Multilayer sandwich brazing filler metal foil for titanium alloy brazing and preparation method thereof
Technical Field
The invention belongs to the technical field of brazing materials, and particularly relates to a multilayer sandwich brazing filler metal foil for titanium alloy brazing and a preparation method thereof.
Background
Titanium and titanium alloy have light in weight, high strength, high temperature performance and low temperature performance, excellent corrosion resistance and other characteristics, and are widely applied to the industrial fields of aviation, aerospace, shipbuilding, metallurgy, chemical industry, petroleum and the like.
In order to obtain a soldered joint having high strength and good corrosion resistance and heat resistance, a Ti — Zr-based solder is currently used as a solder material for titanium alloys. However, since the melting point of the Ti-Zr based solder is high, Ni and Cu are commonly used as melting point reducing elements in the Ti-Zr based solder. The Ni and Cu elements have strong combination with Ti in the titanium alloy base material, so that a large amount of brittle compounds are easily generated, and the titanium alloy joint is brittle.
In addition, although the Ti-Zr-based brazing filler metal in the prior art is added with melting-reducing elements such as Ti-37.5Zr-15Cu-15Ni brazing filler metal (805-815 ℃), the melting temperature is still high, and when the titanium alloy is brazed, the grains of the base material of the titanium alloy are easily coarsened due to long-time heating, so that the performance of a joint is influenced.
Disclosure of Invention
The invention aims to provide a multilayer sandwich brazing filler metal foil for titanium alloy brazing, which can improve the brittleness of joints and reduce brazing temperature.
The second purpose of the invention is to provide a preparation method of the multilayer sandwich brazing filler metal foil for titanium alloy brazing.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a multilayer sandwich brazing filler metal foil for titanium alloy brazing comprises a titanium-based amorphous brazing filler metal core layer and fusion-reducing bonding layers compounded on two side faces of the titanium-based amorphous brazing filler metal core layer; a barrier layer is compounded on the melting-reducing bonding layer; the component of the melting-down bonding layer is In52Sn 48; the barrier layer comprises one or any combination of Nb, Mo and Ta.
The multilayer sandwich brazing filler metal foil for titanium alloy brazing contains the blocking layer, and Nb, Mo and Ta elements have the advantages of high melting point, good atom activation energy and infinite mutual solubility with Ti, can form a solid solution with Ti, and can effectively block Ti from carrying out violent chemical combination reaction with Cu and Ni elements in a brazing filler metal layer to form a brittle phase when being compounded with Ti alloy, so that the toughness of a joint is improved.
The solder foil provided by the invention takes In52Sn48 with a melting point of 118 ℃ as a melting-reduction bonding layer, has good fluidity and wettability, has good hot dipping property, can be used for metallurgically compounding the solder foil and barrier metal, is low-melting elements In and Sn, can be subjected to chemical combination reaction with Ti, Cu and Ni, can be diffused into a brazing seam In the brazing process, reduces the brazing temperature, and further improves the joint performance; in addition, tin can fix titanium element, and avoid titanium and other elements from forming brittle phase.
Further, the titanium-based amorphous solder core layer comprises the following components in parts by mass: 32-38 parts of Ti, 32-38 parts of Zr, 12-18 parts of Cu and 12-18 parts of Ni.
Further, the titanium-based amorphous solder core layer is prepared by adopting a method comprising the following steps: and smelting and melt-spinning the components for forming the brazing filler metal. Further, the smelting is carried out in a non-consumable vacuum smelting furnace. The melt spinning is carried out in a vacuum melting melt spinning machine.
Further, the thickness of the melting-reducing bonding layer is 6-10 mu m.
Further, the thickness of the barrier layer is 5-8 μm.
Further, the thickness of the titanium-based amorphous solder core layer is 25-30 mu m. The thickness of the titanium-based amorphous brazing filler metal core layer, the thickness of the barrier layer and the thickness of the melting-reducing bonding layer are controlled to regulate and control the mass ratio of the three layers, so that the components of the in-situ combined brazing filler metal are in a proper range.
