CN111761827A - A kind of carbon fiber reinforced resin matrix composite material joining process method - Google Patents

Abstract

The invention discloses a connection process method for carbon fiber reinforced resin-based composite materials. Ultraviolet pulsed laser beams are used to scan the bonding surface of carbon fiber-reinforced resin-based composite materials, the surface resin layer is removed, the carbon fiber layer is exposed, and cleaning and drying are performed; Apply glue on the bonding surface and carry out bonding; apply ultrasonic vibration with a frequency of 15KHz to 25KHz to the vertical direction of the bonding surface through the ultrasonic vibration tool head, apply a pre-pressure of 1MPa to 5MPa through the ultrasonic vibration tool head before vibration, and end the holding pressure of 15 ～30min; heat and cure the glued parts at 40℃～80℃ for 1～20h. The invention combines ultrasonic vibration-assisted bonding with laser surface treatment and modification of the adhesive by using carbon nanotubes for the first time, and effectively solves the problems of poor bonding quality, uneven bonding quality, and adhesive bonding caused by carbon fiber bonding in practical engineering. The problem of carbon fiber filaments breaking due to surface treatment before sticking.

Description

A kind of carbon fiber reinforced resin matrix composite material joining process method

technical field

The invention belongs to the technical field of materials, and in particular relates to a connection process method for carbon fiber reinforced resin-based composite materials.

Background technique

With the vigorous development of the automobile industry, energy saving and environmental protection are more and more taken into account in the manufacturing process of automobiles. Research shows that the weight of the automobile is reduced by 1%, and the fuel consumption is reduced by 0.7%. The volume can be reduced by 0.3 to 0.6L, and the exhaust emission is also reduced accordingly.

Carbon fiber reinforced resin matrix composites have been widely used in many engineering fields in recent years due to their high strength, low density, good thermal stability, and good preparation performance, and have become the focus of new material research. Compared with the traditional mechanical connection of composite materials (bolt connection, riveting), the glue connection uses the adhesive to connect the parts, without damage to the composite material, without the stress concentration of openings, with strong bearing capacity, uniform stress distribution, preventing The advantages of electrochemical corrosion, etc. Therefore, glue connection is more widely used in the connection design of carbon fiber advanced composite materials than mechanical connection, and it has become one of the key technologies to realize the lightweight of automobiles. However, the problems of poor bonding quality and uneven distribution of bonding strength have not been well resolved.

Ultrasonic vibration-assisted bonding technology has become a research direction of extensive attention in recent years. Compared with the traditional bonding process, the cavitation effect generated by ultrasonic vibration in the liquid phase has the effect of inducing seam filling and interfacial moisturization, which can significantly improve the bonding quality. , to improve the problem of uneven distribution of bonding strength.

At present, the method to improve the bonding strength of carbon fiber reinforced resin matrix composites is mainly by improving the bonding surface treatment process, such as grinding, sandblasting, shot peening, coupling, etc., improving the component ratio of the adhesive, and changing the adhesive. curing process, etc. However, human factors have a great influence on the gluing process. Process factors such as uneven grinding and uneven gluing will cause large differences in the bonding strength of the samples. Sandblasting, shot peening, coupling and other processes are complicated and increase costs. It is difficult to apply uniform molding pressure so that the adhesive can sufficiently wet the surfaces to be bonded, and these factors make it difficult to obtain stable and reliable bonded samples with high bond strength.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a connection process method of carbon fiber reinforced resin matrix composite materials, which aims to improve the surface quality of the bonding surface of carbon fiber reinforced resin matrix composite materials, improve the contact area between the adhesive and the bonding surface, and then improve the ultrasonic vibration auxiliary glue connection strength and quality.

