CN109604864B

CN109604864B - Titanium-based solder for connecting TiAl alloy and Ni-based high-temperature alloy

Info

Publication number: CN109604864B
Application number: CN201811365925.0A
Authority: CN
Inventors: 孔见; 董可伟
Original assignee: Nanjing University of Science and Technology
Current assignee: Nanjing University of Science and Technology
Priority date: 2018-11-16
Filing date: 2018-11-16
Publication date: 2021-05-04
Anticipated expiration: 2038-11-16
Also published as: CN109604864A

Abstract

The invention discloses a titanium-based solder for connecting TiAl alloy and Ni-based high-temperature alloy. The brazing filler metal formula comprises the following components: 40-50wt% of Ti, 25-35 t% of Zr, 5-10 wt% of Be, 10-15wt% of Co and 0.1-0.5wt% of Y; the method of smelting and melt spinning is adopted to prepare amorphous strips with the thickness of about 40-50 mu m and the width of about 10 mm. The strip obtained by utilizing the components has superplastic deformation capacity in a wider supercooling liquid phase region range, so that the contact area between the intermediate layer and the base material can be greatly increased; the strength of the obtained welding joint exceeds 300MPa by using the amorphous strip provided by the invention as the intermediate layer.

Description

Titanium-based solder for connecting TiAl alloy and Ni-based high-temperature alloy

Technical Field

The invention relates to a titanium-based brazing filler metal, and belongs to the field of engineering materials.

Background

TiAl（Ti₃Al, TiAlNb) -based intermetallic compound alloy has the characteristics of low density, high elastic modulus, good high-temperature mechanical property, oxidation resistance and the like, and is expected to be widely applied in the fields of aviation, aerospace, military industry and the like. Especially when used as turbine material of engines such as missile, airship, supersonic aircraft and tank, the working performance and service life of the engines can be greatly improved. When the titanium-aluminum alloy is used as an engine material, the titanium-aluminum alloy and the nickel-based superalloy are required to be connected together so as to fully exert the respective excellent performances. The welding connection of the TiAl intermetallic compound alloy is a new problem along with the application research of the TiAl alloy, and from the current domestic and foreign published paper conditions, the connection technology of the TiAl alloy relates to fusion welding (such as arc welding, laser welding, electron beam welding and the like) and solid welding (such as brazing, diffusion welding, self-propagating high-temperature synthesis, friction welding and the like). In fusion welding, due to the difference in physical and chemical properties between Ti, Al and Ni, the joint is prone to generate intermetallic compound brittle phases, so that the joint strength is not high, and in solid-state welding, a long connection time and a large external stress are generally required, which may deform the base material, thereby affecting the joint strength.

Disclosure of Invention

The invention aims to provide a titanium-based solder which has good toughness and relatively low melting point, can be used as a middle layer in TiAl-Ni (such as GH 4049) connection and improves the tensile strength of a joint.

The technical scheme for realizing the purpose of the invention is as follows: the titanium-based brazing filler metal comprises the following components in parts by weight: 40-50wt% of Ti, 25-35 t% of Zr, 5-10 wt% of Be, 10-15wt% of Co and 0.1-0.5wt% of Y.

Further, the melting point of the titanium-based brazing filler metal is 700 +/-5 ℃.

The preparation method of the titanium-based brazing filler metal comprises the following steps: smelting Ti, Zr, Be, Co and Y raw materials into a metal spindle in an electric arc smelting furnace, adopting a rapid cooling technology, reheating the alloy spindle to a molten state in a quartz tube during strip throwing, and spraying the alloy spindle onto a rapidly rotating copper wheel under the action of air pressure difference to obtain the strip.

Furthermore, the purity of the raw materials of Ti, Zr, Be, Co and Y is more than 99.95 percent.

Further, the vacuum degree of induction melting is 10^-3Above MPa, and smelting for at least 3-4 times to ensure uniform structure and no segregation.

Further, the melt-spun adopts an induction heating mode, the length of a gap of a used quartz tube is 10mm, the width of the gap is 0.5mm, the induced current is 17-22A, the air pressure difference is not lower than 0.05MPa, and the drying time is 1 h.

Further, the rapid cooling technology adopts the following process parameters: the protective gas is argon, and the gas pressure is controlled to be 0.5-0.8 MPa; the spraying distance is controlled to be 2-3 mm.

Compared with the prior art, the invention has the advantages that:

(1) the band obtained by using the composition has relatively low melting point, good toughness and larger supercooled liquid phase region.

(2) The strip obtained by utilizing the components has superplastic deformation capacity in a wider supercooling liquid phase region range, so that the contact area between the intermediate layer and the base material can be greatly increased.

