US20200199714A1

US20200199714A1 - Metal-ceramic composite material and method for forming the same

Info

Publication number: US20200199714A1
Application number: US16/231,686
Authority: US
Inventors: Chi-San Chen; Chih-Chao Yang; Chih-Jung Weng; Yu-Hsien Chou; Li-Shing CHOU; Heng-Yi Tsai
Original assignee: Industrial Technology Research Institute ITRI
Current assignee: Industrial Technology Research Institute ITRI
Priority date: 2018-12-24
Filing date: 2018-12-24
Publication date: 2020-06-25
Also published as: TWI727266B; TW202024347A

Abstract

A metal-ceramic composite material and a method for forming the same are provided. The metal-ceramic composite material includes a metal body, a plurality of metal oxide nanoparticles and a plurality of ceramic particles. The metal body includes a metal material having a first surface energy. The metal oxide nanoparticles and the ceramic particles are dispersed in the metal body. The ceramic particles have a second surface energy that is higher than the first surface energy.

Description

TECHNICAL FIELD

The present disclosure relates to a metal-ceramic composite material and a method for forming a metal-ceramic composite material.

BACKGROUND

Due to fuel prices going up and environmental issues such as energy conservation and carbon reduction, Europe launched a project called the Clean Sky JTI (Joint Technology Initiative) in 2008 to improve the technological performance of aircraft and air transportation in Europe. The project aims to define the developmental direction of the aviation industry in the future, including reduction of fuel consumption and reduction of noise, such as reducing carbon emissions by 50% for next-generation aircraft, reducing carbon monoxide emissions by 80%, and reducing engine noise by 50%, and these specific targets are expected to be achieved by 2020. In this regard, lightweight components can be used to reduce weight and improve flight efficiency. The development of lightweight materials and structural designs has recently become the main focus of this effort.
In addition to the development of lightweight components in aerospace technology, the automobile industry has gradually turned to adopting lightweight components in engine systems. For example, lightweight components are expected to be utilized in an impeller with a complicated shape in an automobile turbocharger system in order to improve the operating efficiency.
Lightweight components used in either aerospace technology or the automobile industry are required to have excellent mechanical properties, such as tensile strength, hardness, rigidity, etc.
Therefore, with the increasing needs described above, researchers have been working on developments and improvements of lightweight components having the desired mechanical properties.

SUMMARY

The present disclosure relates to a metal-ceramic composite material and a method for forming a metal-ceramic composite material. In the embodiments, in the metal-ceramic composite material, the metal oxide nanoparticles dispersed in the metal body enhance the compatibility between the metal material having a relatively low surface energy and the ceramic particles having a relatively high surface energy. This way, the ceramic particles can be dispersed in the metal body more uniformly. The hardness of the metal-ceramic composite material can effectively be improved, and the mechanical strength and rigidity of the metal-ceramic composite material can be increased.
According to an embodiment of the present disclosure, a metal-ceramic composite material is provided. The metal-ceramic composite material includes a metal body, a plurality of metal oxide nanoparticles, and a plurality of ceramic particles. The metal body includes a metal material having a first surface energy. The metal oxide nanoparticles and the ceramic particles are dispersed in the metal body. The ceramic particles have a second surface energy that is higher than the first surface energy.
According to another embodiment of the present disclosure, a method for forming a metal-ceramic composite material is provided. The method includes the following steps: mixing a metal starting material and a plurality of ceramic particles to form a mixture, wherein the metal starting material comprises a metal powder and a metal oxide interlayer formed on the surface of the metal powder, the metal powder comprises a metal material having a first surface energy, and the ceramic particles have a second surface energy that is higher than the first surface energy; performing a pretreatment on the mixture to form a pretreated mixture, wherein the ceramic particles are attached to the metal oxide interlayer in the pretreated mixture; and performing a fabrication process on the pretreated mixture to form the metal-ceramic composite material.
To further simplify and clarify the foregoing contents and other objects, characteristics, and merits of the present disclosure, a detailed description is given in the following embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a schematic drawing of a metal-ceramic composite material according to an embodiment of the present disclosure;

