JPS61127836A - Manufacture of potassium titanate fiber reinforced metal material - Google Patents

Abstract

PURPOSE:To manufacture preformed compact having high fiber content, by dispersing a specified quantity of inorganic binder into reinforcing material contg. potassium titanate, pressing and heating them in mold to solidify inorganic binder. CONSTITUTION:Aqueous soln. of inorganic binder (sodium silicate, etc.) is coated on potassium titanate fibers, so that binder weight becomes 1-5wt% against fiber weight. Said fibers 1 are fed in a preforming mold 2, and pressed by an upper punch 3 at a prescribed pressure. Next, said fibers are heated by a heater 4 provided surrounding the mold 2 to solidifying temp. of binder while being pressed, to vaporize water and solidify the binder. By this way, preform contg. about 50vol% fiber is obtd. The preform is heated in mold, to heat, press, permeate metal material to be matrix, thereby, reinforced metal material having smooth surface free from cracks and breaks is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a composite metal material containing reinforcing materials such as fibers and whiskers in a matrix metal.

[Conventional technology]

As a type of composite material, fiber reinforced metal materials (FRM) are known, in which fibers that develop high strength and high elasticity are used as reinforcing materials, and metals such as aluminum or alloys are used as a matrix. Various methods for producing metal materials have been proposed in the past.

One of the methods for manufacturing these conventional fiber-reinforced metal materials includes filling a casting mold with fiber reinforcement, and then introducing further molten matrix metal into the casting mold by means of a plunger element that engages the casting mold. A molten metal forging method is known in which molten matrix metal is solidified while being pressurized in a casting mold.

In this molten metal forging method, in order to give desired performance to products made of composite materials, the elongated material must be shaped into a predetermined shape during casting.
It is necessary to composite the reinforcing material and the matrix metal while maintaining the density and orientation.

For this reason, methods are known in which a fiber preform is produced by press-molding reinforcing fibers in advance, or by mixing the reinforcing fibers with a solvent such as water, followed by precipitation or filtration.

[Problem that the invention seeks to solve]

In order to manufacture the preform by pressure molding to make it a fiber-reinforced metal material with a high fiber content, in the case of whiskers represented by silicon carbide (SiC) and silicon nitride (S i 3N4), the aspect ratio Since the ratio is close to 100, the fibers are strongly intertwined with each other and can maintain their shape if pressure molded. However, the above-mentioned fibers are expensive and are not suitable for use in inexpensive fiber-reinforced materials. On the other hand, potassium titanate fiber is known as a cheap fiber, but when trying to obtain a preform of potassium titanate fiber by pressure molding, the aspect ratio is as small as about 30, so it is difficult to obtain a desired shape. However, due to the springback of the fibers, countless small cracks and layered cracks occur, and the fiber-reinforced metal material obtained by impregnating these with aluminum as a matrix metal has the following properties as shown in Figure 5. Problems such as chips, layered cracks, and continuous areas with low fiber density as shown in FIG. 6 remain as defects.

[Means for solving problems]

Therefore, in order to solve the above-mentioned problems, the present invention provides a method for producing a fiber-reinforced metal material containing potassium titanate fibers as a reinforcing material, in which the reinforcing material contains potassium titanate fibers in an amount of 1 to 5 wt% based on the reinforcing material. A method is adopted in which a preform that becomes a fiber-reinforced gold mud precursor is produced by dispersing an inorganic binder and heating it to the binder solidification temperature while pressurizing and holding it in a mold.

[Effect]

In the method according to the present invention, potassium titanate fibers to which 1 to 5 wt% of an inorganic binder is added to the fibers are solidified by heating and pressurizing them in a predetermined mold, so that despite having a small aspect ratio, The action of the inorganic binder effectively bonds the fibers together, making it possible to effectively prevent the aforementioned springback after the pressure is released.

[Example] Examples of the present invention will be described below with reference to the drawings. Sodium silicate (water glass) was selected as an inorganic binder for potassium titanate fibers, and the binder weight (excluding water) was 5% of the fiber weight. A solution diluted with water was applied by spraying or the like.

If the total weight of the solution to the fibers is less than 10%, it will be difficult to uniformly apply a small amount of solution to the fibers with a large bulk density, and if it exceeds 30%, there will be too much water, which will cause pressure molding. The solution is squeezed out from the mold clearance, making it difficult to obtain the desired defect-free preform.

Next, a required amount of potassium titanate fibers coated with a predetermined amount of binder are put into a preform molding die 2 shown in FIG. 1, and pressed by an upper bunch 3.

The pressing force varies depending on the desired fiber content, but for example, when manufacturing a fiber content of 3Qvo1%, the pressing force is 10
It is 0 kg/cm2. Next, while applying pressure, a heater 4 installed around the mold 2 is used to solidify the binder (2
00-300°C) to evaporate water and solidify the binder. The time required for solidification depends on the shape of the molded preform,
It varies depending on the binder type and concentration, but usually 15 to 30
It's a minute. By this method, the fiber content is 50 vol.
It is possible to manufacture preforms with a high content rate of up to 100% with high productivity.

