Belt-shaped brazing material for medium and low temperature brazing of titanium alloy, and preparation method and brazing method thereof

Abstract

The invention provides a belt-shaped brazing material for medium and low temperature brazing of titanium alloy, and a preparation method and a brazing method thereof. The belt-shaped brazing materialfor the medium and low temperature brazing of the titanium alloy consists of Ti element, Zr element, Cu element and Ni element, wherein all the element compositions are compounded by following weightpercentage: Ti greater than or equal to 51.0% and less than or equal to 60.0%, Zr greater than or equal to 15.0% and less than or equal to 19.0%, Cu greater than or equal to 12.0% and less than or equal to 14.0%, Ni greater than or equal to 13.0% and less than or equal to 16.0%, and Cu+Ni greater than or equal to 25.0% and less than or equal to 30.0%. By improving a Ti-Zr-Cu-Ni brazing material, optimizing the content of the Zr element, and controlling the total content of the Cu element and the Ni element, the belt-shaped brazing material for the medium and low temperature brazing of the titanium alloy realizes the purpose of reducing the melting point to a range from 830 DEG C to 880 DEG C, improves diffusivity of the brazing material so as to reduce the quantity of interfacial compounds, realizes that the level of tensile strength of a Ti2AlNb-TC4 dissimilar brazed joint reaches 905MPa, and the level of tensile strength of a TA2 brazed joint reaches 463MPa, meanwhile facilitates forming of a brazing material foil belt, reduces cost of the brazing material, and improves applicability of the brazing material.

Description

technical field [0001] The invention relates to brazing technology, in particular to a strip-shaped brazing material for medium and low temperature brazing of titanium alloys, a preparation method and a brazing method. Background technique [0002] Titanium thin-walled components have the characteristics of light weight. For example, titanium alloy radiators and honeycomb sandwich structures manufactured by brazing technology have been used in the aerospace field. Intermetallic compounds form at the weld interface of the structure. Compared with the phase transition point (960℃~980℃) of commonly used titanium alloy TC4 and TC1 titanium alloy materials, when using pure titanium materials, such as industrial pure titanium (TA1, TA2) phase transition point is 882℃-885℃, The phase transition point of the SP700 (Ti-4.5Al-3.0V-2.0Mo-2.0Fe, weight percent) titanium alloy suitable for the manufacture of a wide version is about 885°C-890°C. The thin-walled structure of this type of ...

AI Technical Summary

Problems solved by technology

According to the melting point of the brazing filler metal, the commonly used brazing filler metals for titanium materials and Ti-Al alloys can be divided into the following categories. Ag-Cu-Ti solder) and some zirconium-based solder (Zr-Ti-Ni-Cu, Zr content is 50-70%, weight percentage), but due to the large difference between the constituent elements of the solder and the matrix elements , lead to complex interface structure, and solder containing a large amount of Ag element (content above 30%) will reduce the corrosion resistance of joints

[0005] The second type is medium-temperature brazing filler metal, and its operating temperature range is 870°C-930°C. For example, Ti-37.5Zr-15Cu-15Ni (weight percent) brazing filler metal, which is common in titanium-based brazing filler metals, reports that its operating temperature can be 875°C. , 930°C and other temperatures, it can be used for brazing titanium materials and Ti-Al alloys, but the corresponding brazing interface is very easy to form intermetallic compounds, such as TiNi3

[0006] The third type is Ti-Zr-Cu-Ni-X (X=Fe, Be, Co, Fe, Al, Si, etc.) high-temperature solder, with a melting point in the range of 940°C-1000°C, including Ti-15Cu-15Ni (weight percent) solder, its liquidus temperature range is about 900°C, and its operating temperature range is 950°C-1000°C, which is higher than the phase transition point of most titanium alloys, so Ti-Zr-Cu-Ni-X has a high temperature Brazing filler metal and Ti-15Cu-15Ni filler metal are not suitable for brazing titanium alloys, especially pure titanium materials

[0013] 2) When the structure to be welded is a thin-walled structure, the diffusion ability of the solder needs to be improved

Due to the increase of the sum of Cu and Ni elements in the brazing filler metal, the brazing filler metal is not easy to diffuse into the matrix during the brazing process, resulting in erosion and reduced joint strength, which is especially obvious for brazing of thin-walled structures

[0014] 3) When the material to be welded contains Ti-Al alloy, the problem of complex interface structure needs to be solved urgently

[0015] 4) Preparation of foil strip solder

Therefore, solders with such composition cannot be prepared as foil strips by rapid solidification method.

[0017] At present, there are few varieties of medium and low temperature solders that can braze titanium materials containing pure titanium, and / or Ti-Al alloys, and / or combinations of titanium materials and Ti-Al alloy materials

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