FIG. 1B is an enlarged view of the region 1B in FIG. 1A;

FIG. 2 shows a schematic drawing of a metal starting material according to an embodiment of the present disclosure;

FIG. 3 shows a schematic drawing of a pretreated mixture according to an embodiment of the present disclosure;

FIG. 4A to FIG. 4C show imaging contrast in SEM pictures of metal-ceramic composite materials according to some embodiments of the present disclosure;

FIG. 5 shows an X-ray diffraction pattern of a metal-ceramic composite material according to an embodiment of the present disclosure; and

FIG. 6 shows a TEM picture of a metal-ceramic composite material according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

In the embodiments of the present disclosure, in the metal-ceramic composite material, the metal oxide nanoparticles dispersed in the metal body enhance the compatibility between the metal material having a relatively low surface energy and the ceramic particles having a relatively high surface energy, so that the ceramic particles can be dispersed in the metal body more uniformly. In this manner, the hardness of the metal-ceramic composite material can effectively be improved, and the mechanical strength and rigidity of the metal-ceramic composite material can be increased. Details of embodiments of the present disclosure are described hereinafter with accompanying drawings. Specific structures and compositions disclosed in the embodiments are used as examples and for explaining the disclosure only and are not to be construed as limitations. A person having ordinary skill in the art may modify or change corresponding structures and compositions of the embodiments according to actual application.
Unless explicitly indicated by the description, as used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that when such as the term “comprises” and/or “comprising,” is used in this specification, it specifies the presence of described features, steps, operations, elements, and/or components, but does not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.
Throughout this specification, the term “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the phrases “in one embodiment” or “in an embodiment” in various contexts throughout this specification do not necessarily all refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be appreciated that the following figures are not drawn to scale; rather, these figures are merely illustrations.
FIG. 1A shows a schematic drawing of a metal-ceramic composite material 10 according to an embodiment of the present disclosure, and FIG. 1B is an enlarged view of the region 1B in FIG. 1A. As shown in FIGS. 1A-1B, the metal-ceramic composite material 10 includes a metal body 100, a plurality of metal oxide nanoparticles 200, and a plurality of ceramic particles 300. The metal body 100 includes a metal material having a first surface energy. The metal oxide nanoparticles 200 and the ceramic particles 300 are dispersed in the metal body 100. The ceramic particles 300 have a second surface energy that is higher than the first surface energy.
According to the embodiments of the present disclosure, the metal oxide nanoparticles 300 dispersed in the metal body 100 enhance the compatibility between the metal material having a relatively low surface energy and the ceramic particles 300 having a relatively high surface energy, so that the ceramic particles 300 can be dispersed in the metal body 100 more uniformly. This effectively improves the hardness of the metal-ceramic composite material 10 and increases the mechanical strength and rigidity of the metal-ceramic composite material 10.
In some embodiments, the metal material having the first surface energy may include metal or an alloy. For example, in some embodiments, the metal material having the first surface energy may include aluminum (Al), copper (Cu), iron (Fe), silicon (Si), cobalt (Co), lead (Pb), an alloy of any of the above metals, or any combination of the above.
In the embodiments, the ceramic particles 300 may include silicon carbide (SiC), tungsten carbide (WC), or a combination thereof. In some embodiments, as shown in FIGS. 1A-1B, the ceramic particles 300 may have a particle size D1 of about 0.5 μm to about 20 In some embodiments, as shown in FIGS. 1A-1B, the ceramic particles 300 may have a particle size D1 of about 1 μm to about 10 In some embodiments, as shown in FIGS. 1A-1B, the ceramic particles 300 may have a particle size D1 of about 2 μm to about 5 μm.
