is obtained, and the structure remarkably improves the strength and the thermal stability of the nickel-based alloy.

The dislocation space of the composite structure of the stacking faults and the gamma 'phase is distributed in the range of 5-25nm, and the size of the gamma' phase is distributed in the range of 30-80 nm.

When the nickel-based alloy is subjected to surface plastic deformation by adopting surface mechanical rolling treatment, the surface mechanical rolling treatment system comprises a treatment cutter and a cooling system. The tool bit part of the tool is a hard alloy ball which is made of WC-Co alloy, and the diameter of the hard alloy ball is 4-10 mm. And the cooling treatment process adopts liquid nitrogen atmosphere cooling to reduce the temperature rise of the surface of the sample in the treatment process. For the low-layer fault energy nickel-based alloy, the surface mechanical rolling treatment process does not need cooling, and the room temperature is kept.

The surface mechanical rolling treatment process comprises the following steps: firstly, cutting the nickel-based alloy into a rod shape by utilizing linear cutting, enabling the rod-shaped nickel-based alloy to rotate along the self axial direction, enabling a hard alloy ball of a processing cutter to be in contact with the surface of the nickel-based alloy and pressed into the surface of the nickel-based alloy to a certain depth, and then moving from one end of a workpiece to the other end along the surface of a nickel-based alloy rotating piece to finish one pass processing; after the above process is repeated for a plurality of times, a plastic deformation layer is formed on the surface of the nickel-based alloy; the diameter of the rod-shaped nickel-based alloy is 8-15mm, the rotating speed of the nickel-based alloy rotating member is 800-800 r/min, the feeding speed of the processing cutter along the axial direction of the nickel-based alloy rotating member is 40-80mm/min, the pressing depth of the hard alloy ball cutter head on the surface of the nickel-based alloy in each processing pass is 20-80 mu m, and the processing pass is 1-10.

The aging treatment process comprises the following steps: and (3) heating the box type electric furnace to a preset aging temperature, then putting the nickel-based alloy subjected to surface treatment into the furnace, preserving heat for a certain time, taking out the sample, and naturally cooling the sample in the air.

The aging time is as follows: 25-100h, aging temperature: 600 ℃ and 800 ℃.

The nickel-based alloy with the composite structure of the stacking fault and the gamma' phase has the following properties: the micro hardness of the alloy is 1.2-1.8 times of that of the nickel-based alloy before surface treatment, and the structure coarsening temperature is 30-80 ℃ higher than that of the nanocrystalline nickel-based alloy.