阅读说明：本技术 一种使用增材制造技术制备镍基合金定向双晶的方法 (Method for preparing nickel-based alloy directional twins by using additive manufacturing technology ) 是由 杨义 杨梦梦 胡嘉南 吴松全 侯娟 林坤 王皞 于 2021-07-21 设计创作，主要内容包括：本发明公开了一种使用增材制造技术制备镍基合金定向双晶的方法,该方法采用电子束、电弧或激光熔丝增材制造技术,其步骤包括：设计所需制备的镍基合金定向双晶的三维几何模型；将镍基合金定向双晶的三维几何模型进行处理,并导入到增材制造设备的系统中；选用合适尺寸和晶向的两块籽晶,相互紧靠后固定在打印基板上；打印基板与冷却装置安装在一起,通过冷却装置对打印基板进行冷却；选用镍基合金的丝材,并根据丝材的特性设计增材制造的工艺参数；按预定打印路径成形所需的定向双晶。本发明可制备镍基合金的大尺寸定向双晶,节约了双晶的制造周期、节约了成本。(The invention discloses a method for preparing nickel-based alloy directional bicrystal by additive manufacturing technology, which adopts electron beam, electric arc or laser fuse additive manufacturing technology and comprises the following steps: designing a three-dimensional geometric model of the directional twins of the nickel-based alloy to be prepared; processing the three-dimensional geometric model of the nickel-based alloy directional twinkle, and introducing the processed three-dimensional geometric model into a system of additive manufacturing equipment; selecting two seed crystals with proper size and crystal orientation, and fixing the two seed crystals on a printing substrate after the two seed crystals are mutually abutted; the printing substrate and the cooling device are installed together, and the printing substrate is cooled by the cooling device; selecting a nickel-based alloy wire material, and designing the process parameters of additive manufacturing according to the characteristics of the wire material; and forming the required directional double crystals according to a preset printing path. The invention can prepare large-size directional twin crystals of the nickel-based alloy, saves the manufacturing period of the twin crystals and saves the cost.)

1. A method of making a directional twinned nickel-base alloy using additive manufacturing techniques, comprising:

s1, designing a three-dimensional geometric model of the directional twinned nickel-based alloy to be prepared;

s2, processing the three-dimensional geometric model of the nickel-based alloy directional twins, and introducing the processed three-dimensional geometric model into a system of additive manufacturing equipment;

s3, selecting two seed crystals with proper size and crystal orientation, and fixing the two seed crystals on the printing substrate after the two seed crystals are mutually abutted;

s4, the printed substrate is mounted together with a cooling device, and the printed substrate is cooled by the cooling device;

s5, selecting a nickel-based alloy wire material, and designing the process parameters of additive manufacturing according to the characteristics of the wire material;

and S6, forming the required directional double crystal according to the preset printing path.

2. The method for preparing an oriented twinned nickel-base alloy using additive manufacturing techniques as claimed in claim 1, wherein step S6 is further followed by the steps of:

s7, separating the printed directional double crystal from the printing substrate;

and S8, cutting the obtained oriented twins along the vertical plane of the deposition direction, preparing a metallographic sample, and detecting the orientation and orientation difference of the oriented twins by an electron back scattering diffraction method.

3. The method for preparing an oriented twinned nickel-base alloy using additive manufacturing techniques as claimed in claim 1 or 2 wherein in step S3 one of the printed substrates is a flat plate.

4. The method for preparing ni-based alloy directional twins using additive manufacturing technique as claimed in claim 1 or 2, wherein in step S3, one of said printing substrates is a refractory ceramic substrate with a funnel-shaped concave surface, a mounting hole is provided at the bottom center position of said funnel-shaped concave surface, and two seed crystals are abutted against each other and mounted in said mounting hole.

5. The method for preparing the nickel-based alloy oriented twins by using the additive manufacturing technology as claimed in claim 1 or 2, wherein a high temperature resistant ceramic sleeve is fixed on the printing substrate, a seed hole is arranged at the central position of the bottom of the high temperature resistant ceramic sleeve, and two seed crystals are abutted against each other and are arranged in the seed hole.

6. The method for preparing the directional twinned nickel base alloy using the additive manufacturing technique as claimed in claim 1 wherein said cooling means includes a cooling tank having a circulating cooling water inlet and a circulating cooling water outlet, said circulating cooling water inlet having a height less than a height of said circulating cooling water outlet.

7. The method of preparing a nickel-base alloy oriented twinned crystal using additive manufacturing techniques of claim 1, wherein the process parameters in the additive manufacturing include: electron beam, arc or laser power, wire feed rate, and lamination thickness.

Technical Field

The invention relates to the technical field of additive manufacturing, in particular to a method for preparing nickel-based alloy directional twins by using an additive manufacturing technology.

