JPS60154862A - Ceramics-metal composite body and its production - Google Patents

Abstract

PURPOSE:To control the internal stress to be generated by insert casting by using a precipitation hardening alloy as a metal and controlling the content and form of the precipitate of the alloy thereby controlling the mechanical strength thereof to prescribed strength. CONSTITUTION:A ceramic material having a prescribed shape is inserted into a casting mold then the melt of a precipitation hardening alloy is poured into the mold in the stage of producing a ceramics-metal composite body consisting of a ceramic layer and a metallic layer. After such melt is cooled to solidify, the alloy is subjected to a heat treatment or the cooling rate of the melt is controlled by which the content or form of the precipitate of the above-mentioned alloy is controlled and the mechanical strength thereof is controlled. The control of the internal stress to be generated in the ceramics-metal composite body is thus made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a ceramic material comprising a ceramic layer and a metal layer.
This invention relates to a metal composite and its manufacturing method.

Ceramics are prized as structural members in various fields due to their excellent corrosion resistance, durability, heat resistance, and heat insulation properties. Recently, ceramic-metal composites in which a metal layer is bonded to a ceramic layer have been attracting attention in order to make ceramics easier to process and incorporate into equipment, and to improve effective strength. . Such ceramic-metal composites are usually manufactured by the so-called casting method, which involves inserting a ceramic material in a predetermined shape into a mold, and then injecting and solidifying a molten metal.

It is being put to practical use in engine parts such as sub-combustion chambers, molten metal processing such as molten metal pumps, and metal processing.

In the above applications, repeated thermal stress and external stress are applied to the ceramic-metal composite, and the composite is one in which cracks, delamination, etc. occur due to such thermal stress and external stress. Must not be.

As mentioned above, the ceramic-metal composite is usually manufactured by the casting method, but during cooling and assimilation by the casting method, stress is applied to both the ceramic and the metal due to their different coefficients of thermal expansion. Ceramics usually have a smaller coefficient of thermal expansion than metals, so when a metal layer is coated around the outer periphery of a cylindrical ceramic material, compressive stress is generated in the ceramic material as internal stress, and the metal layer is coated with compressive stress. generates tensile stress. Ceramics usually have low tensile strength and high compressive strength, and when the above compressive stress is applied to ceramics, the effective strength improves, which is an advantage of ceramic-metal composites as described above. If the stress or tensile stress exceeds the compressive strength or tensile strength of the ceramic or metal, fatal defects such as deformation, cracks, and delamination will occur in the ceramic-metal composite. Conversely, if the compressive stress applied to the ceramic material during cooling and solidification by the casting method is too small, in applications where pressure is applied from the inside, such as in cylinders, the stress during use may cause tensile stress on the ceramic layer. Stress will be applied and breakage will occur. It is desirable that the stress applied to the ceramic material and metal layer constituting the ceramic-metal composite be appropriate for the strength of the ceramic material and metal layer. In other words, it is necessary to adjust the internal stress exerted on the ceramic material and the metal layer depending on the use of the ceramic-metal composite. However, if such selection is based only on ceramics or metal materials, problems will arise in terms of usage conditions, manufacturing methods, economic efficiency, etc. Therefore, if it were possible to adjust the internal stress that occurs when cooling and solidifying the same material, ceramics or metal, by the casting method, the above problems would be solved and the practicality of ceramic-metal composites would be history. It will probably improve.

The present invention focuses on the above conventional problems and adjusts the internal stress generated in the ceramic-metal composite by adjusting the mechanical properties of the metal to a predetermined value using the same metal material. The purpose is to
The main idea is to use a precipitation hardening alloy as the metal, and adjust the mechanical strength of the alloy to a predetermined value by adjusting the precipitate content and/or morphology of the alloy.

The invention will be explained in detail below.

The strength of the precipitation hardening alloy used in the present invention varies greatly depending on the precipitate content and/or the form of the precipitates. Mar6
M, 200. lN100. All known precipitation hardening alloys such as Ni-based alloys such as Incone and 1L'7130 are included. In part 1-, the precipitate content and t/d of the precipitation hardening type alloy are determined.
or precipitate form)! l changes depending on the heat treatment after casting or the speed of cold lamination during casting, and the strength is adjusted accordingly.

Examples of ceramics used in the present invention include alumina.

Zirconia, zircon, chromium oxide, spinel.

All known ceramics such as silicon nitride and silicon carbide are included.

The above-mentioned casting method is generally applied to produce the ceramic-metal composite of the present invention.

In other words, in the casting method, if desired, a binder is added to the ceramic powder, which is molded into a predetermined shape using a rubber press method, etc., and then fired. Then, the molten M'hI of the precipitation hardened Paris alloy is poured into a mold and cooled and solidified. For example, the expansion coefficient for silicon nitride and silicon carbide is 3 to 4X10=/'
C, alumina is 8X 10-6/'C, zirconia is 11 Xl0-6/'C, incone/L'7
13C, 8US630 etc. (7) 10~20XlO'-
/'Small compared to CvC. Therefore, in the cold casting process of the casting method, stress is applied to the ceramic material and the metal layer constituting the ceramic-metal composite due to the difference in thermal expansion coefficient between the ceramic and the metal, as described above.

