WO2010055957A1

WO2010055957A1 - Composite damping metal sheet and method for producing same

Info

Publication number: WO2010055957A1
Application number: PCT/JP2009/069597
Authority: WO
Inventors: 金武直幸; 小橋眞; 谷澤元治; 木下恭一; 山名啓太; 原田正則; 磯野邦隆
Original assignee: 株式会社豊田自動織機
Priority date: 2008-11-14
Filing date: 2009-11-12
Publication date: 2010-05-20
Also published as: JP2010117024A

Abstract

Disclosed is a composite damping metal sheet comprising a metal sheet which is composed of an Fe-Al-Mn-Cr alloy or the like, and a metal foam layer which is composed of foamed aluminum or the like and arranged on the metal sheet. The metal foam layer is partially joined to the surface of the metal sheet. The composite damping metal sheet can be produced by melting a powder mixture of a metal powder and a foaming assistant powder, which generates a gas when decomposed by heating, and foaming the foaming assistant powder, on the surface of a metal sheet.

Description

Composite damping metal plate and manufacturing method thereof

The present invention relates to a composite vibration-damping metal plate comprising a metal plate and a metal foam.

In recent years, the influence of vibration and noise from vehicles such as automobiles, factories and construction sites on the living environment has been increasing. In addition, vibration and noise affect the life of parts, the operational accuracy of machines operating on the site, and the like, and are problematic in terms of maintaining functions. As one of countermeasures against vibration and noise, materials having a property of attenuating vibration energy are being developed. For example, materials such as rubber and plastic used as so-called vibration damping materials have a very high damping capacity. However, these materials are inferior to metal materials in terms of heat resistance, chemical resistance and mechanical strength. Therefore, a damping alloy having improved damping properties by improving the metal structure is useful. In addition, composite vibration damping materials made by combining different materials as described in Patent Documents 1 to 3 below have been developed.
Japanese Patent Laid-Open No. 5-124141 JP-A-1-258945 JP-A-4-278343

Patent Document 1 discloses a vibration damping material obtained by laminating a film-like foam-containing pressure-sensitive adhesive in which air bubbles are contained in acrylic rubber and sandwiched between two steel plates. Patent Document 2 and Patent Document 3 disclose a damping metal plate having a porous layer formed by sintering metal powder between two metal plates. Since this damping metal plate has a large specific surface area due to the presence of a plurality of pores, it has high energy absorption capability and exhibits damping properties.

By combining a metal material and rubber as in Patent Document 1, mechanical strength is improved as compared with the case of using only rubber, but use at high temperature is difficult. Therefore, in Patent Document 2 and Patent Document 3, a vibration-damping metal plate is configured using a porous layer made of metal instead of rubber. Such a vibration-damping metal plate can also be used at high temperatures. However, since the porous layer is made of a sintered body obtained by sintering metal powder, the mechanical strength is reduced when the porosity is increased in order to improve the vibration damping property. Further, the porosity of the sintered body is limited, and a sintered body having a high porosity has a problem in terms of strength and manufacturing.
In view of the above problems, an object of the present invention is to provide a composite vibration-damping metal plate that exhibits high vibration damping properties and excellent mechanical strength, and a method for manufacturing the same.
The composite vibration-damping metal plate of the present invention is a composite vibration-damping metal plate having a metal plate and a metal foam layer laminated on the metal plate, wherein the metal foam layer is partially on the surface of the metal plate. It is characterized by being joined.
The “metal foam layer” is formed by melting a mixed powder of a metal powder and a foaming assistant powder that decomposes by heating to generate gas and foaming the foaming assistant powder on the surface of the metal plate. Therefore, it is different from a porous layer made of a sintered body obtained by heating metal powder at a temperature lower than the melting point of the metal.
Further, the method for producing a composite vibration-damping metal plate of the present invention is a method for producing a composite vibration-damping metal plate having a metal plate and a metal foam layer laminated on the metal plate,
A preparation step of preparing a mixed powder of a metal powder and a foaming assistant powder that decomposes by heating to generate gas;
A laminating step of obtaining a laminate composed of at least three layers in which a mixed powder layer composed of the mixed powder is disposed between the metal plate and the restraint plate;
A heating and foaming step of melting the metal powder by heating the laminate and foaming the foaming auxiliary powder;
It is characterized by including.
The composite vibration-damping metal plate of the present invention includes a metal foam layer. Since the metal foam layer is laminated on the metal plate, sufficient strength can be maintained even if the bubble rate is high. Since the metal foam layer is partially bonded to the surface of the metal plate, a gap is formed at the interface between the metal plate and the metal foam layer, and the metal plate and the metal foam layer are also formed at the interface. vibration energy is absorbed by frictional energy by vibrations between. As a result, vibration control is further enhanced.
The composite vibration-damping metal plate of the present invention is easily manufactured by heating a mixed powder of a metal powder and a foaming aid powder that decomposes by heating to generate gas and laminated on the surface of the metal plate. Is possible. By heating the mixed powder between the metal plate and the constraining plate, a composite vibration-damping metal plate in which the metal foam layer is appropriately bonded to the surface of the metal plate is obtained.

