JPH02217246A - Preparation of inclined functional material - Google Patents

Abstract

PURPOSE:To prepare a large inclined functional material having a complicated shape by providing a plurality of materials wherein a mixed composition of fine crystal particle ceramics and a fine crystal particle metal is inclined and superposing said materials in the order of inclination and subsequently pressing the superposed materials in a superplasticity developing temp. region to integrally bond and mold the same. CONSTITUTION:Partial stabilized zirconia containing 3mol.% of yttria developing superplasticity at predetermined temp. in a solid solution form and alumina are mixed and a mixture inclined in its compositional ration is used as the intermediate layer with respect to said zirconia and alumina or said mixture is superposed in a multilayered fashion to be interposed between zirconia and alumina and bonded at superplastic temp. under pressure to prepare a material equipped with functions possessed by both materials. By this method, an integrated inclined functional material wherein the functions of both materials are generally inclined from one side to the other side and mutually different functions are provided on both sides is obtained. Therefore, by utilizing superplastic bonding, bonding and molding can be performed simultaneously and a large inclined functional material having a complicated shape can be prepared.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to functionally graded materials (Functionally G
radienLM Material).

b. Prior Art In recent years, several space flights have been carried out by spacecraft such as the space shuttle. Since such flying vehicles are exposed to light heat and high pressure during flight, materials that have both heat resistance and mechanical strength are required. In reality, it seems to be a combination of homogeneous materials with specific functions, such as silica tiles, which are heat-resistant materials, and metal materials, which have high mechanical strength.

The present invention differs from such a homogeneous material in that it has two different functions, that is, one material has different Il.
This invention relates to so-called functionally graded materials, which have functional properties in a graded state.

Conventional techniques related to such functionally graded materials include manufacturing methods such as vapor phase methods (PVD, CVD), particle array methods, plasma spray deposition methods, and self-heating reaction methods. In addition, as recently developed technology for manufacturing methods of functionally graded materials, Japanese Patent Application No. 60-297042 and Japanese Patent Application No. 187370-1982
There is a number.

C0 Problems to be Solved by the Invention Among the above methods, the vapor phase method has an extremely slow film formation rate of about 1 coat/h, and the PVD method (physical method) is particularly difficult to synthesize films using simple materials. It will be limited to only.

In addition, in the particle arrangement method, it is difficult to fill and arrange the raw material powder by changing the composition arbitrarily, and it is necessary to develop easily sinterable ceramic powder and new sintering technology.

The plasma spray deposition method has the disadvantage that it is difficult to spray different materials exactly at the same location, and that variations in the composition of the formed layer are unavoidable.

Further, in the self-heating reaction method, for example, as shown in FIG. 3, the raw material powder is placed in a stepwise manner in the apparatus a, c, d.

After being filled as shown in e.g., it is ignited at point p and synthesized under pressure while causing a self-heating reaction.With this method, it is not possible to manufacture dense, complex, or large-sized items.

The present invention replaces the prior art as described above by utilizing superplastic bonding to perform bonding and forming at the same time.
It is an object of the present invention to provide a method for manufacturing a functionally graded material that can be manufactured even in complex shapes.

d. Means for Solving the Problems In accordance with the above-mentioned object, the present invention provides a plurality of materials in which the mixed compositions of fine-crystalline ceramics and fine-crystalline metals are graded, and after layering these materials in the graded order, The above-mentioned problem was solved by integrally joining and molding by applying pressure in the temperature range where superplasticity occurs.

The present invention will be explained in detail below.

The present invention uses a material having a fine grain two-phase mixed structure consisting of a ceramic having a grain size of about 1 m or less, or a metal having a grain size of about 10μ or less.

Then, by setting materials in which these compositions are graded continuously or discontinuously, using these as an intermediate layer, or layering them in the order of grade, and then joining them by applying pressure at superplastic temperature, It is possible to obtain a functionally graded material with strength equivalent to that of wood.

That is, a material that exhibits superplasticity at a predetermined temperature, for example, partially stabilized zirconia containing 3 mol x solid solution of ittria, and alumina is mixed, and the composition ratio is graded, as an intermediate layer between the zirconia and alumina.
Alternatively, multiple layers may be stacked and bonded under pressure at superplastic temperatures to produce a material that has the functions of both materials.

As a result, the functions of the material are gradually graded from one side to the other, resulting in an integrated functionally graded material having different functions on both sides.

e. Example As shown in FIG. 1, superplastic materials A to F are stacked in the order shown. Here A: 3solχY803 addition Zr0x B: Zr0t 80wtX, ^
j! gos 20wLX.

C: at Zr
8 wealth 60wtXt ^j! gos 40wt
X.

D: Zr0m 40wtX,
Affixes 6Qwtχ,E i'
ZrO* 20wtχ, ^l t's 80wt
X, F: consists of the following compositions: ^l *Os.

Note that materials A, B, C, D, and E are manufactured by sintering using hot isostatic pressing (HIP) at 1500° C. for 1 hour.

Material F was sintered at 1300° C. for 1 hour under normal pressure. All of these are superplastic materials that have particle sizes of 1 mm or less and exhibit elongation of 100% or more at high temperatures.

The mutual contact surfaces of these materials A to F were ground with a diamond wheel to a surface roughness of approximately Rmax2#-, stacked in layers in the order shown in Figure 1, and heated under bonding conditions of approximately 1500°C and 12.5 MPa. , a single piece of material was obtained by applying pressure. The resulting material had a bending strength of approximately 50/Peng.

FIG. 2 shows another example, in which a large number of superplastic materials having the above composition formed into a shape as shown in FIG. A one-piece product with the shape shown was changed.

f. Effects of the Invention According to the method for manufacturing a functionally graded material according to the present invention, the intermediate layer is made of a ceramic having a fine grained two-phase mixed structure or a material made of a metal whose composition is continuously or discontinuously graded. These are formed into layers and superplastically bonded.

Therefore, according to the present invention, by using superplastic joining, joining and forming can be performed simultaneously, and large-sized, ? 111
One shape of functionally graded material can be produced. Also, manufacturing costs are relatively low.

Furthermore, superplastic bonding allows the bonded interface to have the same strength as the base material, so it can also be used as a structural component.

Therefore, according to the present invention, the mechanical field that requires heat resistance, wear resistance, and corrosion resistance, the nuclear field that requires radiation resistance,
It can be widely used in electronics and optoelectronics fields that require electro-optical properties, medical fields that require biocompatibility, etc.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining one embodiment of the method for producing a functionally graded material according to the present invention, FIGS. 2(a) and (b) are diagrams for explaining another embodiment, and FIG. It is an explanatory diagram showing an example. Patent applicant Suzuki Motor Co., Ltd. (and 2 others) (b)

Claims (1)

[Claims] A plurality of materials are prepared in which the mixed compositions of fine-crystalline ceramics and fine-crystalline metals are graded, and after these are layered in the order of graded composition, they are bonded and formed into one piece by applying pressure in the temperature range where superplasticity occurs. A method for producing a functionally graded material.