CN104690386A - Method for connecting Cf/LAS composite material via AgCuTi brazing filler metal - Google Patents

Abstract

The invention discloses a method for connecting C _f /LAS composite materials with AgCuTi solder, which is characterized in that the steps are as follows: step 1, machining the C _f /LAS composite materials, step 2, processing the C f /LAS composite materials obtained in step 1 to be connected The connection surface of the C _f /LAS composite material is treated, and then the connection surface of the C _f /LAS composite material is put into an acetone solution for ultrasonic cleaning; Step 3, the AgCuTi solder is placed on the C _f /LAS composite material to be connected Between the connecting surfaces, assemble into an assembly of C _f /LAS composite material/AgCuTi solder/C _f/ LAS composite material stacked in sequence, step 4, place the assembly obtained in step 3 in a vacuum heating furnace, vacuumize, It can be heated by electricity and then cooled. This invention is mainly used to connect small-sized or simple-shaped C _f /LAS composite parts to obtain larger-sized or complex-shaped components, which can improve the creep resistance of high-temperature structures Deformation performance and thermal shock resistance, has great application prospects.

Description

A method of joining Cf/LAS composite materials with AgCuTi solder

technical field

The invention relates to a method for connecting composite materials, in particular to a method for connecting C _f /LAS composite materials with AgCuTi solder.

Background technique

We know that C _f /LAS is a continuous carbon fiber reinforced lithium aluminum silicate glass ceramic matrix composite material. As a new type of composite material, it has many excellent properties, including high strength, high stiffness, excellent toughness, Low density and good wear resistance have become a very advantageous composite material. At the same time, the axial thermal expansion coefficient of carbon fibers in C _f /LAS composites is almost zero, or even negative thermal expansion, so C _f /LAS composites have excellent thermomechanical properties such as good thermal shock resistance and thermal shock resistance. It is used in high-temperature heat exchangers, high-temperature windows, radar radomes, various precision equipment and instruments and is expected to become a new generation of laser materials.

Although C _f /LAS composites have many advantages that other engineering materials can't match, their weakness of high brittleness and impact resistance seriously hinders its use as a high-performance material. When C _f /LAS composite components with large size or complex shape are required, it is necessary to connect C _f /LAS composite materials with small size or simple shape by means of connection.

In view of the comprehensive excellent performance of C _f /LAS composite materials, connecting C _f /LAS composite materials together to prepare composite components can give full play to their performance advantages, especially in the fields of high-temperature structural parts manufacturing and other fields. application prospects. However, mechanical joining methods such as riveting have a heavy negative mass, so brazing is an ideal method for joining _Cf /LAS composites. So far, there are no literature reports on Cf _/ LAS composite junctions.

Contents of the invention

The invention aims to solve the connection problem of C _f /LAS composite materials, and provides a method for connecting C _f /LAS composite materials by using AgCuTi solder.

The present invention can reach by following measures.

A method adopting AgCuTi solder to connect _Cf /LAS composite material is characterized in that the steps are as follows:

Step 1. Machining the C _f /LAS composite material to obtain the C _f /LAS composite material to be connected;

Step 2: Polish the connection surface of the C _f /LAS composite material to be connected obtained in step 1 with sandpaper, and then put the connection surface of the C _f /LAS composite material into an acetone solution for ultrasonic cleaning for 5 minutes to 10 minutes;

Step 3, placing the AgCuTi solder between the connecting surfaces of the C _f /LAS composite materials to be connected, and assembling into an assembly in which the C _f /LAS composite material/AgCuTi solder/C _f/ LAS composite material are stacked in sequence, wherein The thickness of the AgCuTi solder foil is 25um~200um, and the Ti content is 1%~10%;

Step 4. Place the assembly obtained in Step 3 in a vacuum heating furnace, and then evacuate it. When the vacuum degree reaches (1.3~2.0)×10 ^-3 Pa, turn on the electric heating again, and control the heating rate to 10°C/min~30 ℃/min, heat up to 860~940℃, then keep it warm for no more than 30min, then cool down, control the cooling rate at 3℃/min~10℃/min, cool down to 300℃ and then cool with the furnace, that is, the use of AgCuTi solder is completed Methods for joining _Cf /LAS composites.