In order to achieve the above purpose, the technical solutions are as follows:

A carbon fiber reinforced resin matrix composite material connection process method, comprising the following steps:

1) Scan the bonding surface of the carbon fiber reinforced resin matrix composite material with an ultraviolet pulsed laser beam, remove the surface resin layer and expose the carbon fiber layer, and carry out cleaning and drying treatment;

2) After fixing the laser-treated carbon fiber reinforced resin-based composite material, apply glue to the bonding surface and carry out bonding; the adhesive preparation method used is as follows: the carbon nanotubes are mixed with ethyl acetate and dispersed by ultrasonic vibration for 45min-90min, Add epoxy resin components and continue to disperse by ultrasonic vibration for 45min-90min, then remove ethyl acetate, add epoxy resin curing agent and mix evenly;

3) Apply ultrasonic vibration with a frequency of 15KHz to 25KHz to the vertical direction of the bonding surface through the ultrasonic vibration tool head, apply a pre-pressure of 1MPa to 5MPa through the ultrasonic vibration tool head before the vibration, and maintain the pressure for 15min to 30min after the ultrasonic vibration;

4) Heat and cure the glued parts at 40℃～80℃ for 1～20h.

According to the above scheme, the ultraviolet pulsed laser used in step 1 is an ultraviolet laser with a wavelength of 193nm～355nm, the photon energy is 3.49eV～6.44eV, the average power is 15w～200w, the repetition frequency is 1MH～2MHz, and the spot diameter is 1.3mm～1.5 mm, the scanning speed is 50mm/s～1500mm/s.

According to the above scheme, the scanning direction of the ultraviolet pulsed laser beam in step 1 and the direction of the outermost fiber of the carbon fiber reinforced resin matrix composite material are at 45°.

According to the above scheme, during the preparation process of the adhesive described in step 2, the ultrasonic vibration dispersion was stopped every 15 minutes and the stirring was carried out for 5 minutes, and the temperature was kept at 25°C to 35°C; the mass percentage of carbon nanotubes in the adhesive was 0.2%- 1%.

According to the above scheme, the thickness of the adhesive layer in step 2 is between 0.7mm and 0.8mm.

According to the above scheme, in step 2, the ultrasonic vibration amplitude is 10 μm to 100 μm, and the amplitude percentage is 50% to 100%.

The beneficial effects of the present invention are:

A carbon fiber reinforced resin-based composite material connection process method of the present invention combines ultrasonic vibration-assisted bonding with laser surface treatment and modification of the adhesive with carbon nanotubes for the first time, which effectively solves the problem of carbon fiber bonding in practical engineering. The adhesive quality is not good, the adhesive quality is uneven, and the carbon fiber filament is broken by the surface treatment before the adhesive.

The invention has high precision and stable surface quality, and changes the spatial arrangement of the carbon fiber filaments through ultrasonic vibration. At the same time, the carbon fiber filaments will also vibrate to a certain extent under the action of ultrasonic vibration, so that the carbon nanotubes gather in the gaps of the carbon fiber filaments to form crossovers. The networked mechanical latch structure enables the adhesive to better bond the carbon fiber filaments; in addition, the ultrasonic vibration also changes the direction of the flow field of the adhesive layer, so that the carbon nanotubes are oriented and arranged, and the surface of the carbon nanotubes is arranged. Covalent bonds are formed between the free groups and the epoxy resin adhesive molecules, which enhances the performance of the adhesive, improves the bonding strength and improves the bonding strength.

The method is suitable for automated and industrialized production.

Detailed ways

The following examples further illustrate the technical solutions of the present invention, but are not intended to limit the protection scope of the present invention.

The process flow of the carbon fiber reinforced resin matrix composite material connection process method of the present invention is as follows:

In step S100, the surface of the carbon fiber reinforced resin matrix composite material is cleaned, and the cleaned bonding area of the carbon fiber reinforced resin matrix composite material is treated by picosecond laser to remove the surface resin and expose the inner carbon fiber layer.

Step S200, adding a certain mass fraction of carbon nanotubes to the adhesive by using a solution mixing method.

Step S300, the carbon fiber reinforced resin matrix composite material is put into the positioning fixture, and the adhesive surface is treated with glue.

In step S400, ultrasonic vibration of a certain frequency is applied to the carbon fiber reinforced resin matrix composite material by an ultrasonic vibration tool head.

In step S500, the ultrasonic vibration is stopped, the ultrasonic vibration tool head is raised, and the adhesive joint is placed in an oven for heating and curing.