According to some embodiments of the present disclosure, the particle size D1 of the ceramic particles 300 is relatively small, such as equal to or less than 10 μm. As such, there can be a relatively large number of the ceramic particles 300 dispersed in a unit volume of the metal body 100, resulting in a better dispersion of the ceramic particles 300 within the microstructure of the metal body 100. The metal-ceramic composite material 10 can be strengthened more effectively and uniformly by the ceramic particles 300.
In the embodiments, the metal oxide nanoparticles 200 may include aluminum oxide, copper oxide, iron oxide, silicon oxide, cobalt oxide, lead oxide, or any combination of the above. In some embodiments, as shown in FIG. 1B, the metal oxide nanoparticles 200 may have a particle size D2 of about 3 nm to about 50 nm.
In some embodiments, the metal oxide nanoparticles 200 may be formed of a native oxide of the metal material having the first surface energy. For example, in some embodiments, the metal material may be aluminum, and the metal oxide nanoparticles 200 may be aluminum oxide nanoparticles.
In some embodiments, the first surface energy may be less than 1.5 J/m², and the second surface energy may be higher than 2 J/m². Accordingly, in some embodiments, the difference between the first surface energy and the second surface energy is higher than 0.5 J/m².
In some embodiments, the first surface energy may be less than 1.0 J/m², and the second surface energy may be higher than 2.5 J/m². Accordingly, in some embodiments, the difference between the first surface energy and the second surface energy is higher than 1.5 J/m².
In some embodiments, the metal material of the metal body 100 may be aluminum or an aluminum alloy having a surface energy of about 0.84 J/m². In some embodiments, the metal material of the metal body 100 may be silicon having a surface energy of about 1.24 J/m².
In some embodiments, the ceramic particles 300 may be silicon carbide particles having a surface energy of about 3.2 J/m². In some embodiments, the ceramic particles 300 may be tungsten carbide particles having a surface energy of about 1.6 J/m²to 8.7 J/m².
In some embodiments, the metal oxide nanoparticles 200 have a third surface energy, and a difference between the second surface energy and the third surface energy may be less than 1 J/m². In some other embodiments, the difference between the second surface energy and the third surface energy may be less than 0.5 J/m².
According to some embodiments of the present disclosure, the relatively small difference between the surface energies of the metal oxide nanoparticles 200 and the ceramic particles 300 is advantageous to the interaction and bonding between the metal oxide nanoparticles 200 and the ceramic particles 300, and the interaction and bonding make it easier for the ceramic particles 300 to be dispersed within the metal body 100 with the help from the metal oxide nanoparticles 200. As a result, according to some embodiments of the present disclosure, the smaller the difference between the second surface energy and the third surface energy is, the better enhancement of the compatibility between the metal material and the ceramic particles 300 can be provided from the metal oxide nanoparticles 200.
In some embodiments, the metal oxide nanoparticles 200 may be aluminum oxide nanoparticles having a surface energy of about 2.0 J/m²to 4.0 J/m².
In some embodiments, as shown in FIGS. 1A-1B, the metal-ceramic composite material 10 has grains 10A and grain boundaries 10B, and the metal oxide nanoparticles 200 may be formed within the grain boundaries 10B. In some embodiments, more specifically, a portion of the metal oxide nanoparticles 200 may be formed within the grain boundaries 10B, while another portion of the metal oxide nanoparticles 200 may be bonded to the ceramic particles 300 dispersed in the grains 10A.
