JP3467495B2 - Method for producing metal-based gradient composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION The present invention relates to an Al alloy, a Mg alloy, and the like.
Which metal, ceramicsFiber or whiskerStrengthen
Metal-based composite material used as a material, especially inclined
The present invention relates to a method for producing a metal-based gradient composite material having characteristics. [0002] 2. Description of the Related Art Metal matrix composites reinforced with ceramics
Powder metallurgy method, molten metal method, compocas
Pressure impregnation method, which has excellent industrial productivity
(High pressure solidification method, squeeze cast method)
I have. In this pressure impregnation method, a ceramic compact (preform
Reform) and impregnate it with molten metal
Is the law. Further, in this method, the manufactured composite material
In addition, strength, Young's modulus, coefficient of thermal expansion, thermal conductivity, wear resistance, etc.
It is known how to manufacture composite materials with various mechanical properties.
Have been. For example, a ceramic compact
Molded so that the volume ratio changes sequentially,
There is a method of infiltrating a molten metal which is
2-197375). [0003] SUMMARY OF THE INVENTION Composites with tilt characteristics
When manufacturing materials, methods such as the powder metallurgy method
Due to technical difficulty and low productivity, pre-
A pressure impregnation method is used to infiltrate the molten metal into the foam.
You. However, there are the following questions about this pressure impregnation method.
There is a point. For example, as shown in FIG.
Rate is Vf_A<Vf_B<Vf_C<Vf _DDifferent
Reforms A, B, C and D were separately molded
And stack them. And as shown in FIG.
It is housed in the mold 50, and after pouring the molten metal 51 from above,
Pressure is applied by the punch 52, and the molten metal is contained in the preform.
It has a different volume fraction.
That many preforms must be made,
A gap between the preforms A, B, C, and D that are simultaneously stacked
Precise work steps are required to eliminate these.
On the other hand, the composite material thus manufactured is shown in FIG.
Thus, the change in the volume ratio is discontinuous. Therefore, use this
The composite material manufactured in
Material characteristics become discontinuous and gradually inclined performance is required
It is not preferable as a gradient composite material to be used. The present invention
It was made in view of the above circumstances,
It is an object of the present invention to provide a metal-based gradient composite material. [0004] According to the present invention, there is provided the present invention.
IsCeramic fiber or ceramic whiskerStep
In the method of impregnating the molten metal with pressure in the reform,
Preform volume by controlling pressing speed, temperature and pressure
The characteristics of the composite material can be changed by changing the ratio
The control data to make
Ask forThis is a method for producing a metal-based gradient composite material. [0005] The inventors of the present invention have proposed the use of pressure impregnation for gold.
During the production process of the matrix composite material, the pressure of the molten metal
Focusing on the point that the preform causes compression deformation, many
Perform experiments and calculations to determine the deformation mechanism of this preform.
A theoretical formula that can elucidate the mechanism was derived. And pre-
Melt pressure applied to the preform is the cause of deformation of the preform
That this pressure is applied to the preform and metal
Infiltration of molten metal into preform due to its characteristics
Compounded by speed, preform and metal temperature,
Clarified that the conditions will be determined. Therefore, this reason
By using the theoretical formula, the pressure
For continuous gradient composites by immersion, preforms
It can be manufactured while controlling to an arbitrary volume ratio
Became. 1) Derivation of theoretical formula General ceramic fiber (including whisker) pre
When molten aluminum infiltrates the foam, the Reynolds number is small.
For that reason, Darcy's law can be applied. Ma
In addition, the molten aluminum is used as an incompressible fluid,
Force and viscous drag are dominant,
Considering inertia to be negligible, Darcy's law and continuity
It is assumed that the following expression holds. Where Darcy's formula is
It is expressed by the following equation. [0007] (Equation 2) Applying this to the surface added to the preform
The pressure Ps and the molten metal tip position Xf were derived. [0009] (Equation 3)Further, the solid fraction F is expressed by the following equation.
You. [0011] (Equation 4) As described above, the preform has a surface pressure P
s determines the degree of compressive deformation, that is, the slope of the volume fraction.
