JPS60141847A - Fiber-reinforced composite metallic material - Google Patents

Abstract

PURPOSE:To extend the industrial use of the titled material by embedding a fibrous aggregate which is a mixture of staple fibers with whiskers in a metallic matrix so as to compensate for the defects of fiber reinforcement with the whiskers while making use of the advantages. CONSTITUTION:A fibrous aggregate is embedded in a metallic matrix to obtain a fiber reinforced composite metallic material FRM. The fibrous aggregate is a mixture of staple fibers with whiskers, and it is formed by growing the whiskers on the surfaces of the staple fibers from an introduced gaseous starting material by heating. The whiskers compensate for the defects of fiber reinforcement while making use of the advantages, so the industrial use of the material FRM is extended.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a fiber reinforced metal composite material (hereinafter referred to as FRM) in which fiber aggregates are embedded in a metal matrix.
Regarding improvements.

[Prior Art] Recently, as FRMs, fiber-reinforced FRMs reinforced with fibers and whisker-reinforced FRMs reinforced with whiskers have been provided. Both have their own advantages, but they also have disadvantages, which limits their industrial use.

For example, carbon 88 reinforced FRM, which is a typical example of the former,
The advantages and disadvantages of FRM reinforced with silicon carbide (SiC) whiskers, which is a typical example of the latter, are as follows. In other words, the advantages of carbon fiber-reinforced FRM are that it has a lower specific gravity than SiC whisker-reinforced FRM, has good machinability, and is inexpensive. Compared to whisker-reinforced FRM, the strength and hardness are lower, and the formability of the fibrous body is poor.On the other hand, the advantages of SiC whisker-reinforced FRM are that it has greater strength and hardness, and has less wear. The fibrous body has good formability, but its disadvantages are that it has a high specific gravity, making it difficult to reduce weight, has poor machinability, and has extremely low whisker productivity, making the price lower than that of carbon fibers. It is very expensive, about 10 times as expensive as mH.

As described above, carbon fiber reinforced FRM and silicon carbide whisker reinforced FRM have contradictory advantages and disadvantages.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances. An object of the present invention is to provide an FRM that can be widely used industrially.

[Structure of the Invention] The FRM of the present invention is a fiber-reinforced metal composite material in which a fiber aggregate is embedded in a metal matrix, in which the fiber aggregate is composed of a mixture of short fibers and whiskers. This is a characteristic feature.

A whisker is a sword-shaped or rod-shaped crystal called a whisker crystal with a diameter of μ units, and is usually a single crystal. Whiskers have the same density and molten temperature as those of the same composition, but because they have no or almost no defects such as twins or kinks, they have a strength that is at or close to the theoretical strength, and a whisker of the same composition. It has significantly greater strength than other materials. Specifically, even with the same composition, the normal strength is 1oO ~
It has an extremely strong strength of 1000 times.

The whisker is preferably a ceramic whisker.

This is because ceramic has a lower specific gravity and higher tensile strength than metal whiskers. In addition, a large number of whiskers can be grown in a flocked or feather-like manner on the surface of short fibers by chemical means described below. Ceramic whiskers include silicon carbide (S i C) whiskers, silicon nitride (S ia N4) whiskers, and alumina (AI) whiskers.
□03) Whiskers, titanium boride (TUB) whiskers, titanium phosphide (TiP>whiskers, etc.) can be used.

Depending on the usage conditions, not only the ceramic whiskers described above but also metal whiskers and graphite whiskers may be used. The metal whiskers can be made of chromium, copper, iron, or nickel. Here, the silicon carbide-5- whisker has a tensile strength of about 1400 threads per 1111 m2. Also, the silicon nitride whisker has a tensile strength of about 1400 ta per 11I11. Alumina whiskers have a tensile strength of about 2100 per mm2.

Graphite whiskers have a tensile strength of about 1990 strands per 1 mm2, and iron whiskers have a tensile strength of about 1330 strands per 1 mm2.
The chrome whiskers have a tensile strength of approximately 910 sheets.