Next, the preform obtained in this way was heated to about 450°C.
After the preform has been sufficiently preheated, the molten aluminum is heated to 00 to 850°C.
A potassium titanate fiber-reinforced metal material can be produced by impregnating the potassium titanate (99.9%) at 500 kg/cm 2 or more under pressure and then cooling and solidifying it in a mold.

In the method according to the present invention, preforms are produced by varying the amount of binder added to potassium titanate fibers from 1.3, 5, and 7.10%, and 99.9% is added so that the fiber content is 3Qvol-%. Table 1 shows the results of measuring the strength characteristics of the fiber-reinforced metal material obtained by impregnating aluminum with a three-point bending test. In addition, a product manufactured using lithium silicate as an inorganic binder in exactly the same manner as in the case of sodium silicate is also described. Moreover, FIG. 2 is a graph of this.

Table 1 As is clear from Table 1 and Figure 2, the amount of binder is 5w.
If the binder exceeds t%, the bending strength will begin to decrease rapidly and the object of the present invention will not be achieved sufficiently, regardless of whether the binder is sodium silicate or lithium silicate. Furthermore, if the amount of binder is less than 1 wt%, defects similar to those in the case where no binder is used will occur, and the effects of the present invention cannot be obtained.

FIG. 3 shows a preform obtained by carrying out the method according to the present invention with the addition of 1 wt% sodium silicate, and FIG. 4 shows a preform obtained by adding 1 wt% of sodium silicate, and FIG. This figure shows a potassium titanate fiber-reinforced aluminum material impregnated and produced by the km method. As is clear from a comparison with FIGS. 5 and 6, it is clear that when the present invention is implemented, chips and cracks caused by defects in the preform can be solved.

In addition to those shown in the first embodiment, the inorganic binder that can be used in the present invention may be calcium silicate, colloidal silica, etc., or a mixture thereof.

Further, the fibers used as the reinforcing material may be hybrid fibers of potassium titanate fibers and other fibers (silicon carbide, silicon nitride whiskers, short carbon fibers, etc.). Furthermore, the metal used as the matrix may be aluminum (99.9%), all aluminum alloys, magnesium, magnesium alloys, and other metals that can be used in ordinary molten metal forging methods.

In addition, in order to produce fiber-reinforced metal with a fiber content of 20VO1% or less using the pressure molding method, a preform is produced by uniformly mixing the fibers with metal powder that will serve as a matrix in advance. By applying the invention, it is possible to manufacture preforms of combinations of powder and fibers, which have different shapes and are prone to defects and density variations, uniformly and without cracking, and with a low fiber content. Preforms can be manufactured by a highly productive pressure molding method without using a precipitation method. In addition, since the molten metal remains firmly solidified when impregnated under pressure, the shape of the preform does not deform, which tends to occur in preforms produced by the precipitation method.

〔Effect of the invention〕

As described above, in the present invention, 1 to 5 wt% of the reinforcing material is added to the reinforcing material containing potassium titanate fibers.
By adding an inorganic binder and molding the preform, it is possible to eliminate the cracks and pot-shaped cracks that occur in the preform due to fiber spring puncture when no inorganic binder is used. The strength of fiber-reinforced metal obtained by impregnating metal with molten metal forging can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an example of the present invention, Fig. 2 is a characteristic diagram showing the bending strength when the amount of binder added is changed by the method according to the present invention, and Fig. 3 is a characteristic diagram showing the bending strength according to the method according to the present invention. A photograph showing the surface condition of the preform manufactured by the method disclosed in the Examples, FIG. 4 is a photograph showing the surface condition of the potassium titanate fiber-reinforced aluminum manufactured from the above preform, and FIGS. , is a photograph showing the surface condition of potassium titanate fiber-reinforced aluminum obtained by molding a preform without using a binder and impregnating it with aluminum. 1... Potassium titanate fiber in which binder is dispersed,
2... Preform mold, 3... Upper punch, 4
...heater.

Claims (3)

[Claims] (1) In a method for producing a fiber-reinforced metal material obtained by impregnating a reinforcing material containing potassium titanate fibers as at least one component with a metallic material serving as a matrix under heat and pressure, the reinforcing material containing potassium titanate fibers is inorganic. The binder is dispersed in the reinforcing material in an amount of 1 to 5 wt%, and this is heated to the inorganic binder solidification temperature while being pressurized in a mold to produce a fiber preform that becomes a fiber reinforced metal precursor. A method for producing a potassium titanate fiber-reinforced metal material, characterized in that: (2) The potassium titanate fiber-reinforced metal material according to claim 1, wherein the reinforcing material containing the potassium titanate fibers is a reinforcing material mixed with the matrix metal powder. Production method. (3) The method for producing a potassium titanate fiber-reinforced metal material according to claim 1, wherein the inorganic binder is sodium silicate, lithium silicate, calcium silicate, or colloidal silica.