In some embodiments, the metal oxide nanoparticles 200 may be present in the amount of less than about 2 vol. % of the metal-ceramic composite material 10. In some embodiments, the metal oxide nanoparticles 200 may be present in the amount of less than about 1 vol. % of the metal-ceramic composite material 10. In some embodiments, the metal oxide nanoparticles 200 may be present in the amount of about 0.1 vol. % to 1 vol. % of the metal-ceramic composite material 10.
According to some embodiments of the present disclosure, if the metal oxide nanoparticles 200 are present in the amount of above 2 vol. % of the metal-ceramic composite material 10, the whole structure of the metal-ceramic composite material 10 may be too brittle, due to there being too many metal oxide nanoparticles 300. This may result in reduced mechanical strength of the metal-ceramic composite material 10. Thus, the metal oxide nanoparticles 200 present in the amount of about 0.1 vol. % to 1 vol. % of the metal-ceramic composite material 10 can improve the compatibility between materials of the metal body 100 and the ceramic particles 300 without deteriorating the mechanical properties of the metal-ceramic composite material 10.
In some embodiments, the metal oxide nanoparticles 300 and the metal material having the first surface energy in total may be present in the amount of about 70-97 vol. % of the metal-ceramic composite material 10.
In some embodiments, the ceramic particles 300 may be present in the amount of about 3-30 vol. % of the metal-ceramic composite material 10.
According to some embodiments of the present disclosure, if the amount of the ceramic particles 300 is less than 3 vol. % of the metal-ceramic composite material 10, the as-formed metal-ceramic composite material 10 may have reduced mechanical strength and rigidity. If the amount of the ceramic particles 300 exceeds 30 vol. % of the metal-ceramic composite material 10, despite largely increasing the rigidity, the as-formed metal-ceramic composite material 10 may have reduced tensile strength. As such, the ceramic particles 300 present in the amount of 3-30 vol. % of the metal-ceramic composite material 10 can provide excellent mechanical strength and rigidity as well as increased tensile strength for the metal-ceramic composite material 10.
According to the embodiments of the present disclosure, a method for forming a metal-ceramic composite material 10 is provided.
According to the embodiments of the present disclosure, the method for forming the metal-ceramic composite material 10 includes mixing a metal starting material 20 and a plurality of ceramic particles 300 to form a mixture, and performing a pretreatment on the mixture to form a pretreated mixture 30.
FIG. 2 shows a schematic drawing of a metal starting material 20 according to an embodiment of the present disclosure, and FIG. 3 shows a schematic drawing of a pretreated mixture 30 according to an embodiment of the present disclosure. The elements in the present embodiment sharing similar or the same labels with those in the previous embodiment are similar or the same elements, and the description of which is omitted.
In the embodiments, as shown in FIG. 2, the metal starting material 20 includes a metal powder 220 and a metal oxide interlayer 210 formed on the surface 220A of the metal powder 220, and the metal powder 220 includes a metal material having a first surface energy. In the embodiments, the second surface energy of the ceramic particles 300 is higher than the first surface energy of the metal material of the metal powder 220. The details of the metal material having the first surface energy and the ceramic particles 300 having the second surface energy are as described above and not repeated here.
In the embodiments, as shown in FIG. 3, after performing the pretreatment, the ceramic particles 300 are attached to the metal oxide interlayer 210 in the pretreated mixture 30.