Example 1

Step 1: Scan the bonding surface of the carbon fiber reinforced resin matrix composite material with an ultraviolet pulsed laser beam, remove the surface resin layer and expose the carbon fiber layer, and perform cleaning and drying treatment. The relevant laser parameters are: wavelength 355nm, photon energy 3.49ev, average power 30w, repetition frequency 1MHz, spot diameter 1.3mm, scanning speed 1500mm/s, and the scanning direction is in the direction of the outermost fiber of the carbon fiber reinforced resin matrix composite material. 45°.

Step 2: Mix 0.2wt% carbon nanotubes and ethyl acetate for 45min by ultrasonic vibration dispersion, add epoxy resin components and continue ultrasonic vibration dispersion for 45min, put into a vacuum drying box to remove ethyl acetate, add epoxy resin resin curing agent and mix well.

Step 3: Put the carbon fiber reinforced resin-based composite material into the positioning fixture, and apply glue on the bonding surface, and the thickness of the glue layer is 0.7mm.

Step 4: applying ultrasonic vibration of a certain frequency to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head. Among them, the ultrasonic frequency is 15KHz, the amplitude is 10μm, and the amplitude percentage is 70%. Before the vibration, a pre-pressure of 1MPa is applied to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head, and the pressure is maintained for 15min after the vibration.

Step 5: Stop the ultrasonic vibration, raise the ultrasonic vibration tool head, put the glue joint into the oven, and heat and cure it at 40°C for 20h.

According to ASTM D5868-01, the tensile test was performed on the single lap specimen, and the shear strength of the specimen was 12.08 MPa.

Example 2

Step 1: Scan the bonding surface of the carbon fiber reinforced resin matrix composite material with an ultraviolet pulsed laser beam, remove the surface resin layer and expose the carbon fiber layer, and perform cleaning and drying treatment. The relevant laser parameters are: wavelength 193nm, photon energy 6.44ev, average power 15w, repetition frequency 1.2MHz, spot diameter 1.5mm, scanning speed 800mm/s, scanning direction and the outermost fiber direction of the carbon fiber reinforced resin matrix composite material at 45°.

Step 2: Mix 0.5wt% carbon nanotubes and ethyl acetate for 60 minutes of ultrasonic vibration dispersion, add epoxy resin components, continue ultrasonic vibration dispersion for 60 minutes, put into a vacuum drying box to remove ethyl acetate, add epoxy resin resin curing agent and mix well.

Step 3: Put the carbon fiber reinforced resin-based composite material into the positioning fixture, and apply glue on the bonding surface, and the thickness of the glue layer is 0.7mm.

Step 4: applying ultrasonic vibration of a certain frequency to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head. Among them, the ultrasonic frequency is 15KHz, the amplitude is 32μm, and the amplitude percentage is 70%. Before the vibration, a pre-pressure of 1MPa is applied to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head, and the pressure is maintained for 15min after the vibration.

Step 5: Stop the ultrasonic vibration, raise the ultrasonic vibration tool head, put the glue joint into the oven, and heat and cure it at 40°C for 20h.

According to ASTM D5868-01, the tensile test was performed on the single lap specimen, and the shear strength of the specimen was 8.93 MPa.

Example 3

Step 1: Scan the bonding surface of the carbon fiber reinforced resin matrix composite material with an ultraviolet pulsed laser beam, remove the surface resin layer and expose the carbon fiber layer, and perform cleaning and drying treatment. The relevant laser parameters are: wavelength 355nm, photon energy 3.49ev, average power 30w, repetition frequency 1MHz, spot diameter 1.5mm, scanning speed 50mm/s, and the scanning direction is in the direction of the outermost fiber of the carbon fiber reinforced resin matrix composite material. 45°.

Step 2: Mix 0.75 wt% carbon nanotubes and ethyl acetate for 75 minutes of ultrasonic vibration dispersion, add epoxy resin components, continue ultrasonic vibration dispersion for 75 minutes, put into a vacuum drying box to remove ethyl acetate, add epoxy resin resin curing agent and mix well.