Background

Due to good comprehensive performance and mature preparation process, the nickel-based high-temperature alloy is widely applied to the fields of aviation, aerospace, military and the like. Because the preparation cost of the metal single crystal material is high, the metal polycrystalline material is mainly used in practical application. In a metal polycrystalline material, various defects influencing the service performance exist, wherein a grain boundary is one of the inevitable defects, so that research on the grain boundary is very important for improving the mechanical and chemical properties of the metal. In conventional research, influence of the structure and properties of grain boundaries on macro-and micro-scale properties of materials is often studied using polycrystalline samples. However, due to the interference of factors such as different grain sizes and complex types of grain boundaries in polycrystalline samples, the internal relation between different grain boundaries and properties is difficult to clearly explain in research. Compared with the prior art, the use of the oriented twins with single crystal boundaries is more beneficial to eliminating interference and obtaining experimental results which are easier to analyze.

The metal additive manufacturing technology is typically characterized by die-free forming, and the direction of layered stacking of the additive manufacturing technology based on powder bed or powder feeding/wire is the direction with the largest temperature gradient in the processing process, which is also the reason why columnar crystals are easily generated during metal additive manufacturing. Two seed crystals with different crystal orientations and close together are used as a growth source, and metal powder or wire is used as a crystal material source, so that large-size oriented double crystals growing along the layering direction can be theoretically manufactured.

At present, the metal bicrystal plays a great role in the scientific research of the grain boundary, but the research on the preparation of the metal bicrystal material is very little. The additive manufacturing technology can provide a maximum temperature gradient along the layering and stacking direction, so that a solid-liquid interface is away from seed crystals along the layering direction all the time when the metal is solidified, and the geometric shape of the crystals is not required to be controlled by a mould in the growth process, so that the method can be used for preparing the oriented bicrystals with larger geometric dimension.

Disclosure of Invention

Based on the method, the method for preparing the nickel-based alloy oriented twin crystal by using the additive manufacturing technology has the advantages of short production period and low cost.

A method of making a nickel-base alloy oriented twinned using additive manufacturing techniques, comprising:

s1, designing a three-dimensional geometric model of the directional twinned nickel-based alloy to be prepared;

s2, processing the three-dimensional geometric model of the nickel-based alloy directional twins, and introducing the processed three-dimensional geometric model into a system of additive manufacturing equipment;

s3, selecting two seed crystals with proper size and crystal orientation, and fixing the two seed crystals on the printing substrate after the two seed crystals are mutually abutted;

s4, the printed substrate is mounted together with a cooling device, and the printed substrate is cooled by the cooling device;

s5, selecting a nickel-based alloy wire material, and designing the process parameters of additive manufacturing according to the characteristics of the wire material;

and S6, forming the required directional double crystal according to the preset printing path.

In one embodiment, step S6 is followed by the steps of:

s7, separating the printed directional double crystal from the printing substrate;

and S8, cutting the obtained oriented twins along the vertical plane of the deposition direction, preparing a metallographic sample, and detecting the orientation and orientation difference of the oriented twins by an electron back scattering diffraction method.

In one embodiment, in step S3, one of the printed substrates is a flat plate.

In one embodiment, in step S3, one of the printing substrates is a refractory ceramic substrate with a funnel-shaped concave surface, a mounting hole is provided at the bottom center of the funnel-shaped concave surface, and two seed crystals abut against each other and are mounted in the mounting hole.

In one embodiment, a high-temperature-resistant ceramic sleeve is fixed on the printing substrate, a seed hole is formed in the center of the bottom of the high-temperature-resistant ceramic sleeve, and two seed crystals abut against each other and are installed in the seed hole.

In one embodiment, the cooling device comprises a cooling tank, wherein a circulating cooling water inlet and a circulating cooling water outlet are arranged on the cooling tank, and the height of the circulating cooling water inlet is smaller than that of the circulating cooling water outlet.

In one embodiment, the process parameters in the additive manufacturing include: electron beam, arc or laser power, wire feed rate, and lamination thickness.

The method for preparing the nickel-based alloy directional twin crystal by using the additive manufacturing technology has the following advantages:

1) the invention can prepare large-size directional twin crystals of the nickel-based superalloy.

2) The invention can prepare the oriented twin crystal with the size in the horizontal direction being rapidly amplified.

3) And the additive manufacturing technology is used, so that the manufacturing period is saved, and the cost is saved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a flow chart of a method of the present invention;

FIG. 2 is a state diagram for the preparation of oriented twinned crystals in accordance with an embodiment of the present invention;

FIG. 3 is a view showing a starting state of the oriented twin crystal production according to another embodiment of the present invention;

FIG. 4 is a diagram of an end state of the oriented twin crystal production according to another embodiment of the present invention;

FIG. 5 is a schematic structural view of an enlarged oriented twin crystal metal twin crystal part of the present invention;

fig. 6 is a schematic structural diagram of a printing substrate according to yet another embodiment of the present invention.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The main conception of the invention is as follows: geometric modeling and slicing are carried out on the bicrystal to be grown through software, two seed crystals with specific orientation are closely and adjacently fixed on a printing substrate in a mechanical or metallurgical bonding mode, then a metal wire is melted into liquid drops by using additive manufacturing equipment and accumulated on the seed crystals according to a pre-generated path, and finally the metal bicrystal and the printing substrate are separated to obtain the oriented bicrystal with larger geometric size. The method comprises the steps of using an electron beam, an electric arc or laser used by additive manufacturing equipment as a heat source, using a wire material of a nickel-based alloy as a crystal material source, melting the wire material of the nickel-based alloy into liquid drops, depositing the liquid drops on two adjacent seed crystals fixed on a printing substrate layer by layer according to a preset path, and growing directional nickel-based alloy twins along the seed crystals.