The preparation method of the multilayer sandwich brazing filler metal foil for titanium alloy brazing adopts the technical scheme that:
a preparation method of a multilayer sandwich brazing filler metal foil for titanium alloy brazing comprises the following steps: and superposing the melting-reducing bonding layer and the blocking layer on the two side surfaces of the titanium-based amorphous solder core layer in sequence, and then heating, pressurizing and compounding.
According to the preparation method of the multilayer sandwich brazing filler metal foil for titanium alloy brazing, the melting-reducing bonding layer is utilized to compound the barrier layer on the titanium-based amorphous brazing filler metal core layer, and the barrier layer can prevent copper and nickel elements in the brazing filler metal and the titanium alloy from generating brittle phases during brazing, so that the reduction of the performance of a joint is avoided; the preparation method of the invention has simple process and is suitable for industrial large-scale production.
Further, the stacking comprises the steps of: carrying out hot dip coating on the titanium-based amorphous solder core layer In the In52Sn48 molten solution, and forming fusion reduction bonding layers on two side surfaces of the titanium-based amorphous solder core layer; the method comprises the steps of coating In52Sn48 molten liquid on the compounded surface of a barrier layer and a titanium-based amorphous solder core layer to form the barrier layer with a melting-reducing bonding layer on one side, and then stacking the barrier layer and the titanium-based amorphous solder core layer with the melting-reducing bonding layer. Still further, the coating is brushing. When stacking, the blocking layer is provided with one side of the melting-reducing bonding layer and is attached to the titanium-based amorphous brazing filler metal core layer with the melting-reducing bonding layer on the two sides.
Further, before the In52Sn48 molten solution is hot-dipped on both sides of the titanium-based amorphous solder core layer, the titanium-based amorphous solder core layer is heated. Further, heating the titanium-based amorphous solder core layer to 110-120 ℃.
Further, before the surface of the barrier layer compounded with the titanium-based amorphous solder core layer is coated with In52Sn48 molten liquid, the barrier layer is heated. Further, the barrier layer is heated to 110-120 ℃.
Further, In order to uniformly coat the In52Sn48 melt on two side surfaces of the titanium-based amorphous solder, the hot dip coating is to pass the titanium-based amorphous solder core layer through the In52Sn48 melt. The speed of the titanium-based amorphous solder core layer passing through the In52Sn48 melt is 30-50 mm/s. The thickness of the melting-reducing bonding layers formed on the two side faces of the titanium-based amorphous solder core layer is 3-5 microns. The thickness of the melting-down bonding layer formed on the surface, compounded with the titanium-based amorphous solder core layer, of the blocking layer is 3-5 microns.
Further, the In52Sn48 melt is prepared by a method comprising the following steps: the In52Sn48 was heated and melted to form an In52Sn48 melt. Further, heating the In52Sn48 to 110-120 ℃. Further, the heating of In52Sn48 was performed In a tin plating bath. The titanium-based amorphous solder core layer passes through the In52Sn48 molten liquid In the tin plating bath.
Further, in order to enable the blocking layer, the melting-reducing bonding layer and the titanium-based amorphous core layer to be more fully compounded, the melting-reducing bonding layer and the blocking layer are sequentially superposed on two side faces of the titanium-based amorphous brazing filler metal core layer, the heating temperature is 110-120 ℃, the pressurizing pressure is 0.3-3 MPa, and the pressurizing time is 20-30 min.
Further, the preparation method of the barrier layer comprises the following steps: and (3) melting, extruding and rolling and forming one or any combination of metals of Nb, Mo and Ta.