The mechanical processing described in step 1 of the present invention refers to the processing by a slicer cutting machine, such as a semi-automatic internal circle slicer, a fully automatic sheet material cutting machine, and the like.

Step 2 of the present invention adopts the sandpaper used for grinding the connecting surface with sandpaper to be 600# to 1000#.

The concentration of the acetone solution described in the second step of the present invention is ≥99.5%.

The ultrasonic cleaning described in the second step of the present invention is to use a Jiekang brand digital ultrasonic cleaning machine (SP-08A) for ultrasonic cleaning.

The thickness of the AgCuTi solder foil described in the third step of the present invention is 50um-150um, and the Ti content is 3%-7%.

The thickness of the AgCuTi solder foil described in the third step of the present invention is 100um, and the Ti content is 4.5%.

In step 4 of the present invention, the vacuum degree of the vacuum heating furnace reaches 1.5×10 ^-3 Pa, the temperature rise rate is controlled to 20°C/min, the temperature rises to 900°C, the holding time is 10 minutes, and the cooling rate is 5°C/min.

The invention can realize the joint connection of C _f /LAS composite material. First, Ti reacts with O, Al and Si in the C _f /LAS composite material to form a compound to realize metallurgical connection; secondly, Ti and carbon fiber generate TiC , which improves the mechanical properties of the joint to a certain extent. By controlling the brazing temperature (860~940°C) and holding time (0~30min), the thickness of the reaction layer and the distribution of the reaction phase in the joint can be controlled, and then the brazing temperature can be controlled. The microstructure and performance of the welded joint successfully realized the connection of C _f /LAS composite materials, and the obtained joint was complete and compact without cracks and other defects. After testing, the average shear strength of the joint at room temperature reached 8.4MPa. The main application of the present invention It is used to connect small-sized or simple-shaped C _f /LAS composite parts to obtain larger-sized or complex-shaped components, which can effectively improve the creep resistance and thermal shock resistance of existing parts, and has extremely Great application prospects.

Description of drawings

Fig. 1 is a backscattered electron photo of the joint interface structure of the C _f /LAS composite material of the present invention.

Detailed ways

The present invention will be further described below:

A method for connecting C _f /LAS composite materials using AgCuTi solder, characterized in that the steps are as follows: step 1, machining the C _f /LAS composite materials to obtain the C _f /LAS composite materials to be connected, the described Mechanical processing refers to the processing of slicer cutting machines, such as semi-automatic internal circle slicer, automatic sheet cutting machine, etc. Step 2, the connection surface of the C _f /LAS composite material to be connected obtained in step 1 is polished with sandpaper and then polished , and then put the connecting surface of the C _f /LAS composite material into an acetone solution for ultrasonic cleaning for 5 minutes to 10 minutes, and use sandpaper to polish the sandpaper used for grinding step by step with 600# to 1000# water sandpaper, and the concentration of the acetone solution is ≥ 99.5%, ultrasonic cleaning is performed by using Jiekang brand digital ultrasonic cleaning machine (SP-08A); step 3, placing AgCuTi solder between the connecting surfaces of the C _f /LAS composite materials to be connected, and assembling C _f /LAS composite material/AgCuTi solder/C _f/ LAS composite material stacked in sequence, wherein the thickness of the AgCuTi solder foil is 25um~200um, and the Ti content is 1%~10%; the AgCuTi solder foil is preferred The thickness is 100um, and the Ti content is 4.5%; step 4, place the assembly obtained in step 3 in a vacuum heating furnace, vacuumize, and when the vacuum degree reaches (1.3~2.0)×10 ^-3 Pa, turn on the electric heating again, Control the heating rate at 10°C/min~30°C/min, raise the temperature to 860~940°C, then keep it warm for no more than 30 minutes, then cool down, control the cooling rate at 3°C/min~10°C/min, cool to 300°C before Cooling with the furnace, that is, the method of using AgCuTi solder to join the C _f /LAS composite material is completed. In step 4, the vacuum degree of the vacuum heating furnace is preferably 1.5×10 ^-3 Pa, and the heating rate is controlled at 20°C/min, and the temperature is raised to 900°C , the holding time is 10min, and the cooling rate is 5°C/min.

