JPH0338948B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] This invention relates to a method for manufacturing a composite brazed member that is lightweight, has a high cooling effect, and is suitable for use as, for example, a reflector for a carbon dioxide laser or an inner wall material for a vacuum furnace. It is. [Prior Art] Conventionally, as reflectors for carbon dioxide gas, for example, mirrors made of pure Cu with a mirror finish, and mirrors made of pure Cu with an Au plating on the mirror surface have been known. There is. However, with these pure Cu reflectors,
As the laser irradiation time increases, metal and non-metal vapor generated from the processed material adheres to the surface, which not only reduces its reflectance, but also causes the surface to absorb the laser energy, melt, and reflect. Accidents such as damaging mirrors have occurred. To prevent such accidents, it is necessary to periodically remove deposits from the surface, but the pure Cu and Al plating that makes up the reflector is very soft, so when wiping it off, it is necessary to remove the deposits from the surface. It is easy to damage the mating surface, and as a result, the reflective properties are impaired. For this reason, in recent years, hard pure copper has been used as a material for carbon dioxide laser reflectors, replacing pure Cu.
The use of Mo is becoming established. This purity
Mo reflecting mirrors, especially single crystal ones and polycrystal ones with fine crystal grains, are easy to polish to provide a surface with uniform reflectance, and have excellent performance with less adhesion of evaporated matter. It is something that demonstrates the. [Problems to be solved by the invention] On the other hand, since carbon dioxide laser devices are installed not only in ground equipment but also in space stations, there is a growing demand for the device itself to be lightweight. Along with this, there is a strong desire to reduce the weight of reflective mirrors made of pure Mo or pure W, which have a high specific gravity (heavy). [Means for Solving the Problems] Therefore, from the above-mentioned viewpoint, the present inventors have developed a material made of pure Mo that constitutes the reflecting mirror of the carbon dioxide laser, the inner wall material of the vacuum furnace, and the like. As a result of focusing on various parts made of heavy Mo alloy, pure W, or W alloy, and conducting research to reduce their weight, we found that pure Mo, Mo alloy,
A part of a heavy member made of either pure W or W alloy is replaced with lightweight (low specific gravity) pure W.
If it is made of lightweight Al or Al alloy material, the weight will be reduced accordingly, but for example, the specific gravity of pure Mo and pure W is 10.2 g/cm ³ and 19.3 g/cm ³ , while pure The specific gravity of Al is 2.7g/ ^cm3 ,
Also, the thermal expansion coefficient of pure Mo and pure W is 5×10 ^-6 /℃
These heavy materials and lightweight materials have different properties in various respects, such as 4.3×10 ^-6 /℃ and 23.3×10 ^-6 /℃ for pure Al. Due to this, it is difficult to braze these two parts with high joint strength, and it is impossible to reduce the weight by applying ion plating to each of the brazing surfaces of these two parts. When a Cu layer with an average layer thickness of 0.01 to 50 μm is firmly formed using the method, and vacuum brazing is performed using an Al alloy brazing material containing 6 to 14% Si, both parts become strong. They obtained the knowledge that a composite brazed member that is brazed with high joint strength can be obtained. This invention was made based on the above knowledge, and it is based on pure Mo, Mo alloy, pure W, and W.
An average layer thickness of 0.01 to 50 μm is applied by ion plating to the brazing surface of a heavy component made of any of the alloys and the brazing surface of a light component made of pure Al or Al alloy. of
The Cu layer is fixedly formed, and then these two members are bonded together.
This method is characterized by a method for manufacturing a composite brazing member in which vacuum brazing is performed using an Al alloy brazing filler metal containing 6 to 14% by weight of Si. In the method of this invention, the average layer thickness of the Cu layer is limited to 0.01 to 50 μm because if the average layer thickness is less than 0.01 μm, the wettability with the brazing material will be insufficient and the desired strong bonding strength will not be achieved. On the other hand, if the average layer thickness exceeds 50μm, internal strain will remain during the formation of the Cu layer, and peeling will occur in the Cu layer during brazing. be. Also, the same brazing filler metal Si
Regarding the content, if the content is less than 6% by weight, the melting point of the brazing filler metal will exceed 660℃, which will be too high.
There are cases where brazing temperatures higher than the melting point of light parts are required, making brazing impossible, and on the other hand, when the content exceeds 14% by weight, the brazed part becomes brittle. Therefore, the content was determined to be 6 to 14% by weight. Furthermore, on the surfaces of both of the above components, especially the light components, there is an oxide film that reduces the wettability of the brazing filler metal, but according to the ison plating method, this oxide film is removed while the Cu layer is removed. Formation of a Cu layer using the ion plating method is essential, as it significantly improves the wettability of the brazing filler metal, especially when brazing involves face-to-face bonding. This increases the necessity. [Example] Next, the method of the present invention will be specifically explained with reference to Examples. As heavy members, various members having the compositions shown in Table 1 and having dimensions of diameter: 100 mm x thickness: 1 mm were prepared, and as light members, the compositions also shown in Table 1 were prepared. Prepare various parts with dimensions of 100 mm in diameter x 20 mm in thickness, then use an ion plating device on one side of these parts to be brazed,
After ion cleaning under normal conditions, a Cu layer of the average layer thickness also shown in Table 1 is fixedly formed, followed by a solder with a thickness of 0.3 mm having the composition also shown in Table 1. The material is sandwiched between the brazing surfaces of both parts, stacked on top of each other with the heavy part facing down, a 3 kg weight is placed on top of this, and vacuum brazing is performed under normal conditions. Invention methods 1 to 5 were each carried out. Next, the shear strength of the joint surfaces of the composite brazed members obtained by methods 1 to 5 of the present invention was measured using a universal testing machine, and the joint strength was evaluated. The measurement results are shown in Table 1.

〔Effect of the invention〕

From the results shown in Table 1, it can be seen that in the composite brazed parts manufactured by methods 1 to 5 of the present invention, pure Mo, Mo alloy, pure W, which were conventionally considered to be extremely difficult to join by brazing, and a heavy member made of either W alloy and pure Al.
It is also clear that the light member made of Al alloy is brazed with strong bonding strength. As mentioned above, according to the method of this invention, pure
Heavy members made of Mo, Mo alloy, pure W, and W alloy, and pure Al or Al
Since it is possible to braze a light member made of an alloy with a strong joint strength, it is possible to replace a part of the heavy member with the light member, which makes it possible to create a composite brazed member that is lighter in weight. In addition, the light materials have an excellent cooling effect, so they can maintain excellent performance over a long period of time when used in the manufacture of reflectors for carbon dioxide lasers, inner wall materials for vacuum furnaces, etc. Industrially useful effects are brought about, such as being exhibited over a long period of time.

Claims (1)

[Claims] 1. A brazing surface of a heavy member made of pure Mo, a Mo alloy, pure W, or a W alloy, and a brazing surface of a light member made of pure Al or an Al alloy. A Cu layer with an average layer thickness of 0.01 to 50 μm is fixedly formed on each of the mounting surfaces by the ion plating method, and then both these parts are bonded to a brazing filler metal made of an Al alloy containing 6 to 14% by weight of Si. A method for manufacturing a composite brazing member, characterized by performing vacuum brazing using.