Drawings
FIG. 1 is a schematic structural diagram of a multilayer sandwich brazing filler metal foil for brazing titanium alloy In example 1 of the present invention, where 1 is an Nb layer, 2 is an In52Sn48 layer, and 3 is a Ti-36.3Zr-13.6Cu-13.6Ni core layer;
fig. 2 is a schematic diagram of a manufacturing process route of a multilayer sandwich brazing filler metal foil for titanium alloy brazing In example 7 of the present invention, where 1 is an Nb layer, 2 is a first In52Sn48 layer, 3 is a second In52Sn48 layer, 4 is a tunnel furnace, 5 is a Ti-36.3Zr-13.6Cu-13.6Ni core layer, 6 is a tin plating bath, and 7 is a winder;
FIG. 3 is an interface topography of a brazing seam after Ti-37.5Zr-15Cu-15Ni conventional brazing filler metal is used for brazing TC4 alloy;
FIG. 4 is an interface topography of a braze joint after multi-layer sandwich brazing filler metal foil for titanium alloy brazing TC4 alloy in example 1 is brazed;
FIG. 5 is a graph showing an energy spectrum analysis of A, B points in a brazing seam after conventional brazing alloys of Ti-37.5Zr-15Cu-15 Ni.
Detailed Description
The present invention will be further described with reference to the following examples.
First, embodiment of multilayer sandwich brazing filler metal foil for titanium alloy brazing
Example 1
The multilayer sandwich brazing filler metal foil for titanium alloy brazing in the embodiment is in a five-layer sandwich shape, as shown in fig. 1, two surface layers are barrier layers 1, two outer layers are melting-reducing bonding layers 2, and a core layer is a titanium-based amorphous brazing filler metal core layer 3, wherein the barrier layers are Nb and the thickness is 5 μm; the melting-down bonding layer is In52Sn48 and has the thickness of 6 mu m; the titanium-based amorphous solder core layer (Ti-36.3Zr-13.6Cu-13.6Ni) comprises the following components in parts by mass: 32.0 parts of Ti, 32.0 parts of Zr, 12.0 parts of Cu and 12.0 parts of Ni, and the thickness is 25 mu m.
Example 2
The multilayer sandwich brazing filler metal foil for titanium alloy brazing in the embodiment is in a five-layer sandwich shape, two surface layers are barrier layers, two outer layers are fusion-reducing bonding layers, and a core layer is a titanium-based brazing filler metal core layer, wherein the barrier layers are Mo and the thickness is 6 mu m; the melting-down bonding layer is In52Sn48 and has the thickness of 8 mu m; the titanium-based amorphous solder core layer (Ti-36.1Zr-13.8Cu-13.8Ni) comprises the following components in parts by mass: 34.0 parts of Ti, 34.0 parts of Zr, 13.0 parts of Cu and 13.0 parts of Ni, and the thickness is 28 mu m.
Example 3
The multilayer sandwich brazing filler metal foil for titanium alloy brazing in the embodiment is in a five-layer sandwich shape, two surface layers are barrier layers, two outer layers are melting-reducing bonding layers, and a core layer is a titanium-based brazing filler metal core layer, wherein the barrier layer is Ta and the thickness is 8 mu m; the melting-down bonding layer is In52Sn48 and has the thickness of 10 mu m; the titanium-based amorphous solder core layer (Ti-35Zr-15Cu-15Ni) comprises the following components in parts by mass: 35.0 parts of Ti, 35.0 parts of Zr, 15.0 parts of Cu and 15.0 parts of Ni, and the thickness is 30 mu m.
Example 4
The multilayer sandwich brazing filler metal foil for titanium alloy brazing in the embodiment is in a five-layer sandwich shape, two surface layers are barrier layers, two outer layers are fusion-reducing bonding layers, and the core layer is a titanium-based brazing filler metal core layer, wherein the barrier layers are composed of Nb and Mo in a mass ratio of 1:1 and have a thickness of 6 microns; the melting-down bonding layer is In52Sn48 and has the thickness of 6 mu m; the titanium-based amorphous solder core layer (Ti-34.6Zr-15.4Cu-15.4Ni) comprises the following components in parts by mass: 36.0 parts of Ti, 36.0 parts of Zr, 16.0 parts of Cu and 16.0 parts of Ni, and the thickness is 25 mu m.
