KR19980055640A - Composite preform and its manufacturing method - Google Patents

Abstract

The present invention relates to a composite preform and a method for manufacturing the same, and more particularly, to place the continuous fiber in the center of the connecting rod, and to wrap the short fiber or whisker product around the continuous fiber, The present invention relates to a preform for connecting composite rods having improved rigidity and strength by manufacturing a preform in a form of reinforcing part, and a method of manufacturing the preform.

Description

Composite preform and its manufacturing method

The present invention relates to a composite preform and a method for manufacturing the same, and more particularly, to place the continuous fiber in the center of the connecting rod, and to wrap the short fiber or whisker product around the continuous fiber, The present invention relates to a preform for connecting composite rods having improved rigidity and strength by manufacturing a preform in a form of reinforcing part, and a method of manufacturing the preform.

In general, silicon carbide, alumina, or silicon nitride has a very high level of strength, elastic modulus, heat resistance, and chemical stability, and thus is usefully used as a reinforcing material for metal or plastic composites.

Methods of manufacturing preforms for composite connecting rods of conventional automobiles using these reinforcing materials have been disclosed in Japanese Patent Laid-Open No. 2-195012, US Patent No. 4,357,989 and British Patent GB 2129342A. The method disclosed in 195012 is a form of reinforcing the entire connecting rod consisting of a large end, a small end, and a main body with a silicon carbide (SiC) whisker. However, in this case, there is a disadvantage that the strength, in particular, high temperature strength, which is a weak point of the whisker reinforced composite material.

In addition, the method disclosed in US Patent No. 4,357, 989 is to reinforce only the main body of the connecting rod by arranging the continuous fibers in a row using a rod-shaped pipe as a support. The connecting rod manufactured as described above has a problem in that the strength of the connecting rod is improved but the rigidity is small, and the rod-shaped pipe support must be used.

In addition, in the case of British Patent G.B 2129342A, specific fibers are inserted into a quartz tube and then sintered to use, and a special support is required to fix the molded body in a mold. These quartz tubes and supports do not serve as reinforcing agents in the composite material, but exist as foreign substances, and since only continuous fibers are used, there is little improvement in rigidity.

In addition, a method of manufacturing a composite connecting rod by forging a titanium alloy of Ti-6Al-4V has been disclosed, which is expensive and inexpensive. In addition, Ford and Toyota have disclosed a method of manufacturing a connecting rod by sintering and forging using Fe-Cu-C-S alloy powder, but since iron powder is used, it is not preferable because of heavy weight.

The present invention is to disperse short fibers and whiskers in order to solve the problem of the method of manufacturing a preform in manufacturing a connecting rod such as a composite connecting rod as described above, and then add an inorganic binder, an organic binder, a quaternizing agent to form a suspension. After the preparation and injection into the mold for preparing a preform, the continuous fiber strand is placed in the center of the connecting rod by adding the continuous fiber strand cut into a predetermined length to the suspension by drying the continuous fiber strand soaked in an organic binder. The purpose of the present invention is to provide a composite preform capable of reinforcing stiffness and strength by forming a circumference of a continuous fiber.

The present invention is characterized by a composite preform consisting of continuous fibers and short fibers or whisker products.

In addition, the present invention is a process of mixing 30,000 to 50,000 strands of continuous fiber cut to the length of the connecting rod with an organic binder and drying the rod into a rod, and separately dispersing short fibers or whisker products, and then adding an inorganic binder, an organic binder and a flocculant. And a process for preparing a suspension, and a method of preparing a preform comprising a step of injecting the suspension half into a mold and then injecting the rod-like continuous fiber into the mold and then injecting the remaining suspension into the mold.

The present invention will be described in more detail as follows.

In the present invention, the continuous fiber is selected from alumina continuous fiber, carbon continuous fiber and boron continuous fiber. The diameter of the continuous fibers is preferably 5 to 25 μm, and the continuous fibers are cut to the length of the connecting rod, and 30,000 to 50,0000 strands are wetted with an organic binder and dried in a rod to prepare rod-shaped continuous fibers. .

Meanwhile, the short fiber or whisker product for reinforcing rigidity is a short fiber or whisker product selected from SiC, Si ₃ N ₄ , 9Al ₂ O ₃ · 2B ₂ O _3, and Al ₂ O ₃ whiskers. After dispersing in distilled water, an inorganic binder, an organic binder and a flocculant are added thereto. Then, the acidity is adjusted to 4-5 with hydrochloric acid and stirred, and then a small amount of silicon emulsion is added to the antifoaming agent to prepare a suspension.

In the present invention, colloidal silica is used as the inorganic binder, cationic starch is used as the organic binder, and polycrymin is used as the coagulant.

Then, the prepared suspension is injected by only half of the mold for preparing the preform, and the rod-like continuous fiber bundle is placed thereon. This causes short fibers or whiskers agglomerated in the suspension, or a portion of these mixed agglomerates, to be deposited at the bottom of the mold, whereby a bundle of continuous fibers is settled and placed on the deposit.