(3) The brazing filler metal prepared by the components realizes metallurgical bonding through liquid phase brazing, and is particularly suitable for the welding connection of the titanium-aluminum intermetallic compound and the nickel-based high-temperature alloy.

Detailed Description

To further illustrate the present invention, the following examples are provided to describe the formulation of the present invention, and the method and application of making the tape in detail.

The invention relates to a brazing filler metal formula applied to TiAl and Ni-based high-temperature alloy brazing, which comprises the following components in percentage by weight: 40-50wt% of Ti, 25-35 t% of Zr, 5-10 wt% of Be, 10-15wt% of Co and 0.1-0.5wt% of Y.

The formula material provided by the invention comprises Ti, and the Ti has the advantages of low density, high strength, high temperature resistance, mutual solubility with a parent metal to be welded and the like. The Ti content in the invention is 40-50wt%, preferably 45.7-49 wt%.

The formulation provided in the present invention includes Zr, which promotes interdiffusion between the intermediate layer and the parent material, and the content of Zr is 25-35wt%, preferably 27-33 wt%.

The formula material provided by the invention comprises Be, wherein the Be is an element which can well improve the amorphous forming ability, and the content of the Be is 5-10 wt%, preferably 5.5-8.7 wt%.

The formula material provided by the invention comprises Co, wherein the Co and Ni in the parent metal are ferromagnetic elements, and the addition of Co is beneficial to the mutual diffusion of the intermediate layer and the parent metal according to the similar compatibility principle. The content thereof is 10 to 15wt%, preferably 12 to 15.7 wt%.

The formula material provided by the invention comprises Y, and the Y element can increase the atomic radius difference of an alloy system, so that the forming capability of the amorphous alloy is improved. It is present in an amount of 0.2-0.5 wt.%, preferably 0.3 wt.%.

In the invention, an amorphous strip is prepared by a melt-spinning method after Ti, Zr, Be, Co and Y are subjected to induction melting. When the materials are selected, the purities of Ti, Zr, Be, Co and Y are all more than 99.95 wt.%.

The amorphous strip prepared from the Ti, Zr, Be, Co and Y formula material provided by the invention has a lower melting point and has good strength and toughness in a room temperature environment.

The amorphous strip prepared from the Ti, Zr, Be, Co and Y formula material provided by the invention has a lower melting point, has good toughness and strength in a room temperature environment, has superplastic deformation capability in a wider supercooling liquid phase region, and has a good promotion effect on the mechanical contact stage of the intermediate layer and the base metal.

The present invention provides a method of preparing a tape comprising: melting Ti, Zr, Be, Co and Y raw materials into a metal spindle in an electric arc melting furnace, reheating the alloy spindle to a molten state in a quartz tube by adopting a rapid cooling technology, and spraying the alloy spindle onto a rapidly rotating copper wheel under the action of air pressure difference to obtain the strip. The melt-spun adopts an induction heating mode, the length of a gap of a used test tube is 10mm, the width of the gap is 0.5mm, the induced current is 17-22A of internal and external air pressure difference, the air pressure difference is not less than 0.05Mpa, and the process parameters adopted by the rapid cooling technology are as follows: the protective gas is argon, and the gas pressure is controlled to be 0.5-0.8 MPa; the spraying distance is controlled to be 2-3 mm. The method of smelting and melt spinning is adopted to prepare amorphous strips with the thickness of about 40-50 mu m and the width of about 10 mm.

The brazing filler metal is made into a thin strip shape by vacuum melting and strip casting technology. During brazing, the obtained thin strip is placed between TiAl alloy and Ni-based alloy, and the assembled sample is placed in a vacuum hot pressing furnace at 10 DEG^-3The temperature is increased to 30-50 ℃ above the melting point of the brazing filler metal at the speed of 10 ℃/min under the vacuum degree of Pa, and the temperature is kept for 5-10 min. The strength of the welded joint obtained by experiments can reach 320MPa by using the amorphous strip provided by the invention as the intermediate layer.

Example 1:

smelting Ti, Zr, Be, Co and Y raw materials with the purity of more than 99.95 percent into a metal spindle by an electric arc smelting mode according to 45.7wt percent of Ti, 33wt percent of Zr, 8wt percent of Be, 13wt percent of Co and 0.3wt percent of Y, wherein the smelting frequency is not less than 3-4 times in order to ensure uniform structure. The obtained spindle is placed in a quartz tube and heated to a molten state in an induction heating mode, and liquid metal is sprayed onto a rapidly rotating copper wheel by utilizing the pressure difference between the inside and outside gases, so that an amorphous strip is finally obtained. The vacuum degree in the smelting and strip throwing processes is not lower than 10^-3MPa, argon as protective gas, and 0.5MPa of internal and external pressure difference during melt spinning.