Example 5
The multilayer sandwich brazing filler metal foil for titanium alloy brazing in the embodiment is in a five-layer sandwich shape, two surface layers are barrier layers, two outer layers are fusion-reducing bonding layers, and the core layer is a titanium-based brazing filler metal core layer, wherein the barrier layers are composed of Nb, Mo and Ta in a mass ratio of 1:1:1, and the thickness of the barrier layers is 8 micrometers; the melting-down bonding layer is In52Sn48 and has the thickness of 10 mu m; the titanium-based amorphous brazing filler metal core layer (Ti-33.9Zr-16.1Cu-16.1Ni) comprises the following components in parts by mass: 38.0 parts of Ti, 38.0 parts of Zr, 18.0 parts of Cu and 18.0 parts of Ni, and the thickness is 30 mu m.
Second, example of preparation method of multilayer sandwich brazing filler metal foil for titanium alloy brazing
Example 6
The embodiment is a preparation method of the multilayer sandwich solder foil for titanium alloy brazing in the embodiment 1, and the preparation method comprises the following steps:
1) weighing the components according to the stoichiometric ratio of the titanium-based amorphous solder, and smelting the components through a non-consumable vacuum smelting furnace and a vacuum melting and tape throwing machine to prepare a 25-micron Ti-36.3Zr-13.6Cu-13.6Ni solder core layer;
2) melting, extruding and rolling Nb metal into Nb metal foil with the diameter of 5 mu m;
3) putting the In52Sn48 into a tin plating bath, heating to 120 ℃, and melting into In52Sn48 molten solution;
4) heating the Nb metal foils prepared In the two steps 2) to 110 ℃ through a tunnel furnace, uniformly brushing an In52Sn48 molten solution on the surface of the two Nb metal foils compounded with the titanium-based amorphous solder, and forming an Nb layer with a first In52Sn48 layer of which one side is 3 microns;
5) heating the Ti-36.3Zr-13.6Cu-13.6Ni solder core layer obtained In the step 1) to 110 ℃ through a tunnel furnace, and then passing through a tinning bath containing In52Sn48 melt In the step 3) at the speed of 50mm/s to form second In52Sn48 layers of 3 mu m on two side surfaces of the Ti-36.3Zr-13.6Cu-13.6Ni solder core layer;
in other implementation cases, on the basis of the embodiment, the Ti-36.3Zr-13.6Cu-13.6Ni solder core layer coming out of the tunnel furnace passes through the tinning bath containing the In52Sn48 melt In the step 3) at the speed of 30mm/s or 40mm/s, and a second In52Sn48 layer with the thickness of 3-5 microns is formed on two side surfaces of the Ti-36.3Zr-13.6Cu-13.6Ni solder core layer;
6) heating the two Nb layers compounded with the first In52Sn48 layer obtained In the step 4) and the Ti-36.3Zr-13.6Cu-13.6Ni brazing filler metal core layer with the second In52Sn48 layer on two side surfaces obtained In the step 5) to 110 ℃ through a tunnel furnace, simultaneously pressurizing for 1.5MPa for compounding, and maintaining the pressure for 20min according to the sequence of the Nb layer, the first In52Sn48 layer, the second In52Sn48 layer, the Ti-36.3Zr-13.6Cu-13.6Ni brazing filler metal core layer, the second In52Sn48 layer, the first In52Sn48 layer and the Nb layer from top to bottom.
On the basis of the embodiment, the tunnel furnace in the step 5) is heated to 110 ℃ or 115 ℃, and is simultaneously pressurized to 0.3MPa, 1MPa, 2MPa or 3MPa for compounding, and the pressure is maintained for 25min or 30min, so that the multilayer sandwich brazing filler metal foil for titanium alloy brazing similar to the embodiment can be obtained.