Step 3: Put the carbon fiber reinforced resin-based composite material into the positioning fixture, and apply glue on the bonding surface, and the thickness of the glue layer is 0.76mm.

Step 4: applying ultrasonic vibration of a certain frequency to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head. Among them, the ultrasonic frequency is 15KHz, the amplitude is 24μm, and the amplitude percentage is 70%. Before the vibration, a pre-pressure of 5MPa is applied to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head, and the pressure is maintained for 15min after the vibration.

Step 5: Stop the ultrasonic vibration, raise the ultrasonic vibration tool head, put the glue joint into the oven, and heat and cure it at 80°C for 3 hours.

According to ASTM D5868-01, the tensile test was carried out on the single lap specimen, and the shear strength of the specimen was 24.48MPa.

Example 4

Step 1: Scan the bonding surface of the carbon fiber reinforced resin matrix composite material with an ultraviolet pulsed laser beam, remove the surface resin layer and expose the carbon fiber layer, and perform cleaning and drying treatment. The relevant laser parameters are: wavelength 355nm, photon energy 3.49ev, average power 200w, repetition frequency 2MHz, spot diameter 1.5mm, scanning speed 300mm/s, and the scanning direction is in the direction of the outermost fiber of the carbon fiber reinforced resin matrix composite material. 45°.

Step 2: Mix 0.75wt% carbon nanotubes and ethyl acetate for 60 minutes of ultrasonic vibration dispersion, add epoxy resin components, continue ultrasonic vibration dispersion for 75 minutes, put into a vacuum drying box to remove ethyl acetate, add epoxy resin resin curing agent and mix well.

Step 3: Put the carbon fiber reinforced resin-based composite material into the positioning fixture, and apply glue on the bonding surface, and the thickness of the glue layer is 0.8mm.

Step 4: applying ultrasonic vibration of a certain frequency to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head. Among them, the ultrasonic frequency is 20KHz, the amplitude is 20μm, and the amplitude percentage is 50%. Before the vibration, a pre-pressure of 3MPa is applied to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head, and the pressure is maintained for 20min after the vibration.

Step 5: Stop the ultrasonic vibration, raise the ultrasonic vibration tool head, put the adhesive part into the oven, and heat and cure it at 80°C for 1 hour.

According to ASTM D5868-01, the tensile test was carried out on the single lap specimen, and the shear strength of the specimen was 22.58MPa.

Example 5

Step 1: Scan the bonding surface of the carbon fiber reinforced resin matrix composite material with an ultraviolet pulsed laser beam, remove the surface resin layer and expose the carbon fiber layer, and perform cleaning and drying treatment. The relevant laser parameters are: wavelength 248nm, photon energy 4.96ev, average power 100w, repetition frequency 1.6MHz, spot diameter 1.4mm, scanning speed 200mm/s, scanning direction and the outermost fiber direction of the carbon fiber reinforced resin matrix composite material at 45°.

Step 2: Mix 1 wt % of the adhesive mass of carbon nanotubes with ethyl acetate for ultrasonic vibration dispersion for 90 minutes, add epoxy resin components and continue ultrasonic vibration dispersion for 90 minutes, put them in a vacuum drying box to remove ethyl acetate, add epoxy resin hardener and mix well.

Step 3: Put the carbon fiber reinforced resin-based composite material into the positioning fixture, and apply glue on the bonding surface, and the thickness of the glue layer is 0.8mm.

Step 4: applying ultrasonic vibration of a certain frequency to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head. Among them, the ultrasonic frequency is 25KHz, the amplitude is 100 μm, and the amplitude percentage is 100%. Before the vibration, a pre-pressure of 5 MPa is applied to the carbon fiber reinforced resin matrix composite material through the ultrasonic vibration tool head, and the pressure is maintained for 15 min after the vibration.

Step 5: Stop the ultrasonic vibration, raise the ultrasonic vibration tool head, put the glue joint into the oven, and heat and cure it at 60°C for 8 hours.

According to ASTM D5868-01, the tensile test was carried out on the single lap specimen, and the shear strength of the specimen was 16.34 MPa.