FIG. 1 is an explanatory view of the method for manufacturing a composite vibration-damping metal plate of the present invention, and is a cross-sectional view in the thickness direction of the composite vibration-damping metal plate.
FIG. 2 is a cross-sectional view schematically showing an example of the composite vibration-damping metal plate of the present invention, and is a cross-sectional view in the thickness direction.
FIG. 3 is a drawing-substituting photograph showing a cross section of the composite vibration-damping metal plate of Example 1.
FIG. 4 is a graph showing the damping performance of the composite damping metal plate of Example 1, and also shows the damping performance of the foamed aluminum.
FIG. 5 shows a cross-sectional view of a metal foam made of pure aluminum, a 6061 alloy, and an aluminum alloy containing 7% by mass of silicon.
FIG. 6 is a graph showing the bubble ratio (area%) of each metal foam shown in FIG.
FIG. 7 shows an average cell diameter and a cross-sectional view of a metal foam made of an aluminum alloy containing 7% by mass of pure aluminum and silicon.
FIG. 8 is a graph showing the cell ratio (area%) of a metal foam made of an aluminum alloy containing 7% by mass of silicon.
FIG. 9 is a graph showing the relationship between the temperature and liquid phase ratio of aluminum alloys having different compositions and pure aluminum.

The best mode for carrying out the composite vibration-damping metal plate and the manufacturing method thereof of the present invention will be described below.
[Composite damping metal plate]
The composite damping metal plate of the present invention (hereinafter abbreviated as “damping metal plate”) has a metal plate and a metal foam layer laminated on the metal plate. Below, each of a metal plate and a metal foam layer is demonstrated.
The metal plate should just consist of a metal material which is excellent in mechanical strength than a metal foam. Therefore, what is necessary is just to select suitably according to the use of a damping metal plate. For example, from the viewpoint of weight reduction, an aluminum plate, an aluminum alloy plate, a magnesium plate, a magnesium alloy plate, or the like can be used. In order to further improve the mechanical strength, a metal plate made of various steel materials, copper, copper alloy, manganese, manganese alloy, titanium, titanium alloy, or the like may be used. Further, when it is desired to further improve the damping performance, it is preferable to use a metal plate made of damping alloy such as magnesium or magnesium alloy, iron-based alloy, copper alloy or manganese alloy. Specifically, in addition to iron-based damping alloys mainly composed of iron such as flake graphite cast iron, spheroidal graphite cast iron, Fe-Al-Mn alloy, Fe-Cr alloy, Al-Zn superplastic alloy, Examples thereof include damping alloys such as Co—Ni alloys, Mg—Zr alloys, Cu—Mn—Al alloys, Cu—Zn—Al alloys, Ni—Ti alloys, and the like. The damping alloy has a loss coefficient η of 0.01 or more.
The thickness of the metal plate is not particularly limited, and may be appropriately selected according to the use of the vibration-damping metal plate of the present invention. If it is specified, it is preferably 0.5 mm or more, and more preferably 1 mm or more. If the thickness of the metal plate is less than 0.5 mm, the mechanical strength is insufficient and it is difficult to manufacture the vibration-damping metal plate.
The metal foam layer is partially bonded to the surface of the metal plate. That is, the vibration-damping metal plate of the present invention is integrated in a state where the metal plate and the metal foam layer are laminated. The metal plate and the metal foam layer may have a three-layer structure such as a metal plate / metal foam layer / metal plate in addition to a two-layer structure having one layer each. Further, a structure of four or more layers may be alternately laminated. At this time, each of the metal foam layers may be sandwiched between metal plates. When the structure has three or more layers, the metal forming each metal plate and metal foam layer may be the same or different. Further, from the viewpoint of strength, it is preferable that at least one of the outermost layers (located on both end surfaces in the thickness direction) be a metal plate.