As shown In FIG. 2, In the process of preparing the multilayer sandwich solder foil for titanium alloy brazing, a Ti-36.3Zr-13.6Cu-13.6Ni solder core layer 5 discharged from a tunnel furnace 4 is passed through a tinning bath 6 containing an In52Sn48 melt to form second In52Sn48 layers 3 on both sides of the Ti-36.3Zr-13.6Cu-13.6Ni solder core layer 5, an In52Sn48 melt In the tinning bath 6 is uniformly brushed on the surface where two Nb metal foils and a titanium-based amorphous solder are compounded to form an Nb layer 1 with a first In52Sn48 layer 2 on one side, and the Nb layer 1, the first In52Sn48 layer 2, the second In52Sn48 layer 3, the Ti-36.3Zr-13.6Cu-13.6Ni 5, the second In52Sn48 layer, the first In52Sn48 layer 2, the second In52Sn48 layer, the first In52Sn 352 layer and the Nb layer are sequentially laminated from top to the middle of the sandwich solder foil, and fastening the pressing plates at the two sides through screws, entering the tunnel furnace 4, heating and pressurizing, removing the pressing plates after the pressing plates are discharged out of the tunnel furnace, and finally winding the pressing plates by using a winding machine 7 to obtain the multilayer sandwich brazing filler metal foil for titanium alloy brazing.
By referring to the method of example 7, the multi-layer sandwich solder foil products of examples 2-5 can be prepared accordingly.
Third, Experimental example
Experimental example 1 characterization of the morphology of the joints
The multilayer sandwich brazing filler metal foil for titanium alloy brazing and the conventional Ti-37.5Zr-15Cu-15Ni brazing filler metal in the embodiment 1 are respectively used for vacuum brazing of TC4 alloy plates with the width of 20mm, the length of 60mm and the thickness of 3mm, wherein the brazing process parameter of the multilayer sandwich brazing filler metal foil is 850 ℃/10min, the brazing process parameter of the conventional brazing filler metal foil is 900 ℃/10min, and the joint form is lap joint. After welding, sampling to prepare a metal joint, and observing and analyzing the interface morphology of TC4 joints brazed by two solders by using a scanning electron microscope, as shown in FIGS. 3 and 4.
It can be seen from fig. 3 and 4 that, the Ti-37.5Zr-15Cu-15Ni conventional brazing filler metal brazing TC4 alloy interface has obvious gray brittle layer strips (dotted line positions) on two side edges, while the brazing filler metal brazing TC4 alloy interface in the embodiment 1 has no obvious brittle layer strips, the brazing filler metal is needle-shaped, mutually penetrates in the matrix on two sides of the brazing seam, the diffusion between the brazing filler metal and the titanium alloy base metal is sufficient, and the brazing seam structure distribution is relatively uniform.
Experimental example 2 EDS analysis of joints
EDS spectrum analysis was performed on the conventional Ti-37.5Zr-15Cu-15Ni solder of Experimental example 1, and the results are shown in FIG. 5 and Table 1.
TABLE 1 EDS analysis results of points A and B in FIG. 4
As can be seen from FIG. 5 and Table 1, the A-site gray black phase has high contents of Cu and Ni elements and forms various brittle compounds with Ti, such asTiCu、Ti2Cu、Ti3Ni2And the B-point white phase is a Ti-based solid solution.
Experimental example 3 test of mechanical Properties of Joint
This experimental example compares the mechanical properties of the joints of TC4 alloy vacuum brazed by the brazing filler metal of example 1 and the conventional brazing filler metal of Ti-37.5Zr-15Cu-15Ni, wherein the shear strength test of the joints is performed according to GB/T11363-.
TABLE 2 mechanical properties of soldered TC4 alloy joints made with different solders
As can be seen from Table 2, the TC4 alloy joint brazed by the conventional Ti-37.5Zr-15Cu-15Ni solder has poor toughness and slightly low strength, while the TC4 alloy joint brazed by the solder in the embodiment of the invention has high impact toughness value and good joint toughness.