The invention can realize the joint connection of C _f /LAS composite material. First, Ti reacts with O, Al and Si in the C _f /LAS composite material to form a compound to realize metallurgical connection; secondly, Ti and carbon fiber generate TiC , which improves the mechanical properties of the joint to a certain extent. By controlling the brazing temperature (860~940°C) and holding time (0~30min), the thickness of the reaction layer and the distribution of the reaction phase in the joint can be controlled, and then the brazing temperature can be controlled. The microstructure and properties of the welded joints were successfully connected with _Cf /LAS composites and reliable joints were obtained. The shear strength of the joint at room temperature can reach up to 8.4MPa, and the invention is mainly applied to connecting C _f /LAS composite materials with small size or simple shape to obtain components with large size or complex shape.

Example 1, a method for connecting C _f /LAS composite materials using AgCuTi solder, specifically completed according to the following steps: 1. Cut the C _f /LAS composite materials with a semi-automatic inner circle slicer to obtain C f /LAS composite materials to be connected _f /LAS composite material; 2. The connection surface of the C _f /LAS composite material to be connected obtained in step 1 was polished with sandpaper and then polished, and then the connection surface of the C _f /LAS composite material was ultrasonically cleaned in acetone for 5min~ 10min; 3. Place the AgCuTi solder between the connecting surfaces of the C _f /LAS composite material to be connected, and assemble it into an assembly of the C _f /LAS composite material/AgCuTi solder material/C _f /LAS composite material, wherein the AgCuTi The thickness of the solder foil is 25um~200um, and the Ti content is 1%~10%; 4. Place the assembly obtained in step 3 in a vacuum heating furnace. When the vacuum degree reaches (1.3~2.0)×10 ^-3 Pa , turn on the electricity to heat, control the heating rate at 10°C/min~30°C/min, raise the temperature to 860~940°C, then keep it warm for 0min~30min, then control the cooling rate at 3°C/min~10°C/min, and cool to 300 ℃, and then cool with the furnace. The present invention uses AgCuTi solder to connect C _f /LAS composite materials, and controls the thickness of the reaction layer by controlling the brazing temperature (860~940℃) and holding time (0~30min). And the distribution of the reactive phase in the joint, and then achieve the purpose of controlling the structure and performance of the joint, successfully realized the connection of C _f /LAS composites, and obtained a reliable joint. The room temperature shear strength of the joint can reach up to 8.4MPa.

Embodiment 2. The difference between this embodiment and embodiment 1 is that the thickness of the AgCuTi solder foil in step 3 is 50um~150um, and the Ti content is 3%~7%.

Embodiment 3. The difference between this embodiment and Embodiment 1 is that the thickness of the AgCuTi solder foil in step 3 is 100 um, and the Ti content is 4.5%.

Embodiment 4. The difference between this embodiment and Embodiment 1 is that the vacuum degree of the vacuum heating furnace reaches 1.5×10 ⁻³ Pa in Step 4.

Embodiment 5. The difference between this embodiment and Embodiment 1 is that in step 4, the heating rate is controlled to be 20° C./min.

Embodiment 6. The difference between this embodiment and Embodiment 1 is that the temperature is raised to 900° C. in step 4. Embodiment 7, the difference between this embodiment and embodiment 1 is: the holding time in step 4 is 5min~20min.

Embodiment 8. The difference between this embodiment and the above-mentioned embodiments is that the holding time in step 4 is 10 minutes.

Embodiment 9. The difference between this embodiment and embodiment 1 is that the cooling rate in step 4 is 5° C./min.