In addition, the state in which the metal foam layer is partially bonded to the surface of the metal plate is not a state in which the metal plate and the metal foam layer are in close contact with each other on the entire surface of the laminated interface. A substantial gap is present between the plate and the metal foam layer so that the substantial bonding area is reduced.
The metal foam layer may have a cell ratio of 50 area% or more and 70 area% or less. In the present specification, the “bubble ratio” is the ratio of the total area of the bubble portion calculated by automatic image recognition to the 100% area of the entire cross section calculated by automatic image recognition in the cross section of the metal foam. I will do it. If the bubble ratio is 55 area% or more, further 60 area% or more, it is preferable because the vibration damping property is improved as well as the lightening effect. However, since the strength decreases as the bubble rate increases, the bubble rate is preferably 70 area% or less, more preferably 65 area% or less. In the sintered body, it is difficult to increase the porosity (that is, the bubble ratio) in terms of the strength of the sintered body and the manufacturing process.
Further, the smaller the average bubble diameter of the bubbles present in the metal foam layer, the higher the energy absorption capacity, and the damping performance of the damping metal plate of the present invention is improved. Therefore, the average cell diameter of the metal foam layer is preferably 3 mm or less, and more preferably 2 mm or less. In the present specification, the “average bubble diameter” is an arithmetic average value of measured values obtained by observing a cross section of a metal foam and measuring the maximum diameter of about 200 to 300 bubbles. The lower limit of the average cell diameter is not particularly limited, but is preferably 1.2 mm or more, further 1.5 mm or more. This is because a metal foam having an average cell diameter of less than 1.2 mm is difficult to produce and a great improvement effect of vibration damping cannot be expected.
There is no limitation in particular in the thickness of a metal foam layer, What is necessary is just to select suitably according to the use of the damping metal plate of this invention. If stipulated, it is preferably 0.3 mm or more and 1.5 mm or less, more preferably 0.5 mm or more and 1 mm or less. If the thickness of the metal foam layer is less than 0.3 mm, the thickness of the metal foam layer is too thin relative to the size of the bubbles, causing problems in terms of strength and manufacturing, and a great improvement in vibration damping can be expected. Absent. However, if the average cell diameter is small, the strength is maintained and the manufacturing difficulty is reduced even if the thickness of the metal foam layer is reduced. Further, if the metal foam layer is sandwiched between the metal plates, the strength is maintained even if the thickness of the metal foam layer is reduced, and the manufacture is easy. On the other hand, if the metal foam layer exceeds 1.5 mm, the strength becomes insufficient, such being undesirable. The ratio between the thickness Tb of the metal plate and the thickness Tp of the metal foam layer is preferably Tb: Tp = 1: 0.5-1.
The metal foam layer is not limited to the type of metal, and may be composed of a general metal foam such as aluminum, steel, copper, nickel, titanium or the like. Among these, foamed aluminum is desirable because it is lightweight and can impart strength by containing silicon. In addition, the metal foam layer made of an aluminum alloy containing silicon has a high bubble ratio and has fine and uniformly dispersed bubbles, which is effective in terms of energy absorption and vibration damping. Below, the aluminum foam optimal for the metal foam layer of the damping metal plate of this invention is demonstrated.