Currently, a reinforcing phase material is usually mixed with a metal material by stirring at elevated temperatures to form a reinforcing metal melt for forming a reinforced metal material. However, the large difference between the surface energies of the reinforcing phase material and the metal material leads to particle aggregations formed in the melt and poor dispersion of the reinforcing phase material. Even with high-speed stirring, only the reinforcing phase material with a large particle size may be dispersed within the melt, and this method also suffers from problems of high-speed stirring introducing a large amount of oxides formed on the surface of the melt into the reinforcing metal melt and undesirably increasing the viscosity of the reinforcing metal melt. The increased viscosity and oxygen content are disadvantageous to the following fabrication process as well as the mechanical properties of the as-formed reinforced metal material.
According to the embodiments of the present disclosure, the metal oxide interlayer 210 is formed on the surface 220A of the metal powder 220, so that the ceramic particles 300 can easily be in contact with the metal oxide interlayer 210 of the metal starting material 20 in the mixture; then, after the pretreatment is performed, the ceramic particles 300 are driven to be attached, e.g. through chemical bonding, to the metal oxide interlayer 210 and/or the fragments of the metal oxide interlayer 210 of the metal starting material 20 in the pretreated mixture 30, since the metal powders 220 are nicely dispersed in the pretreated mixture 30, the ceramic particles 300 along with the metal oxide interlayers 210 and/or the fragments of the metal oxide interlayer 210 on the metal powders 220 are thereby nicely dispersed within the pretreated mixture 30. As a result, the metal oxide interlayer 210 enhances the compatibility between the metal material having a relatively low surface energy and the ceramic particles 300 having a relatively high surface energy. As such, with the design of the mixture as well as the pretreatment step according to the embodiments of the present disclosure, the pretreated mixture 30, in which the ceramic particles 300 are uniformly dispersed within the metal material, is provided with good mechanical strength and rigidity and is ready for following fabrication processes.
In some embodiments, as shown in FIG. 2, the metal oxide interlayer 210 may be formed of a native oxide of the metal powder 220. For example, in some embodiments, the metal oxide interlayer 210 may be formed of an oxide of the metal material having the first surface energy. The examples of the material of the metal oxide interlayer 210 are basically the same as those described above for the metal oxide nanoparticles 200, and the details are not repeated here.
In some embodiments, as shown in FIG. 3, the ceramic particles 300 may have a particle size D1 of about 0.5 μm to about 20 about 1 μm to about 10 or about 2 μm to about 5 μm.
In some embodiments, the metal oxide interlayer 210 may have a third surface energy, and a difference between the second surface energy and the third surface energy may be less than 1 J/m².
According to some embodiments of the present disclosure, the difference between the second surface energy of the ceramic particles 300 and the third surface energy of the metal oxide interlayer 210 is relatively small, e.g. less than 1 J/m², and the surface 220A of the metal powder 220 is covered by the metal oxide interlayer 210, allowing the metal starting material 20 and the ceramic particles 300 to have similar surface energies, preventing particle aggregation upon mixing and/or stirring, and providing a more uniform dispersion of the metal starting material 20 and the ceramic particles 300. This allows the introduction of the ceramic particles 300 with a relatively small particle size D1, which results in a better dispersion of the ceramic particles 300 within the microstructure of the metal material.
In some embodiments, as shown in FIG. 2, the metal oxide interlayer 210 may have a thickness T1 of about 5 nm to about 7 nm.
In some embodiments, as shown in FIG. 2, the metal powder 220 may have a particle size D3 of about 10 μm to about 300 In some embodiments, as shown in FIG. 2, the metal powder 220 may have a particle size D3 of about 200 μm to about 300 μm.