The obtained strip has a width of 9mm and a thickness of 35um, the obtained thin strip is placed between TiAl alloy and Ni-based alloy during brazing, the assembled sample is placed in a vacuum hot pressing furnace at 10 DEG^-3Raising the temperature to 800 ℃ at a speed of 10 ℃/min under the vacuum degree of Pa, and preserving the temperature for 5min-10 min. The strength of the welding joint obtained by the experiment can reach 320 MPa.

The alloy compositions of the examples and the weld joint strengths thereof are shown in tables 1 and 2.

TABLE 1 alloy compositions

Examples	Composition (I)
		1	45.7wt%Ti、33wt%Zr、8wt%Be、13wt%Co，0.3wt%Y
2	46wt%Ti、30wt%Zr、8wt%Be、15.7wt%Co、0.3wt%Y
		3	46.5wt%Ti、30.9wt%Zr、7.8wt%Be、14.5wt%Co、0.3wt%Y
4	47wt%Ti、32wt%Zr、6.5wt%Be、14.2wt%Co、0.3wt%Y、
		5	47.5wt%Ti、33wt%Zr、6wt%Be、13.2wt%Co、0.3wt%Y
6	47.9wt%Ti、31wt%Zr、5.5wt%Be、15.3wt%Co、0.3wt%Y
		7	48.5wt%Ti、32.2wt%Zr、7wt%Be、12wt%Co、0.3wt%Y
8	48.9wt%Ti、30.9wt%Zr、6.9wt%Be、13wt%Co、0.3wt%Y、
		9	49wt%Ti、27wt%Zr、8wt%Be、15.7wt%Co、0.3wt%Y
10	49wt%Ti、28wt%Zr、8.7wt%Be、14wt%Co、0.3wt%Y

TABLE 2 weld joint strength

Examples	Tensile strength of joint (MPa)
		1	320
2	316
		3	324
4	323
		5	322
6	308
		7	310
8	309
		9	290
10	295

The present invention is not limited to the above embodiments, and other component designs obtained by using the same or similar processes and components as those of the above embodiments of the present invention are within the scope of the present invention.

Claims

1. The titanium-based brazing filler metal is characterized in that the formula of the brazing filler metal comprises the following components: 40-50wt% of Ti, 25-35 t% of Zr, 5-10 wt% of Be, 10-15.7 wt% of Co and 0.1-0.5wt% of Y.

2. The brazing filler metal according to claim 1, wherein the Ti content is 45.7wt% to 49 wt%.

3. The brazing filler metal according to claim 1, wherein the Zr content is 27 to 33 wt%.

4. The brazing filler metal according to claim 1, wherein the Be content is 5.5wt% to 8.7 wt%.

5. The solder according to claim 1, wherein the content of Co is 12 to 15.7 wt%.

6. The brazing filler metal according to claim 1, wherein the content of Y is 0.3 wt%.

7. A brazing filler metal according to any one of claims 1 to 6, wherein said titanium-based brazing filler metal has a melting point of 700 ± 5 ℃.

8. A solder according to any of claims 1 to 6, characterized in that the solder is used for joining TiAl alloys with Ni-based superalloys.

9. A method for producing a brazing filler metal according to any one of claims 1 to 8, characterized by the steps of: smelting Ti, Zr, Be, Co and Y raw materials into a metal spindle in an electric arc smelting furnace, adopting a rapid cooling technology, reheating the metal spindle to a molten state in a quartz tube during melt spinning, and spraying the metal spindle onto a rapidly rotating copper wheel under the action of air pressure difference to obtain a strip.

10. The method of claim 9, wherein the Ti, Zr, Be, Co, Y starting materials have a purity of greater than 99.95%.

11. The method of claim 9, wherein the vacuum of the arc melting is 10 degrees^-3Above MPa, and smelting for at least 3-4 times to ensure uniform structure and no segregation.

12. The method of claim 9, wherein the melt spinning is by induction heating.

13. The method as claimed in claim 9, wherein the slit of the quartz tube has a length of 10mm and a width of 0.5mm, the melt spinning is performed by induction heating, the induced current is 17-22A, and the air pressure difference is not less than 0.05 MPa.

14. The method of claim 9, wherein the rapid cooling technique employs process parameters as follows: the protective gas is argon; controlling the gas pressure at 0.5-0.8 MPa; the spraying distance is controlled to be 2-3 mm.