Example 10, a method of using AgCuTi solder to join C _f /LAS composite materials, specifically completed according to the following steps: 1. Cut the C _f /LAS composite materials with a semi-automatic inner circle slicer to obtain the C f /LAS composite materials to be connected _f /LAS composite material, wherein the size of the C _f /LAS composite material to be connected is 20mm×10mm×3mm and 5mm×5mm×5mm respectively; 2. The connection of the C _f /LAS composite material to be connected obtained in step 1 The surface was polished with sandpaper, and then the connecting surface of the C _f /LAS composite material was ultrasonically cleaned in acetone for 8 minutes; 3. The AgCuTi solder was placed between the connecting surfaces of the C _f /LAS composite material to be connected, and assembled Become the assembly of _Cf /LAS composite material/AgCuTi solder/ _Cf /LAS composite material, wherein the thickness of AgCuTi solder foil is 100um, and Ti content is 4.5%; Four, the assembly that step 3 obtains is placed on In the vacuum heating furnace, when the vacuum degree reaches 1.5×10 ^-3 Pa, turn on the electric heating, control the heating rate to 20°C/min, raise the temperature to 900°C, then keep it for 10 minutes, then control the cooling rate to 5°C/min, and cool to 300°C, and then cooling with the furnace, the method of connecting C _f /LAS composite materials with AgCuTi solder is completed.

The backscattered electron photo of the interfacial structure of the C _f /LAS composite material joint obtained in this example is shown in Figure 1. It can be seen from Figure 1 that the joint obtained by this embodiment is complete and dense, without defects such as cracks, and realizes Reliable bonding of _Cf /LAS composites. After testing, the average shear strength of the joint at room temperature reaches 8.4MPa.

Claims (5)

1. a method adopting AgCuTi solder to connect _Cf /LAS composite material is characterized in that the steps are as follows: Step 1. Machining the C _f /LAS composite material to obtain the C _f /LAS composite material to be connected; Step 2: Polish the connection surface of the C _f /LAS composite material to be connected obtained in step 1 with sandpaper, and then put the connection surface of the C _f /LAS composite material into an acetone solution for ultrasonic cleaning for 5 minutes to 10 minutes; Step 3, placing the AgCuTi solder between the connecting surfaces of the C _f /LAS composite materials to be connected, and assembling into an assembly in which the C _f /LAS composite material/AgCuTi solder/C _f/ LAS composite material are stacked in sequence, wherein The thickness of the AgCuTi solder foil is 25um~200um, and the Ti content is 1%~10%; Step 4. Place the assembly obtained in Step 3 in a vacuum heating furnace, and then evacuate it. When the vacuum degree reaches (1.3~2.0)×10 ^-3 Pa, turn on the electric heating again, and control the heating rate to 10°C/min~30 ℃/min, heat up to 860~940℃, then keep it warm for no more than 30min, then cool down, control the cooling rate at 3℃/min~10℃/min, cool down to 300℃ and then cool with the furnace, that is, the use of AgCuTi solder is completed connect. 2. A method for connecting C _f /LAS composite materials using AgCuTi solder according to claim 1, characterized in that in step 2, the sandpaper used to polish the connecting surface with sandpaper is 600# to 1000#. 3. A method for joining C _f /LAS composite materials with AgCuTi solder according to claim 1, characterized in that the concentration of the acetone solution in step 2 is ≥99.5%. 4. A method for joining C _f /LAS composite materials using AgCuTi solder according to claim 1, characterized in that the thickness of the AgCuTi solder foil described in step 3 is 100um, and the Ti content is 4.5%. 5. A method of using AgCuTi solder to join C _f /LAS composite materials according to claim 1, characterized in that in step 4, the vacuum degree of the vacuum heating furnace reaches 1.5×10 ^-3 Pa, and the heating rate is controlled to be 20°C /min, the temperature is raised to 900°C, the holding time is 10min, and the cooling rate is 5°C/min.