The whisker preferably has a diameter in the range of 0.1 to 1 μm. This is because the strength decreases slightly as the diameter of the whisker increases. The whisker length is preferably 10 to 200 microns. The whiskers may be generated by a vapor phase method, naturally grown from a solid, or by electrodeposition. For example, α-alumina whiskers may be extracted from a molten metal. Depending on the usage conditions, the whisker surface may be coated. A coating treatment can improve the wettability of the whiskers with the metal matrix.

Short fibers have theoretical strength or near theoretical strength -6- It is a fiber with lower strength than whisker, which has higher strength.

Short aHM is a fiber with a length of rim units, de 5 units, or m units. The length of the short mtrtt is usually longer than the whisker length, and is generally 0.5 to 5 mm. However, the length of the short fibers may be varied depending on the conditions of use of the FRM, and the length may be 1 l or more. In addition, short fibers have a length of several meters.
It is also possible to cut the fibers of

The short fibers may be either ceramic fibers or metal fibers. As short ceramic fibers, carbon fibers, silicon nitride fibers, alumina m fibers, silica alumina fibers, boron fibers, and potassium titanate IIi miscellaneous fibers can be used. The alumina fiber may have an α-alumina structure or a β-alumina structure. Depending on the conditions of use, the mm fibers may be glass fibers.

The surface of the short fibers may be coated depending on the conditions of use.

The fiber aggregate of the present invention is composed of a mixture of short fibers and whiskers. In this case, it is desirable that the whiskers and short fibers are dispersed randomly and uniformly. However, depending on the conditions of use, it may have directionality. The proportion occupied by fiber aggregates in FRM, that is,
The volume content of the mM aggregate is preferably about 30%. The reason for this is that the effects of fibers are more likely to appear. However, w
The volume content of miscellaneous aggregates is not limited to 30%,
Various changes can be made.

The proportion of short fibers in the fiber aggregate or the proportion of whiskers in the fiber aggregate varies depending on the conditions of use of the FRM. For example, when the short fibers are carbon fibers and the whiskers are silicon carbide whiskers, if you want to increase the strength, increase the proportion of silicon carbide sand whiskers, and if you want to suppress the price increase, increase the proportion of carbon 11iH.

When mixing short fibers and whiskers to form a fiber aggregate, either mechanical mixing means or chemical mixing means may be used. As a mechanical mixing means, short fibers and whiskers are mixed in a solvent and vigorously stirred. The stirring speed is set appropriately. As the solvent, water, alcohol, acetone, etc. can be used. As the stirring means, ordinary means can be used. For example, stirring using a mixer, rotary blade, rotor, stirring using ultrasonic vibration, etc. can be used.

When the length of short fibers is less than a few millimeters, it is preferable to perform mechanical mixing.

As a chemical mixing means, vapor phase method (Ch
chemical vapor deposition
Measures can be taken to generate and grow whiskers by n). For example, the short fibers provided in the reaction container are
800-90℃ while heated to about 80-1000℃
A raw material gas heated to 0° C. is introduced into the reaction vessel, and the raw material gas is heated and thermally decomposed, thereby generating and growing whiskers on the surface of the short fibers in a flocked or feather-like manner. Mixing of whiskers and short fibers is carried out. The reason why the heating temperature for the short #JAN was set to 980 to 1000°C is to selectively precipitate whiskers among various forms of precipitation.

When silicon carbide whiskers are grown on the surface of short fibers, a mixed gas of silicon tetrachloride (SIC14) and propane cc3H is used as the raw material gas. The mixing ratio is 4:
1 is good. Nitride-9- When growing silicon whiskers on the surface of short fibers,
Silicon tetrahydride (S i H8) and nitrogen (N-L) based gas are preferably used as the raw material gas. In addition, when growing titanium boride whiskers on the surface of short fibers, titanium chloride (TiC14), boron chloride (BC'I), and hydrogen (
It is preferable to use a mixed gas with H) as the raw material gas. In order to promote the generation of whiskers and to adjust the whisker diameter, it is preferable to attach a small amount of gold, silver, platinum, magnesium, chromium, etc. to the surface of the short fibers.