Foamed aluminum is a porous body made of aluminum or an aluminum alloy. Foamed aluminum made of an aluminum alloy containing silicon (Si) is preferable because it is lightweight and has higher strength than foamed aluminum made of pure aluminum. In an aluminum alloy containing Si, the Si content is preferably not less than the solid solubility limit and less than the Si amount at the eutectic point. The “solid solubility limit” and “eutectic point” representing the Si content are defined in the equilibrium diagram of the Al—Si binary alloy, and are “above the solid solubility limit and less than the Si amount at the eutectic point”. "Is specifically expressed by a numerical value, it is 1.66 mass% or more and less than 11.7 mass%. When the Si amount is equal to or greater than the Si amount at the eutectic point, hard primary crystal Si is crystallized, the metal foam itself becomes hard, and vibration damping properties are lowered, which is not preferable. The metal foam having a Si content of 3% by mass or more, 5% by mass or more, further 6% by mass or more, 10% by mass or less, and further 9% by mass or less when the aluminum alloy is 100% by mass is a fine cell. Is more preferable because it is easy to produce a metal foam having a high cell rate (described later). In addition to Si and inevitable impurities, the aluminum alloy may contain one or more alloy elements generally contained in aluminum alloys such as Cu, Fe, Mg, Mn, Cr, and Ti. However, the content of these elements is less than the content of silicon.
Since the composite vibration-damping metal plate of the present invention is excellent in vibration damping and mechanical strength, it has a bumper beam that requires shock absorption, a side frame that requires shock absorption and rigidity, a hood, vibration damping and soundproofing. It can be used as automotive structural materials such as required floor panels and dashboards. In addition, the present invention can be applied to a rod that supports a plurality of healds in a frame of a loom. Since the rod collides with the heald during operation of the loom, it causes vibration and noise. The composite vibration-damping metal plate of the present invention is excellent in mechanical strength and can be formed with a small thickness. Therefore, the composite vibration-damping metal plate is suitable for a rod of a cocoon frame and reduces vibration and noise generated during operation of the loom. Can do.
The composite vibration-damping metal plate of the present invention is produced by melting a mixed powder of a metal powder and a foaming aid powder that decomposes by heating to generate a gas on the surface of the metal plate and foaming the foaming aid powder. it can. It is also possible to produce a metal foam having a predetermined size and shape in a plate shape and weld it to the metal plate or bond it with an adhesive to join it. In addition, when forming a metal powder into a plate shape, a metal plate and a metal foam layer made of a sintered body are contained by heating and containing a metal powder and a foaming aid powder that are easily melted only in the portion to be foamed. A composite vibration-damping metal plate consisting of Below, the desirable manufacturing method which can manufacture the damping metal plate of this invention is demonstrated.
[Production method of composite vibration-damping metal plate]
In the method for manufacturing a damping metal plate of the present invention, a composite damping metal plate in which the metal foam layer is partially bonded to the surface of the metal plate is obtained. The manufacturing method of the damping metal plate of this invention manufactures a damping metal plate mainly through a preparation process, a lamination process, and a heating foaming process. Below, each process is demonstrated.
The preparation step is a step of preparing a mixed powder of a metal powder and a foaming aid powder that decomposes by heating to generate gas. What is necessary is just to mix the metal powder and foaming auxiliary agent powder which were weighed so that it might become a predetermined mass ratio with the mixer generally used for mixing of powder. At this time, a lubricant, a binder or the like may be added as necessary. When the total amount of the metal powder and the foaming auxiliary powder is 100% by mass, the content of the foaming auxiliary powder is 0.3% by mass to 1.5% by mass, and further 0.4% by mass to 1%. It is good to be less than mass%. If the content of the foaming auxiliary powder is less than 0.3% by mass, a metal foam layer having a high cell rate cannot be obtained, which is not desirable. As the content of the foaming aid powder increases, a metal foam having a higher cell ratio is more easily formed. However, when the content is 1.5% by mass or less, formation of coarse bubbles is suppressed.