According to some embodiments of the present disclosure, the thickness T1 of the metal oxide interlayer 210 is relatively thin, limiting the volume of the metal oxide involved in the pretreatment and formed in the pretreated mixture 30, so as not to generate any unwanted phases in the pretreated mixture 30. Accordingly, the mechanical properties of the pretreated mixture 30 as well as the as-formed metal-ceramic composite material 10 are not affected by an unwanted phase. Furthermore, the relatively thin thickness T1 of the metal oxide interlayer 210 limits the amount of metal oxides present in the metal-ceramic composite material 10, which prevents the whole structure of the metal-ceramic composite material 10 from being too brittle—a condition caused by too much metal oxide. Thereby, the mechanical properties of the metal-ceramic composite material 10 are not affected.
In addition, according to some embodiments of the present disclosure, the particle size D1 of the ceramic particles 300 is relatively small, e.g. equal to or less than 10 μm. The particle size D3 of the metal powder 220 is relatively large, e.g. about 200 μm to about 300 More ceramic particles 300 can be attached to the metal oxide interlayer 210 formed on the metal powder 220, and thus a more uniform dispersion of the ceramic particles 300 is achieved.
In some embodiments, the metal starting material 20 may be present in the amount of about 70-97 vol. % of the mixture.
In some embodiments, the ceramic particles 300 may be present in the amount of about 3-30 vol. % of the mixture.
In some embodiments, the pretreatment may include heating, pressurizing, or a combination thereof, but the present disclosure is not limited thereto.
In some embodiments, performing the pretreatment may include heating the mixture at about 400° C. to about 500° C. for about 2 hours to 4 hours. In some embodiments, the pretreatment may be performed under a pressure of about 200-500 Pa.
According to some embodiments of the present disclosure, if the pretreatment is performed at a temperature of lower than 400° C., the pretreatment reaction may not be fully completed, and there may be less attachment and/or the chemical bonding formed between the ceramic particles 300 and the metal oxide interlayer 210 (and/or the fragments of the metal oxide interlayer 210); if the pretreatment is performed at a temperature of above 500° C., the metal material would melt quickly, resulting in less attachment and/or the chemical bonding formed between the ceramic particles 300 and the metal oxide interlayer 210 (and/or the fragments of the metal oxide interlayer 210). Therefore, according to some embodiments of the present disclosure, performing the pretreatment by heating the mixture at about 400° C. to about 500° C. provides more attachment and/or the chemical bonding formed between the ceramic particles 300 and the metal oxide interlayer 210 (and/or the fragments of the metal oxide interlayer 210), and thus the resulting dispersion of the ceramic particles 300 is further enhanced.
Next, according to the embodiments of the present disclosure, the method for forming the metal-ceramic composite material 10 further includes performing a fabrication process on the pretreated mixture 30 to form the metal-ceramic composite material 10.
In some embodiments, the fabrication process may include a gas atomization process, a pouring casting process, a continuous casting process, a die casting process, a vacuum casting process, a low-pressure casting process, an additive manufacturing process, or any combination thereof, but the present disclosure is not limited thereto.
According to some embodiments of the present disclosure, the metal-ceramic composite material 10 may be a bulk material or a powder material. In some embodiments, for example, a gas atomization process can be performed on the pretreated mixture 30 to form the metal-ceramic composite material 10 as a powder material, and a 3D object may be further formed from the powder material by an additive manufacturing process. In some embodiments, a casting process can be performed on the pretreated mixture 30 to form the metal-ceramic composite material 10 as a bulk material.
Further explanation is provided with the following examples. Compositions of metal-ceramic composite materials and measurements of properties of the metal-ceramic composite materials are listed for showing the properties of the metal-ceramic composite materials according to the embodiments of the disclosure. However, the following examples are for purposes of describing particular embodiments only, and are not intended to be limiting.