When titanium boride and short fibers are mixed, it is preferable to keep the temperature of the short fibers at 1050 to 1070 degrees and to avoid adhering gold, silver, platinum, palladium, rhodium, etc. to the surface of the short fibers.

When forming a fiber aggregate by the above-mentioned chemical mixing means, it is necessary to heat the raw material gas introduced into the reaction vessel for thermal decomposition or the like.

The raw material gas may be heated together with the reaction vessel using a heater provided outside the reaction vessel. Note that the raw material gas is preferably preheated to 80-10-0 to 900°C before being introduced into the reaction vessel.

According to the chemical mixing means described above, that is, the vapor phase method, it is possible to mix the short fibers and whiskers even when the short fibers are relatively long, or when the short U and strip are in the form of a cross, a mat, or a felt. Moreover, it is possible to suppress unevenness in the degree of mixing. Furthermore, since the vapor phase method coats precipitates other than whiskers, such as polycrystalline films, reactions with the matrix can be prevented. Alternatively, since whiskers grow in the shape of short #A flocks, there is an advantage that a fiber molded article with a low bulk density and low content can be produced.

In addition, in the case of chemical mixing means, that is, the gas phase method, it can be used not only for relatively long short fibers but also for relatively short short fibers of 50 to 500 μm.

The metal matrix in which the fiber aggregate is embedded can be changed in various ways depending on the type of fiber whisker used or the use of the FRM. For example, when yriIIiN is carbon fiber, the metal matrix is usually aluminum or an aluminum alloy. Aluminum alloy is J l5-ADC
l 2 is good. JIS-A-11-DCI 2 is an aluminum-silicon-copper alloy,
It is an alloy containing 3.3% copper and 11% silicon. Alternatively, an aluminum-silicon-copper-nickel-magnesium alloy may be used. Also, aluminum-silicon-magnesium alloy,
Alternatively, an aluminum-magnesium alloy may be used. Depending on the usage conditions, the metal 71 helix may be replaced with magnesium,
It can also be made of titanium, copper or an alloy thereof.

A conventional method can be used to embed the #HM aggregate in the metal matrix. In this case, a so-called liquid phase method is preferable. As the liquid phase method, it is desirable to use a molten metal forging method also called a high pressure casting method. Molten metal forging is a method that applies high pressure during the solidification process of the metal matrix. In the case of molten metal forging, the pressure applied is preferably around 500 lbs. per cm2, but depending on the case, it may be more or less than this. Incidentally, a vacuum infiltration method, a die casting method, or a diffusion bonding method may be used. Here, the vacuum infiltration method is a method in which the fiber aggregate is placed in a mold, the mold is evacuated, and the metal matrix is impregnated between the fibers.

-12 - The FRM of the present invention can be used, for example, in the vane of a vane-type compressor or the rotor of a supercharger.

[Effects of the Invention] As described above, the FRM of the present invention is a fiber-reinforced metal composite material in which a fiber aggregate is embedded in a metal matrix, and the fiber aggregate is composed of a mixture of short fibers and whiskers. It is characterized by the fact that Therefore, the disadvantages of the fiber-reinforced FRM can be compensated for by the whiskers while keeping the advantages of the fiber-reinforced FRM. In addition, short fibers can compensate for the disadvantages of whisker-reinforced FRM while taking advantage of its advantages. Therefore, compared to FRM reinforced with fiber alone or FRM reinforced with whisker alone, the industrial use of FRM can be expanded.

[Example] Figures 1 (A), (B), (C), and (D) are diagrams showing the manufacturing process when the FRM of the present invention is applied to a compressor vane. First, as shown in FIG. 1(A), a required amount of carbon fibers [1] as short fibers and silicon carbide whiskers 2 as rice-13 are weighed.

In this case, the carbon fiber is 5 mm, and the silicon carbide whisker 2 is 1 mm.
I made it 4m4. Then, this is charged into the solvent 4 in the container 3. Solvent 4 was water. In this state, as shown in FIG. 1(B), the mixture is stirred using rotary blades 5. The stirring speed was 10 times per second. Next, after removing the solvent 4, it was dried at 100 to 150° C. for 20 minutes and formed into a predetermined shape to obtain a fiber aggregate 6.