The remaining suspension is then injected into a mold for making preforms, which are then deposited on a bundle of continuous fibers, followed by dewatering in a vacuum filtrate to form the preforms for connecting rods in the wet state.

The preform in the demolded wet state is preliminarily dried at 100 ° C. for 12 hours, and then heated at 900 to 1,100 ° C. for about 1 hour to prepare the preform.

In the present invention, the content of the organic binder, the inorganic binder, the flocculant, the antifoaming agent, and the like is usually the same as or similar to that of the preparation of the composite preform, and other provisional tablet conditions are similar.

The preform manufactured as described above has a very high level of strength, elastic modulus, heat resistance, and chemical stability of the short fibers or whiskers forming the outer shape of the preform, and thus can be usefully used as a reinforcing material for composite materials. In addition to acting as a support for arranging the continuous fibers on the center in the direction and at the same time to fix the preform to the mold, there is no need to use a separate fixing jig as in the prior art.

Hereinafter, the present invention will be described in detail with reference to the following Examples, but the present invention is not limited by the Examples.

Example 1

45,000 strands of alumina continuous fiber (produced by Nippon Shuto Chemical Co., Ltd.) having a specific gravity of 3.25 mg / m 2 and a diameter of 17 μm were cut from the end of the connecting rod to the end of the small end and soaked in a 0.5% solution of cationic starch. . At this time, the shape of the continuous fiber was dried in a straight warpage form.

Separately, 60 g of alumina short fibers (product of Icy, UK) having a specific gravity of 3.4 mg / m 2, diameter of 3 μm, and length of 50 to 100 μm were dispersed in 1 L of distilled water, and then 1% of colloidal silica was added. After adding 0.5% of cationic starch and 0.1% of polycrimine, the acidity was adjusted to 4-5 with hydrochloric acid, followed by stirring for 2 minutes at 2,000 rpm. To this was added 0.002% of a silicon emulsion, followed by stirring at 20 rpm for 30 seconds in a vacuum vessel to remove bubbles in the suspension. Such a suspension was injected into the mold installed in the vacuum filtrate dewatering device about 1/2 to dehydrate water about 2/3.

At this time, the continuous fiber bundle prepared above was placed in the mold so as to be located at the center of the connecting rod, and then the remaining suspension was injected, followed by the lowering of the flat punch while dehydrating water under vacuum to complete molding into the preform for the connecting rod. After molding into a wet preform, the mold was demolded, preliminarily dried at 100 ° C. for 12 hours, and heated at 1,000 ° C. for 1 hour to prepare a preform.

Example 2

A composite material preform was prepared in the same manner as in Example 1 except that 46,000 strands of SiC continuous fibers (specific gravity 2.25 mg / m 2, diameter 15 μm, manufactured by Kabon, Japan) were used, and alumina was used as a short fiber. Composite preforms were prepared using short fibers (specific gravity 3.4 mg / m 2, diameter 3 μm, length 50-100 μm, manufactured by Icy, UK).

Example 3

A composite material preform was prepared in the same manner as in Example 1, except that 45,000 strands of alumina continuous fiber (specific gravity 3.25 mg / m 2, diameter 17 μm, manufactured by Nippon Shuto Chemical Co., Ltd.) were used as short fibers. _{9Al 2 O 3 · 2B 2 O} 3 whiskers was prepared in the composite preform with the (specific gravity 2.94 mg / ㎡, 0.5~1.0 ㎛ diameter, length 10~30 ㎛, British children C. I. Corp.).

Example 4

A composite material preform was prepared in the same manner as in Example 1 except that 46,000 strands of SiC continuous fibers (specific gravity 2.25 mg / m 2, diameter 15 μm, manufactured by Kabon, Japan) were used, and 9Al was used as a short fiber. ₂ O ₃ · 2B ₂ O ₃ whiskers was prepared in the composite preform with the (specific gravity 2.94 mg / ㎡, 0.5~1.0 ㎛ diameter, length 10~30 ㎛, British children C. I. Corp.).

Example 5

A composite material preform was prepared in the same manner as in Example 1, except that 45,000 strands of alumina continuous fiber (specific gravity 3.25 mg / m 2, diameter 17 μm, manufactured by Nippon Shuto Chemical Co., Ltd.) were used as short fibers. Composite preforms were prepared using silicon carbide whiskers (specific gravity 3.22 mg / m 2, diameter 0.5-1.0 μm, length 50-500 μm, manufactured by Japan East Sea Carbon Co., Ltd.).

Example 6

A composite material preform was prepared in the same manner as in Example 1, except that 46,000 strands of SiC continuous fibers (specific gravity 2.25 mg / m 2, diameter 15 μm, manufactured by Kabon, Japan) were used as carbon fibers as short fibers. Composite preforms were prepared using silicon whiskers (specific gravity 3.22 mg / m 2, diameter 0.5-1.0 μm, length 50-500 μm, manufactured by East Sea Carbon, Japan).

Example 7

A composite material preform was prepared in the same manner as in Example 1, except that 46,000 strands of alumina continuous fiber (specific gravity 3.25 mg / m 2, diameter 17 μm, manufactured by Nippon Shuto Chemical Co., Ltd.) were used as short fibers. using the Si ₃ N ₄ whiskers (density 3.18 mg / ㎡, 0.1~1.6 ㎛ diameter, length 20~200 ㎛, Japan taebo other chemical method, Inc.) to prepare a composite preform.