Can be 2) Implementation procedure First, a preform consisting of one or more materials
Is formed by a wet or dry method. This preform
Is preferably uniform inside. Next, as shown in FIG.
Thus, the preform 21 is pre-heated at room temperature or
It is set in the heated mold 22. And melt the metal from the top
Hot water 23 is poured, and the pressurized cylinder 25 is actuated.
And pressurized by a punch 24. In this case, the mold temperature
By the temperature control means 28 and the pressing speed of the punch 24
Is controlled by the speed control means 29, and the pressing force is controlled by the pressure control means.
30 and the data set based on the theoretical formula
Is performed while controlling each. By this
Therefore, as a tilt aspect of the composite material to be produced, the volume ratio is
Constant, volume ratio changes in the middle, first
The volume ratio changes from the beginning, the volume ratio changes from the beginning
But does not change in the latter half, the volume ratio changes at the end
Graded composites with various volume fractions
You. [0014] EXAMPLE A silicon carbide (SiC) whisker was 80 × 8
Preform molded to 0%, height 40mm and volume ratio 15%
And pure aluminum (99.99%) by pressure impregnation
To produce a graded composite material. Silicon carbide whiskers
Table 1 shows the characteristics of pure aluminum when melted at 800 ° C.
Table 2 shows the characteristics of um. [0015] [Table 1] [0016] [Table 2] The preform preheated to 750 ° C.
Set in a 80x80mm mold heated to 0 ° C,
Pour pure aluminum dissolved at 800 ° C and pressurize
Was performed. Speed at pressurization: 10, 20, 40 mm /
Set to S. As a result, the height of the preform after compounding
Were compressed to 33, 29, and 23 mm, respectively. Further, the volume ratio of the inside was measured.
As a result, as shown in FIG.
Yes, from a certain position, the volume ratio gradually increases
Is molded. And this inclination state depends on the pressing speed.
The inclination angle increases as the pressing speed increases.
ing. Further, a silicon carbide whisker is set in a mold.
And the pressure and volume ratio when pressing with a punch are also measured.
Was. Then, the pressure change obtained by the above-mentioned theoretical formula and this measurement
By using the fixed value, the preform inclination amount is calculated.
The results were in agreement with the measured results. From the above results, pressurization
By controlling the speed, the amount of inclination of the composite material can be changed.
Wear. In addition, the manufacturing conditions for any continuous gradient composite are:
It is also possible to calculate using the above theoretical formula. [0020] According to the present invention, gold is impregnated using a pressure impregnation method.
The following effects can be obtained when manufacturing a metal-graded composite material.
Can be 1) Use multiple materials for the preform
Use different types or combine preforms with different volume ratios
No need. 2) Therefore, the preform molding process can be greatly reduced
Therefore, it is possible to manufacture a low-cost gradient composite material. 3) Slope that changes continuously without any discontinuity in the volume ratio
A composite material is obtained. 4) By arbitrarily selecting the compounding conditions, one type of
Many types of graded composite materials can be manufactured from renovation
You.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual explanatory view of an apparatus used for a manufacturing method of the present invention. FIG. 2 is a graph showing a change in a volume ratio of a preform corresponding to a pressing speed in an example according to the present invention. FIG. 3 is a diagram illustrating an embodiment of a preform according to a conventional method. FIG. 4 is a view for explaining a manufacturing method using the preform of FIG. 3; FIG. 5 is a diagram illustrating a discontinuous change in volume ratio of a preform according to a conventional method. [Description of Signs] 21 Preform 22 Mold 23 Melt 24 Punch 25 Pressurizing cylinder 28 Temperature control means 29 Speed control means 30 Pressure control means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C22C 47/00-49/14

Claims (1)

(57) [Claims] [Claim 1] Ceramic fiber or ceramic screen
A method for the molten metal into a preform of Scar pressurized圧含immersed, pressurization rate and the temperature control for the a specific slope ratio characteristics of a composite material while changing the volume fraction of the pressurized preform to control the pressure The data is expressed by the following formula,
A method for producing a metal-based gradient composite material, characterized in that: (Equation 1)