What is necessary is just to select a metal powder suitably according to the composition of the metal foam layer to produce. In order to obtain a metal foam layer made of an alloy, two or more kinds of metal powders may be mixed and used in accordance with the composition of the alloy, or an alloy powder having the composition of the alloy may be used. Use of alloy powder is desirable because a metal foam layer having a uniform composition can be obtained. For example, in order to obtain a metal foam layer made of an aluminum alloy containing silicon, an alloy powder made of an aluminum alloy containing silicon may be used. What is necessary is just to select the composition of an aluminum alloy according to the alloy composition of the metal foam to manufacture. However, from the viewpoint of foamability, it is desirable that the content ratio of silicon (Si) is not less than the solid solubility limit and less than the Si amount at the eutectic point. The foamability will be described in the description of the heating foaming process.
As the metal powder, a powder obtained by pulverizing an ingot or pulverizing a molten metal can be used. For example, atomized powder is commercially available and can be easily obtained. The average particle size of the metal powder is not limited, but a size generally used for the production of a metal foam of 150 μm or less is desirable.
The foaming auxiliary powder is decomposed by heating to generate gas. As the foaming aid powder, a powder generally used for the production of metal foams may be used. For example, titanium hydride (TiH ₂ ), magnesium carbonate (MgCO ₃ ), calcium carbonate (CaCO ₃ ), and the like can be given. In particular, when an aluminum alloy containing silicon is used, TiH ₂ that decomposes at 500 to 600 ° C. to generate hydrogen gas is optimal.
A lamination process is a process of obtaining the laminated body which consists of an at least 3 layer which has arrange | positioned the mixed powder layer which consists of mixed powder between a metal plate and a restraint board. A lamination process will be described with reference to FIG. FIG. 1 is an explanatory view of a method for manufacturing a damping metal plate according to the present invention, and is a cross-sectional view in the thickness direction (that is, the lamination direction) of the damping metal plate. A mixed powder layer 2 ′ made of mixed powder is laminated on the surface of the metal plate 1a. Further, a constraining plate 1b is laminated on the mixed powder layer 2 ′. The constraining plate 1b may be laminated in contact with the mixed powder layer 2 ′, or a slight gap may be provided. When the gap is provided, the distance between the opposing surfaces of the metal plate 1a and the restraining plate 1b is fixed so as to be the thickness of the metal foam layer of the vibration-damping metal plate to be produced. Further, the laminate may be compressed in the thickness direction. Alternatively, a molding step may be performed in which the mixed powder obtained in the above preparation step is molded to obtain a plate-shaped molded body, and the plate-shaped molded body may be disposed between the metal plate and the constraining plate in the lamination step. . At this time, it is desirable that the mixed powder layer and the plate-shaped molded body are compressed so that the porosity is 1% by volume or less, further 0.8% by volume or less.
In the laminating step, the constraining plate 1b is preferably a graphite plate. Since the graphite plate has poor bondability with the metal foam layer, it only plays a role of restraining the growth of the metal foam in the thickness direction. In this case, a damping metal plate having a two-layer structure of a metal plate and a metal foam layer can be manufactured. Further, by sandwiching the graphite plate in the middle, it is possible to produce two or more vibration-damping metal plates at a time. Further, in the laminating step, the restraint plate 1b may be another metal plate that constitutes the vibration-damping metal plate. That is, the lamination process may be a process of alternately laminating the mixed powder layer and two or more metal plates. In FIG. 1, if the constraining plate 1b is a metal plate, it is possible to manufacture a vibration-damping metal plate (lower diagram in FIG. 1) having a three-layer structure including the metal plate 1a / metal foam layer 2 / metal plate 1b. And it becomes possible to manufacture the damping metal plate of the further multilayered structure by laminating | stacking several metal plates through a mixed powder layer. For example, as shown in the sectional view of FIG. 2, the metal foam layer 2a is between the