However, since the yield strength of metal is low at high temperatures, even if the above-mentioned stress is applied, the metal layer follows the stress and is plastically deformed 17, thereby relaxing the stress in a short time. That is, the stress relaxation time of metals at high temperatures is short. As the cooling progresses, the metal layer, which has a high yield strength, follows the stress and no longer undergoes plastic deformation.

As a result, the stress relaxation time is long, and residual stress is exerted on the metal layer and furthermore on the ceramic material. The residual stress with 1. This is mainly due to the difference in thermal expansion coefficient between ceramics and metals.

In other words, when such stress is applied to the ceramic material and metal layer, the yield strength of the metal increases and the plastic deformation of the metal can follow the stress. This is the case when the temperature drops below the operating temperature. If we can adjust the yield strength of metals, we can adjust the temperature at which stress is applied, and ceramics
Defects such as denaturation of metal composites and delamination of one layer of electrical equipment can be prevented. Therefore, in the present invention, the above precipitation hardening alloy is used as the metal constituting the ceramic-metal composite. As mentioned above, in precipitation hardening alloys, the content and/or morphology of precipitates can be changed by heat treatment after casting or rapid cooling during casting, and the yield strength can be adjusted to a large extent.

For example, the height HB of Fe-based superalloy A286 varies depending on the solution temperature as shown in FIG. 1. Figure 1 is a graph with stiffness HB on the vertical axis and aging time (hr) on the horizontal axis, which shows that as the aging temperature increases, the hardness decreases and the 1 yield strength decreases. It will be done.

Examples will be described below to further specifically explain the present invention.

Zirconium irregularity O-3m on the surface of a cylindrical partially stabilized zirconium molding with an exception diameter of 30B1, an inner diameter of 25 mm, and a height of 30 mm.
It was thermally sprayed to a thickness of m to form a ceramic material.

ν1 by wrapping the ceramic material and using the lost wax method.
A mold is made, and the mold is heated to 200°C, and then a melt of Inconel 713c (1420'C) is injected to a thickness of 3mm Inconel/L'7 only on the outer periphery of the ceramic material. ] Cast the 3C layer. After injecting the melt, it is cooled to room temperature and then heat treated as shown in Table 1. As the heat treatment temperature increases, the shape of the precipitates in the Incone/'7]3C layer, whose main precipitated phase is the r' phase with NiBAg as its basic form, gradually becomes coarser from a fine precipitated state and becomes more plastic. As shown in Table 1, the stress in the circumferential direction of t(27 Umix material becomes smaller).

Table 1 In Table 1, the circumferential stress of the ceramic material was measured using a strain gauge.

According to Table 1, when the cylindrical ceramic-metal composite of this example is used for applications where pressure is applied to the inside, it is necessary to counteract the internal pressure. It is desirable that the circumferential stress exerted on the ceramic material is large, in which case heat treatment is not required, and if no internal pressure is applied, it is desirable that the stress be small;
For example, heat treatment at 900°C for 4 hours is appropriate.

Performance Test The performance of the ceramic-metal composite produced according to the above example was tested.

(a) A fatigue test was conducted by sealing both ends of the cylindrical ceramic metal composite and filling the inside with oil, applying a hydraulic pressure of 2t/(7)2 for 2 minutes, and then removing it for 3 minutes. Ta. The number of cycles until the ceramics constituting the Ceramic Nut Metal Composite breaks down in the fatigue test is determined by the second
Shown in the table.

Table 2 (b) A cycle was performed in which the above ceramic-metal composite was placed in a furnace maintained at 400°C for 5 minutes and then allowed to cool for 5 minutes. Table 3 shows the number of cycles in 1 at which the ceramics constituting the ceramic-metal composite were destroyed in the above thermal cycle test.

Table 3 Table 2 shows that when the heat treatment temperature is high, the stress in the circumferential direction exerted on the ceramic material constituting the seven-metal composite becomes smaller, and the ceramic breaks down in a short time due to internal pressure. Table 3 shows that, conversely, when the heat treatment temperature is low, the stress in the circumferential direction that is applied to the ceramic material constituting the metal composite becomes large, and the ceramic can be destroyed in a short period of time due to this stress. be recognized.

[Brief explanation of drawings]

Figure 2 is a graph plotting the relationship between the hardness H-B of A286 and the aging time (hr) after hardening treatment for each solution treatment temperature. In the figure, Q-Q Aging treatment temperature 816°C・-・77
60°C ()-() // 704°C ○-○ 〃649°C Patent applicant Daido Steel Co., Ltd. Nippon Spark Plug Co., Ltd.

Claims (2)

[Claims] (1) In a ceramic-metal composite consisting of a ceramic layer and a metal layer, a precipitation hardening alloy is used as the metal, and the alloy is castable by controlling the mechanical strength by adjusting the precipitate content and/or the form of the precipitate. A ceramic-metal composite characterized in that the internal stress generated by the wrapping is adjusted to a predetermined value. (2) Step 1: Inserting a ceramic material of a predetermined shape into the mold; Step 2: Injecting a molten precipitation hardening alloy into the mold; 2: The molten material is cooled and solidified, and then heat treatment is performed, or the molten material is Step 3: Adjusting the mechanical strength of the alloy by controlling the cooling rate of the alloy and/or the morphology of the precipitates, thereby adjusting the internal stress generated by casting to a predetermined value. Method for manufacturing a ceramic-metal composite consisting of the above steps 1.2.3