EXAMPLES

Preparation of a Pretreated Mixture

[Pretreated Mixture 1]

95 vol. % of an aluminum starting material (an aluminum oxide layer having a thickness of about 5-7 nm covered on each aluminum powder having a particle size of about 1-150 μm, and 5 vol. % of silicon carbide (SiC) particles having a particle size of about 2-5 μm are mixed, then the mixture is heated at 450° C. for 3 hours under a pressure of about 100 Pa and then cooled to room temperature, and then the pretreated mixture 1 of aluminum-silicon carbide composite material is obtained.

[Pretreated Mixtures 2-3]

The preparation of pretreated mixtures 2 and 3 is similar to that of pretreated mixture 1, with the only difference being the volume ratios of the aluminum starting material to the silicon carbide particles. The pretreated mixture 2 includes 92 vol. % of aluminum starting material and 8 vol. % of silicon carbide (SiC) particles, and the pretreated mixture 3 includes 89 vol. % of aluminum starting material and 11 vol. % of silicon carbide (SiC) particles.

Examples 1-3

The pretreated mixture is heated to a temperature above the melting point of the aluminum powder to form an aluminum-silicon carbide composite melt, and then aluminum-silicon carbide composite particles are formed from the aluminum-silicon carbide composite melt by gas atomization. The morphology and composition of the as-formed particles are characterized by SEM.
FIG. 4A to FIG. 4C show imaging contrast in SEM pictures of metal-ceramic composite materials according to some embodiments of the present disclosure, and FIG. 5 shows an X-ray diffraction pattern of a metal-ceramic composite material according to an embodiment of the present disclosure. More specifically, FIG. 4A shows the silicon carbide coverage of an aluminum-silicon carbide composite particle of Example 1, FIG. 4B shows the silicon carbide coverage of an aluminum-silicon carbide composite particle of Example 2, FIG. 4C shows the silicon carbide coverage of an aluminum-silicon carbide composite particle of Example 3, and FIG. 5 shows the X-ray diffraction pattern of the aluminum-silicon carbide composite particles of Example 3.
As shown in FIG. 4A, the silicon carbide coverage is about 4.1% to 5.2%, which is almost the same as the volume ratio of the silicon carbide addition (5 vol. %). As shown in FIG. 4B, the silicon carbide coverage is about 8% to 8.8%, which is almost the same as the volume ratio of the silicon carbide addition (8 vol. %). As shown in FIG. 4C, the silicon carbide coverage is about 11%, which is basically the same as the volume ratio of the silicon carbide addition (11 vol. %).
As shown in FIG. 5, the XRD pattern shows that the aluminum-silicon carbide composite particles of Example 3 do not form any unwanted crystalline phase except for the expected crystalline phases of aluminum, silicon, and silicon carbide.
An additive manufacturing process is further performed on the aluminum-silicon carbide composite particles of Example 2 to form a 3D object. The mechanical properties and morphology of the 3D object formed from the aluminum-silicon carbide composite particles of Example 2 are characterized, the results are shown in table 1 and FIG. 6, and mechanical properties of some commercial available comparative examples are also shown in table 1 for comparison.
FIG. 6 shows a TEM picture of a metal-ceramic composite material according to an embodiment of the present disclosure. More specifically, FIG. 6 shows the TEM picture of a 3D object formed from the aluminum-silicon carbide composite particles of Example 2 by an additive manufacturing process.
As shown in FIG. 6, the microstructure of the aluminum-silicon carbide composite 3D object has grains and grain boundaries, and the bright spots within the grain boundaries, proven by TEM diffraction patterns (not shown herein), are aluminum oxide nanoparticles.

TABLE 1

3D object from	Comparative	Comparative
Example 2	example 1	example 2

Material	Aluminum-silicon	EN AW-6082 T6	A359 aluminum
	carbide composite	aluminum alloy	alloy mixed with
	particles of Example 2		20 wt % of SiC
Fabrication process	Additive	Forging	O'Fallon casting
	manufacturing
Yield strength	390	370	303
(MPa)
Ultimate tensile	445	400	359
strength (MPa)
Elongation rate (%)	3	15	<1
Hardness	HRB 85 (162 HBW)	—	—
Young's modulus	~85	70	99
(GPa)

As shown in table 1, the object of Comparative example 1 does not contain any silicon carbide material. Despite its high yield strength and high ultimate tensile strength, the low Young's Modulus of 70 GPa indicates that its rigidity is too low.
In addition, while the object of Comparative example 2 contains 20 wt % of silicon carbide, the object of Comparative example 2 is neither formed of a metal-ceramic composite material according to the embodiments of the present disclosure, nor formed by a method according to the embodiments of the present disclosure. As indicated in table 1, the object of Comparative example 2 has high rigidity, but the elongation rate is too low, which may cause the object to break suddenly without warning when a very low tensile force is applied, raising safety concerns.
As shown in table 1, the 3D object formed from Example 2 is provided with excellent yield strength, ultimate tensile strength, hardness, and rigidity as well as a proper elongation rate, so that the 3D object has excellent mechanical properties with minimum safety concerns.
While the disclosure has been described by way of example and in terms of the exemplary embodiments, it should be understood that the disclosure is not limited thereto. On the contrary, it will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.

Claims

What is claimed is:

1. A metal-ceramic composite material, comprising:

a metal body comprising a metal material having a first surface energy;

a plurality of metal oxide nanoparticles dispersed in the metal body; and

a plurality of ceramic particles dispersed in the metal body, wherein the ceramic particles have a second surface energy higher than the first surface energy.