Next, with the fiber aggregate 6 set in the mold γ, the molten aluminum alloy 9 in the ladle 8 was poured into the mold 7. Molten aluminum alloy 9 is 1IIADC12
was used. Also, the temperature of the molten aluminum alloy 9 is 850°C.
And so.

Next, the molten aluminum alloy 9 in the mold 7 is heated to a pressure of 500
Molten metal forging was performed under pressure at kg/C1.

Thereafter, the molded product was taken out from the mold 7, subjected to post-treatment, and used as a compressor vane 1o.

FIGS. 2(A) and 2(B) are diagrams C showing the manufacturing process -14- when the FRM of the present invention is similarly applied to a compressor vane. In this example, the length is 50-300
Carbon fibers 11 with a diameter of 7 μ and a volume content of 5% were provided in the center of the reaction vessel 12. In this case, carbon fibers 11 are held within reaction vessel 12 by perforated plate 13 . still,
The perforated plate 13 is made of refractory material and has many holes with a diameter of about 1 mm. Then, by passing a high frequency current through a high frequency coil 14 provided outside the reaction vessel 12, the carbon fiber H11 is heated by induction. When a high frequency current is passed through the high frequency coil 14, an induced current is generated in the carbon fiber 11, thereby heating the carbon fiber [11] to about 1000°C. The frequency of the high frequency current is preferably 4.0 OK to 4M l-IZ. With the carbon lli fibers 11 heated in this manner, raw material gas preheated to around 870° C. is introduced into the reaction vessel 12 through the introduction pipe 15. In this case, a mixed gas of silicon tetrachloride (StCl, 1>) and propane (C31-13) was used as the raw material gas.The mixing ratio of silicon tetrachloride gas and propane gas was 4:1. Flow rate 3.0cc
/sec.

The reaction time was 20 minutes. As a result, carbon fiber H1-15
- Silicon carbide whiskers with a length of 50 to 200 μ and a diameter of 0.1 to μ are generated on the surface of 1, and these whiskers are shown in Figure 2 (B).
As shown in Figure 2, they grew in large numbers in the form of flocks or feathers. The raw material gas that has generated whiskers is discharged outward from the perforated plate 13 through the discharge pipe 1G.

Once the silicon carbide whiskers have grown on the surface of the carbon fibers 11 in this manner, the carbon fibers 11 are taken out from the reaction vessel 12 and used as a fiber aggregate 18.

in this way! Once the lH aggregate 18 was formed, the fiber aggregate 18 was impregnated with molten aluminum alloy by the hot melt manufacturing method in the same manner as in the previous embodiment, thereby producing a complex rib vane in the same manner as in the previous embodiment.

[Test Example] The strength characteristics of FRM were tested when the short fibers were carbon fibers and the whiskers were SIC whiskers. In this case, F.R.
The proportion of the fiber aggregate in M, that is, the volume content of the fiber aggregate was 30%.

Then, the proportion of carbon fiber and the proportion of SiC whiskers were varied with the volume content being 30%. Test-16- The test results are shown in Figures 3 to 5. Note that the volume of the test piece was 100 cm3. The fiber aggregate of the test piece was formed by a rubber press. Carbon fiber has a diameter of 7μ
, the length is 50-200μ.

Also, SiC whiskers have a diameter of 0.1 to 1 μm and a length of 50 μm.
~200μ. The metal matrix is JIs-A [)
012, with a depletion degree of 850°C and a pressure of 500 ka.
/ arm', a metal matrix was formed by a molten metal forging method.

As shown in Figure 3, FRM reinforced with carbon iam only
In this case, the bending strength was only about 30 kg/mm2.

However, when the proportion of SiC whiskers increases, the bending strength of Si
Increases in proportion to the increase in C whiskers, increasing carbon fiber by 40%
, the bending strength is 7 when the proportion of SIC whiskers is 60%.
It was about 0 ko/mm2. Therefore, addition of SiC whiskers is effective in increasing bending strength.