Example 8

A composite material preform was prepared in the same manner as in Example 1, except that 46,000 strands of SiC continuous fibers (specific gravity 2.25 mg / m 2, diameter 15 μm, manufactured by Kabon, Japan) were used as continuous fibers, and Si was used as short fibers. ₃ N ₄ by using the whiskers (density 3.18 mg / ㎡, 0.1~1.6 ㎛ diameter, length 20~200 ㎛, Japan taebo other chemical method, Inc.) to prepare a composite preform.

Comparative Example 1

60,000 strands of SiC continuous fiber (specific gravity 2.25 mg / m 2, diameter 15 μm, manufactured by Kabon, Japan) were cut from the end of the connecting rod to the end of the small end, and these fibers were cut in a quartz tube according to British Patent GB 2129342A. It was put in and then sintered to prepare a preform.

Comparative Example 2

60,000 strands of alumina continuous fiber (specific gravity 3.25 mg / m2, diameter 17 탆, manufactured by Nippon Chemical Co., Ltd.) were cut from the end of the large end of the connecting rod to the length of the end of the small end, and these fibers were quartz according to GB 2129342A. It was put in a tube and then sintered to prepare a preform.

Comparative Example 3

A preform of a connecting rod was prepared in a form similar to that of Japanese Patent No. Hei 2-195012, reinforced only with SiC whiskers.

100 g of SiC whisker (Donghae Carbon Co., Ltd.) having a diameter of 0.5 to 1.0 µm and a length of 50 to 500 µm was dispersed in 1 liter of distilled water, and then 1% of colloidal silica was added, 0.5% of cationic starch and 0.1 of polycrimin After adding%, the acidity was adjusted to 4-5 with hydrochloric acid and stirred at 2,000 rpm for 2 minutes. After adding 0.002% of the silicon emulsion thereto, the mixture was stirred at 20 rpm for 30 seconds in a vacuum vessel to remove bubbles in the suspension. Such suspension was injected into the mold installed in the vacuum filtrate dehydrator, and the water leveling punch was lowered while dehydrating water under vacuum to complete molding into a preform for connecting rods. After molding into a wet preform, the mold was demolded, preliminarily dried at 100 ° C. for 12 hours, and heated at 1,000 ° C. for 1 hour to prepare a preform.

Experimental Example 1

The aluminum composite connecting rod was manufactured by high pressure casting using the preforms prepared according to Examples 1 to 8 and Comparative Examples 1 to 3. At this time, the pre-form was heated to 400 ℃ by using AC4C aluminum alloy as a base metal, and then placed in a high-pressure casting mold preheated to 360 ℃, and cast, and injected with aluminum molten metal heated to 860 ℃ Pressurized to 100 MPa. At this time, the pressing speed was set to 2.8 mm / sec. The performance of the connecting rods prepared in this way was compared by a fatigue test of repeated compression and tension.

The fatigue test was carried out at 150 ° C, and the basic load of -0.9 kN (extrusion load) was given, followed by the repeated +42 kN (tensile load) and -42 kN (compression load). In addition, the tensile strength was measured by making a tensile test specimen in the center of the connecting rod.

The tensile strength at the center of the connecting rod and the high temperature fatigue limit of the connecting rod were measured as shown in Table 1 below.

division Tensile strength at connecting rod center (kg / ㎡) Connecting rod high temperature fatigue limit (× 10 ⁵ ) Example 1 78 1.8 Example 2 72 1.6 Example 3 89 2.0 Example 4 84 2.1 Example 5 92 2.94 Example 6 88 3.67 Example 7 90 2.9 Example 8 89 2.58 Comparative Example 1 57 0.07 Comparative Example 2 58 0.11 Comparative Example 3 42 0.002

The preform manufactured according to the present invention not only has excellent strength and rigidity, but also has excellent elastic modulus, heat resistance, and chemical stability due to the properties of the original reinforcing material, and thus can be usefully used as a reinforcing material for composite materials. There is no need for fixing jig, there is no troublesome process.

Claims (4)

Composite preform comprising a continuous fiber and a short fiber or whisker product. The composite material preform according to claim 1, wherein the continuous fiber is selected from alumina continuous fiber, carbon continuous fiber and boron continuous fiber. The preliminary composite material according to claim 1, wherein the short fiber or whisker product is a short fiber or whisker product selected from SiC, Si ₃ N ₄ , 9Al ₂ O ₃ · 2B ₂ O ₃ and Al ₂ O ₃ whiskers. Molded body. 30,000-50,000 strands of continuous fibers cut to the length of the connecting rod are mixed with an organic binder and dried in a rod form. Separately, short fibers or whisker products are dispersed, and then an inorganic binder, an organic binder and a flocculant are added to prepare a suspension. And a step of injecting the suspension half into the mold, and then injecting the rod-like continuous fiber into the mold, and then injecting the remaining suspension into the mold.