metal plates

1a and 1b, the metal foam layer 2b is between the

metal plates

1b and 1c, and the

metal plates

1c and 1d are between A damping metal plate is obtained in which the metal foam layer 2c is sandwiched between the two. As described above, the metal plates 1a to 1d and the metal foam layers 2a to 2c may have the same composition or different compositions. However, the larger the number of layers, the more compressed by its own weight in the thickness direction, so the porosity of the mixed powder layer and the plate-shaped laminate decreases, or the adhesion at the interface between the metal plate and the metal foam layer is required There are problems such as improvement. Since these problems lead to a decrease in vibration damping properties, the total number of metal plates and metal foam layers is preferably 2 to 10 layers, and more preferably 3 to 5 layers.
Moreover, you may pre-process a metal plate before a lamination process. For example, you may adjust the joining area of a metal plate and a metal foam layer by apply | coating a mold release agent beforehand to a part of surface of a metal plate. Partial joining of the metal plate and the metal foam layer can be intentionally generated.
The heating and foaming process is a process of melting the metal powder by heating the laminate and foaming the foaming auxiliary powder. A composite vibration-damping metal plate in which the metal foam layer is partially bonded to the surface of the metal plate is obtained by heating the laminate having the above-described configuration and melting and foaming the mixed powder layer or the plate-like laminate. . The heating may be performed using a heating furnace that is usually used for manufacturing metal foams. Heating may be performed in a vacuum or in an inert gas atmosphere.
When the metal powder is an alloy powder, the laminated body is heated to the solidus temperature T _S or higher so that the alloy powder is in a semi-molten state, and at the same time, the foaming aid powder is decomposed and bubbles are generated. Will expand. At this time, it is desirable that the heating temperature in the heating and foaming process does not exceed the liquidus temperature _TL of the alloy. When the heating temperature of the laminate exceeds _TL , the foamability becomes excessively high, and it becomes difficult to form fine bubbles.
Further, in the heating foaming process, in order to obtain a fine and such bubbles uniformly dispersed can be obtained good foaming properties, the difference between the above T _S and T _L are somewhat necessary. When the difference between T _S and T _L is small, proportion of the liquid phase is increased in the alloy of the semi-molten state as soon as more than T _S, or become bubbles between the bubbles adjacent excessively grow is likely to adhesions This is because it is considered. That is, the heating temperature in the heating and foaming process can be defined by the liquid phase rate. If the heating and foaming step is performed at a liquid phase ratio of 70% by mass or more and 90% by mass or less, and further 75% by mass or more and 85% by mass or less, the growth and adhesion of bubbles are suppressed due to the presence of an appropriate solid phase, and the liquid phase ratio is fine. It is easy to obtain bubbles that are uniformly dispersed. In other words, regardless of the Si content, it is desirable to perform the heating and foaming step at a temperature that falls within the range of the liquid phase ratio.
When the metal foam layer is made of an aluminum alloy containing silicon, fine and uniformly dispersed bubbles are formed with the following composition. FIG. 9 is a graph showing the relationship between the temperature and the liquid phase ratio of Al—Si alloys having different Si contents. In the figure, the number described before Si is the Si content [% by mass] when the Al—Si alloy is 100% by mass. Also, temperatures of pure aluminum (including about 1% by mass of impurities) and 6061 (Al—Mg—Si based alloy defined by JIS, Mg: 0.75% by mass, Si: 0.68% by mass) The relationship between the liquid phase ratio and the liquid phase ratio is also shown. From FIG. 9, in order to obtain fine and uniformly dispersed bubbles, the content of silicon is 5% by mass or more, further 6% by mass or more when the aluminum alloy is 100% by mass in consideration of the liquid phase ratio. It turns out that it is good to use the aluminum alloy powder which is 10 mass% or less, further 9 mass% or less. In other words, the metal foam layer having a silicon content within this range has fine and uniformly dispersed bubbles. From FIG. 9, when the silicon content exceeds 10% by mass, it is difficult to make the liquid phase ratio 70 to 90%, which is not desirable. Further, for example, when an aluminum alloy containing 7% by mass of Si shown as “7Si” in FIG. 9 (abbreviated as “Al-7% Si alloy”) is used as the alloy powder, the solid solution of the Al-7% Si alloy is used. The phase line temperature is T _S = 580 ° C., the liquidus temperature is T _L = 630 ° C., and it is desirable to perform the heating and foaming step at a temperature of 590 ° C. or more and 625 ° C. or less, further 600 ° C. or more and 620 ° C. or less.
There is no particular limitation on the rate of temperature increase when the laminate is heated, but it is preferable to increase the temperature to the predetermined temperature at 10 to 20 ° C./min. Further, immediately after the laminated body reaches a predetermined temperature, or after holding the molded body at a predetermined temperature for a predetermined time, the metal in a semi-molten state containing bubbles is cooled and solidified, thereby damping the metal foam layer. A metal plate is obtained. In the case of a metal foam layer made of an aluminum alloy, the holding time is preferably 0 to 30 minutes, more preferably 0 to 20 minutes. This is because, if held for a long time, bubbles tend to grow even at a relatively low temperature, but holding for 30 minutes or more does not particularly affect the growth of bubbles. Moreover, the unevenness | corrugation which generate | occur | produces on the surface of a metal foam layer is suppressed when a metal foam layer is not clamped by the metal plate by making holding time into 20 minutes or less. Cooling may be performed under the condition that the metal is solidified with the bubbles kept in a desired shape, and air cooling with a cooling rate of about 200 to 300 ° C./min is desirable.
Incidentally, in the cooling process, because components of the blowing aid powder (if TiH ₂ Ti) is but a solid solution in the metal, which as already mentioned, foaming aid powder is only used a small amount, the metal foam There is no adverse effect on the properties of the metal constituting the body layer.
As mentioned above, although embodiment of the composite damping metal plate of this invention and its manufacturing method was described, this invention is not limited to the said embodiment. The present invention can be implemented in various forms without departing from the gist of the present invention, with modifications and improvements that can be made by those skilled in the art.
Hereinafter, the present invention will be specifically described with reference to examples of the composite vibration-damping metal plate and the method for producing the same according to the present invention.