Furthermore, the coefficient of thermal expansion is 11 for FRM reinforced only with carbon fiber.
．． 7X1o-6, which remained almost unchanged with a slight increase even if the proportion of SIC whiskers was increased. From the results shown in FIG. 3, it can be seen that if the fiber-N East composite is constructed by mixing carbon I&LI strings and SiC whiskers, the bending strength can be increased arbitrarily without substantially changing the coefficient of thermal expansion.

In contrast, conventional FRM reinforced only with carbon fiber,
The percentage of FRM strengthened only with SIC whiskers includes the seventh
As shown in the figure, when the proportion of carbon fibers and SIC whiskers is increased in order to increase the bending strength, the coefficient of thermal expansion changes considerably, and the range of variation is large. For example, in the case of FRM reinforced with only SIC whiskers, when the content of SiC whiskers is 5%, the bending strength is 36 kmMm...2 and the coefficient of thermal expansion is 18.8X10-';
If the content of SiC whiskers is set to 30% in order to increase the temperature to kg/n+1, the coefficient of thermal expansion is as large as 11.6×10 −′ (decreased).

FRrVI reinforced only with carbon fiber as shown in Figure 4
So, the hardness is Rockwell hardness B steel, HRB79.
It is. On the other hand, when the proportion of SiC whiskers is increased, the hardness is proportional to the increase in SiC whiskers, and when the proportion of -18-scars is 60%, the hardness increases to HRB93. Therefore, when you want to increase the hardness of FRM, Si
It is better to increase the proportion of C whiskers.

On the other hand, in FRM strengthened only with SiC whiskers, the fourth
As shown in the figure, its hardness is 1 to 1RB102, which is very hard, and its wear resistance is excellent, but on the other hand, its seizure resistance is not very good. Therefore, if carbon fiber is mixed, the seizure resistance can be improved because carbon fiber has good sliding properties. On the other hand, an FRM reinforced only with carbon fibers has good enclosure properties and seizure resistance, but on the other hand, has a large amount of wear.

Therefore, if SiC whiskers are mixed in, the amount of wear can be reduced.

Further, as shown in FIG. 4, the specific gravity of FRM reinforced with only SiC whiskers is 2.8. However, when increasing the proportion of carbon uAN, carbon! The specific gravity decreases in proportion to the amount of miscellaneous increase. For example, 40% carbon fiber and 60% SiC whisker.
When the ratio is set to , the specific gravity decreases to 2.65. FIG. 8 shows the -19- hardness and specific gravity values of the FRM reinforced only with carbon fibers and the FRM reinforced only with SiC whiskers.

As shown in FIG. 5, the cost of SiC whiskers is approximately 1000 yen per sweetfish, but if carbon fiber is mixed with this, the cost will be reduced considerably.

Therefore, once the strength and hardness of the FRM is secured to a predetermined value using SiC whiskers, the price can be reduced by mixing carbon fiber.

FIG. 6 is a graph in which various characteristics of the FRM were investigated when the short #a fibers were made of alumina IJAm and the whiskers were SiC whiskers, unlike the test example described above. In this case, the proportion of the fiber aggregate in the FRM, that is, the volume content of the fiber aggregate was 30%. The percentage of alumina fiber and the percentage of SiC whiskers were varied with the volume content being 30%. Furthermore, the length of the alumina fiber is 5.
It is 0 to 500μ. The remaining conditions are the same as the previous test example.

The test results are shown in FIG. As shown in FIG. 6, the bending strength and hardness of the FRM increased by 112 as the number of SiC whiskers increased. However, the coefficient of thermal expansion hardly varied by -20-.