According to the results of the above examples, the shear strength of the single lap joint of Example 3 is the largest, which is 24.48MPa. The following is a further description of the promoting effect of this process method on bonding strength in conjunction with the comparative example of Example 3.

Comparative Example 1

Relative to Example 3, Comparative Example 1 did not add carbon nanotubes, and steps 1, 3, 4, and 5 were exactly the same as the corresponding steps in the embodiment. According to ASTM D5868-01, a tensile test was performed on the single-lap sample, The shear strength of the obtained sample was 5.38 MPa. Adding a certain mass fraction of carbon nanotubes increases the shear strength by about 350%.

Comparative Example 2

Compared with Example 3, in Comparative Example 2, no laser scanning treatment was performed on the bonding surface, and steps 2, 3, 4, and 5 were exactly the same as the corresponding steps in the embodiment. The tensile test showed that the shear strength of the sample was 7.01MPa. Laser scanning treatment of the bonded surface increased shear strength by approximately 250%.

Comparative Example 3

Compared with Example 3, in Comparative Example 2, the sample to be bonded is not subjected to ultrasonic vibration treatment, and steps 1, 2, 3, and 5 are exactly the same as the corresponding steps in the embodiment. According to ASTM D5868-01, the single-lap sample is The tensile test was carried out, and the shear strength of the sample was obtained as 17.75MPa. Ultrasonic vibration treatment of the samples to be bonded increases the shear strength by about 38%.

The above-mentioned example is only an embodiment of the present invention, and several improvements and optimizations can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims (6)

1. a carbon fiber reinforced resin matrix composite material connection process method is characterized in that comprising the following steps: 1) Scan the bonding surface of the carbon fiber reinforced resin matrix composite material with an ultraviolet pulsed laser beam, remove the surface resin layer and expose the carbon fiber layer, and carry out cleaning and drying treatment; 2) After fixing the laser-treated carbon fiber reinforced resin-based composite material, apply glue to the bonding surface and carry out bonding; the adhesive preparation method used is as follows: the carbon nanotubes are mixed with ethyl acetate and dispersed by ultrasonic vibration for 45min-90min, Add epoxy resin components and continue to disperse by ultrasonic vibration for 45min-90min, then remove ethyl acetate, add epoxy resin curing agent and mix evenly; 3) Apply ultrasonic vibration with a frequency of 15KHz to 25KHz to the vertical direction of the bonding surface through the ultrasonic vibration tool head, apply a pre-pressure of 1MPa to 5MPa through the ultrasonic vibration tool head before the vibration, and maintain the pressure for 15min to 30min after the ultrasonic vibration; 4) Heat and cure the glued parts at 40℃～80℃ for 1～20h. 2. The carbon fiber reinforced resin-based composite material connection process method according to claim 1, wherein the ultraviolet pulse laser used in step 1 is an ultraviolet laser with a wavelength of 193nm～355nm, the photon energy is 3.49eV～6.44eV, and the average power is 15w ～200w, repetition frequency is 1MH～2MHz, spot diameter is 1.3mm～1.5mm, scanning speed is 50mm/s～1500mm/s. 3 . The method for connecting carbon fiber reinforced resin matrix composite materials according to claim 1 , wherein the scanning direction of the ultraviolet pulsed laser beam in step 1 and the direction of the outermost fiber of the carbon fiber reinforced resin matrix composite material are at 45°. 4 . 4. The carbon fiber reinforced resin matrix composite material connection process method according to claim 1, characterized in that in the preparation process of the adhesive in step 2, the ultrasonic vibration is stopped every 15min to disperse and stir for 5min, and the temperature is maintained at 25 ℃～35 ℃. ℃; the mass percentage of carbon nanotubes in the adhesive is 0.2%-1%. 5 . The carbon fiber reinforced resin matrix composite material connection process method according to claim 1 , wherein the thickness of the adhesive layer in step 2 is between 0.7 mm and 0.8 mm. 6 . 6 . The method for connecting carbon fiber reinforced resin matrix composite materials according to claim 1 , wherein the ultrasonic vibration amplitude in step 3 is 10 μm to 100 μm, and the amplitude percentage is 50% to 100%. 7 .