2. The metal-ceramic composite material as claimed in claim 1, wherein the first surface energy is less than 1.5 J/m², and the second surface energy is higher than 2 J/m².

3. The metal-ceramic composite material as claimed in claim 1, wherein the metal oxide nanoparticles have a third surface energy, and a difference between the second surface energy and the third surface energy is less than 1 J/m².

4. The metal-ceramic composite material as claimed in claim 1, wherein the ceramic particles have a particle size of 0.5 μm to 20 μm.

5. The metal-ceramic composite material as claimed in claim 1, wherein the metal oxide nanoparticles have a particle size of 3 nm to 50 nm.

6. The metal-ceramic composite material as claimed in claim 1, wherein the metal oxide nanoparticles are present in an amount of less than 1 vol. % of the metal-ceramic composite material.

7. The metal-ceramic composite material as claimed in claim 1, wherein the metal oxide nanoparticles are formed of a native oxide of the metal material having the first surface energy.

8. The metal-ceramic composite material as claimed in claim 7, wherein the metal-ceramic composite material has grains and grain boundaries, and the metal oxide nanoparticles are formed within the grain boundaries.

9. The metal-ceramic composite material as claimed in claim 1, wherein the metal oxide nanoparticles and the metal material having the first surface energy in total are present in an amount of 70-97 vol. % of the metal-ceramic composite material.

10. The metal-ceramic composite material as claimed in claim 1, wherein the ceramic particles are present in an amount of 3-30 vol. % of the metal-ceramic composite material.

11. The metal-ceramic composite material as claimed in claim 1, wherein the metal material having the first surface energy comprises aluminum, copper, iron, silicon, cobalt, lead, or a combination thereof, and the ceramic particles comprise silicon carbide, tungsten carbide, or a combination thereof.

12. A method for forming a metal-ceramic composite material, comprising:

mixing a metal starting material and a plurality of ceramic particles to form a mixture, wherein the metal starting material comprises a metal powder and a metal oxide interlayer formed on the surface of the metal powder, the metal powder comprises a metal material having a first surface energy, and the ceramic particles have a second surface energy higher than the first surface energy;

performing a pretreatment on the mixture to form a pretreated mixture, wherein the ceramic particles are attached to the metal oxide interlayer in the pretreated mixture; and

performing a fabrication process on the pretreated mixture to form the metal-ceramic composite material.

13. The method for forming the metal-ceramic composite material as claimed in claim 12, wherein the metal oxide interlayer is formed of a native oxide of the metal powder, and the metal oxide interlayer has a thickness of 5 nm to 7 nm.

14. The method for forming the metal-ceramic composite material as claimed in claim 12, wherein the pretreatment comprises heating, pressurizing, or a combination thereof.

15. The method for forming the metal-ceramic composite material as claimed in claim 12, wherein performing the pretreatment comprises heating the mixture at 400° C. to 500° C. for 2 hours to 4 hours.

16. The method for forming the metal-ceramic composite material as claimed in claim 12, wherein the fabrication process comprises a gas atomization process, a pouring casting process, a continuous casting process, a die casting process, a vacuum casting process, a low-pressure casting process, an additive manufacturing process, or any combination thereof.

17. The method for forming the metal-ceramic composite material as claimed in claim 12, wherein the first surface energy is less than 1.5 J/m², and the second surface energy is higher than 2 J/m².

18. The method for forming the metal-ceramic composite material as claimed in claim 12, wherein the ceramic particles have a particle size of 0.5 μm to 20 μm.

19. The method for forming the metal-ceramic composite material as claimed in claim 12, wherein the metal starting material is present in an amount of 70-97 vol. % of the mixture.

20. The method for forming the metal-ceramic composite material as claimed in claim 12, wherein the ceramic particles are present in an amount of 3-30 vol. % of the mixture.