Referring to fig. 1, 2 and 5, an embodiment of the present invention provides a method for preparing a nickel-based alloy oriented twin crystal using an additive manufacturing technique, including:

and S1, designing a three-dimensional geometric model of the oriented twins of the nickel-based alloy to be prepared.

S2, processing the three-dimensional geometric model of the nickel-based alloy directional twins, and introducing the three-dimensional geometric model into a system of additive manufacturing equipment; in this embodiment, the energy source used by the additive manufacturing apparatus may be an electron beam, an arc, a laser, or the like.

S3, selecting two seed crystals with proper size and crystal orientation, and fixing the two seed crystals on the printing substrate 1 after the two seed crystals are mutually abutted; in this embodiment, the two seed crystals may include the a seed crystal 2 and the B seed crystal 3 which are closely adjacent to each other.

S4, mounting the printed substrate 1 and the cooling device 6 together, and cooling the printed substrate 1 through the cooling device 6; in this embodiment, the thermal conductivity of the printing substrate 1 is required to be good, so that heat can be dissipated in time during printing.

S5, selecting a nickel-based alloy wire 4, and designing additive manufacturing process parameters according to the characteristics of the wire 4; in this embodiment, the process parameters in the additive manufacturing include: laser power, wire feed rate, lamination thickness, etc.

S6, forming the desired oriented bimorph 7 according to the predetermined print path.

Specifically, the step S6 is followed by the step of:

s7, separating the printed directional double crystal 7 from the printing substrate 1; the separation method may be cutting separation, slight mechanical knocking, or the like, which does not damage the print substrate 1, and the print substrate 1 may be recycled.

And S8, cutting the obtained oriented twins 7 along the vertical plane of the deposition direction, preparing a metallographic sample, and detecting the orientation and orientation difference of the oriented twins by an electron back scattering diffraction method.

In an embodiment of the present invention, in the step S3, one of the printing substrates 1 is a flat plate. Thus, the surface of the printing substrate 1 can be ensured to be flat, and the printing of the bicrystal metal part 7 is facilitated.

In another embodiment of the present invention, referring to fig. 3-4, in step S3, one of the printing substrates 1 is a refractory ceramic substrate with a funnel-shaped concave surface, a mounting hole 10 is formed at the center of the bottom of the funnel-shaped concave surface, and two seed crystals (a seed crystal 2 and B seed crystal 3) are abutted against each other and mounted in the mounting hole 10. In this embodiment, the tapered concave surface is processed on the print substrate 1, which can be used to prepare a metal bimorph in which the vertical dimension and the horizontal dimension are simultaneously enlarged, and can realize the reuse of the print substrate 1. It should be noted that the taper of the funnel-shaped concave surface must be ensured to meet the motion requirements of the additive manufacturing equipment, and the wire feeder 5 does not collide with the funnel-shaped concave surface when printing one circle of the cladding channel with the maximum diameter of each layer.

It should be noted that the printing substrate 1 in this embodiment is required to have good thermal conductivity, to prevent local melting during printing, and to prevent the material of the printing substrate 1 from reacting with the printed metal during printing. In order to ensure the direction of the maximum temperature gradient during printing, all the printing substrates 1 need to be provided with cooling water channels for introducing cooling liquid.

In another embodiment of the present invention, referring to fig. 6, a high temperature resistant ceramic sleeve 8 is fixed on the printing substrate 1, a seed hole 9 is provided at the bottom center position of the high temperature resistant ceramic sleeve 8, and two seed crystals (a seed crystal 2 and B seed crystal 3) are closely attached to each other and mounted in the seed hole 9. In the embodiment, the funnel-shaped concave part is made into the high-temperature-resistant ceramic sleeve 8 with the flange, the embedded blocks with different horizontal amplification speeds can be manufactured by changing the taper, and the corresponding high-temperature-resistant ceramic sleeve 8 can be replaced if necessary, so that the whole printing substrate 1 can be prevented from being replaced, the growth requirements of metal bicrystals with multiple specifications can be met, and the manufacturing and using cost of the printing substrate 1 is reduced again while the printing substrate 1 is recycled.

In an embodiment of the present invention, the cooling device 6 includes a cooling tank 61, the cooling tank 61 is provided with a circulating cooling water inlet 62 and a circulating cooling water outlet 63, and the height of the circulating cooling water inlet 62 is smaller than the height of the circulating cooling water outlet 63.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-described examples merely represent several embodiments of the present application and are not to be construed as limiting the scope of the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.