[Brief explanation of drawings]

FIG. 1 (A), (B), (C) and <D> are diagrams showing the manufacturing process of an FRM according to an embodiment of the present invention.
Figures (A> are side views with carbon fibers and SiC whiskers observed, Figure 1 (B) is a schematic sectional view showing the state in which stirring is being performed, and Figure 1 (C) is the state with the solvent removed. FIG. 1(D) is a side view of the fiber aggregate, and FIG.
Figure (E) is a perspective view of the compressor vane. FIGS. 2(A) and 2(B) are diagrams showing the manufacturing process of FRM according to another embodiment of the present invention. More specifically, FIG. Fig. 2 is a partially cutaway side view showing the step of introducing whiskers to generate whiskers. Fig. 2 is a side view of a fiber aggregate in which whiskers have been generated. Figs. This is a graph showing a test example, and the total volume content of FRM medium fibers is 30%. Figure 3 is a graph showing the characteristics of bending strength and coefficient of thermal expansion, and Figure 4 is a graph showing the characteristics of hardness and coefficient of thermal expansion. Figure 5 is a graph showing the characteristics of specific gravity, and Figure 5 is a graph showing the cost of fibers. Figure 6 is a graph showing other test examples of the product of the present invention, showing the characteristics of bending strength, hardness, and coefficient of thermal expansion. Fig. 7 is a graph showing the bending strength and thermal expansion coefficient of SiC whisker-reinforced FRMXC fiber reinforced FRM, which is a comparative example.
It is a graph showing the hardness and specific gravity of RM. In the figure, 1 and 11 are carbon fibers, 2 and 19 are SIC whiskers, 9 is a molten aluminum alloy, 1° is a vane, and 12
indicates a reaction vessel. Patent applicant Nippondenso Co., Ltd. agent Patent attorney Hirotoshi Okawa Patent attorney Shudo Fujitani Patent attorney Akio Maruyama = 22 − (n + Jj!!!, α Engineering H- 1Q Rodo Lg: N-10 procedural amendment writing method) 1981 4. D 26 F+ Commissioner of the Japan Patent Office Kazuo Wakasugi 2. Name of invention Fiber-reinforced metal composite material; 3. Supplement 1] - Relationship with the case of the person who did - Patent applicant 1-1 Showa-cho (426), Kariya City, Aichi Prefecture [1] Hondenso Co., Ltd. Representative Kengo 4, Agent Address: 450 Aichi Prefecture Name J11 City Nakamura Ward Name Station: 3T 113
No. 4 Kodama Pill (Telephone: 052-58-3-9720) 5. Date of amendment order: March 7, 1980 (shipped on March 27, 1982) 6. Name of the invention in the specification to be amended. column, column for detailed explanation of the claimed invention, and column for brief explanation of drawings 7゜Contents of amendment As shown in the attached sheet, the typeprint has been retyped in a more appealing and larger typeface. 8. List of documents (1) Amended specification 1 copy = 2-

Claims (1)

[Claims] (1) A fiber-reinforced metal composite material in which a laN aggregate is embedded in a metal matrix, characterized in that the fiber aggregate is composed of a mixture of short fibers and whiskers. Fiber-reinforced metal composite material. <2> The fiber according to claim 1, wherein the m-fiber aggregate is formed by chemical mixing means that heats a raw material gas introduced onto the surface of the short fiber to grow whiskers on the surface of the short fiber. Reinforced metal composite material. (3) The IT fiber-reinforced metal composite material according to claim 1, wherein the fiber aggregate is formed by stirring short fibers and whiskers in a solvent using mechanical mixing means. <4> The fiber-reinforced gold-metallic composite material according to claim 1, wherein the short m string is made of one or more of carbon fibers, silicon carbide fibers, alumina fibers, and silica-alumina fibers. (5) The fiber-reinforced metal composite material according to claim 1, wherein the short fibers have a length of 0.5 to 5 mm. (6) Whiskers include silicon carbide (SiC) whiskers, silicon nitride (SiqN+) whiskers, and alumina (△1□O
The fiber-reinforced metal composite material according to claim 1, which is one or more of the following: whiskers of titanium boride (TiB), whiskers of titanium phosphide (TiP), and whiskers of titanium phosphide (TiP). (7) The fiber-reinforced metal composite material according to claim 1, wherein the volume content of the 4[aggregate] is 30%. (8) The fiber-reinforced metal composite 8-size according to claim 1, wherein the metal matrix is impregnated into the fiber aggregate by a molten metal casting method. (c) The fiber-reinforced metal composite material according to claim 1, wherein the metal matrix is aluminum or an aluminum alloy.