[Production of composite damping metal plate]
(Preparation step) Al-7% Si alloy powder (average particle size: 70 μm) was prepared as the alloy powder, and TiH ₂ powder was prepared as the foaming aid powder. TiH ₂ powder was 45μm or less by sieve. Al-7% Si alloy powder and TiH ₂ powder were mixed by a ball mill to obtain a mixed powder. The mixing ratio was 100% by mass of the mixed powder and 0.5% by mass of the TiH ₂ powder.
(Molding step) The mixed powder was formed into a rod shape having a diameter of 12 mm and a length of 10 mm by uniaxial pressing and then rolled in order in the longitudinal direction to a thickness of 1 mm to obtain a plate-like precursor.
(Lamination process) A plate-like precursor cut out to 20 mm x 180 mm is placed on a damping alloy plate (20 mm x 180 mm x thickness 1 mm) made of a Fe-Al-Mn-Cr alloy, and further a plate-like precursor. A similar damping alloy plate was placed on the top. Thus, a laminate having a thickness of 3 mm was obtained. The laminate was fixed so that the thickness did not change during processing.
Was (heating and foaming step) foaming a TiH ₂ powder with an alloy powder by heating in a vacuum atmosphere in an infrared large image furnace laminate (hereinafter referred to as "furnace") and a semi-molten state. The plate-like precursor was preheated at 500 ° C. for 20 minutes, then heated to a predetermined temperature at 15 ° C./minute, held at 600 ° C. for 5 minutes, then removed from the heating furnace and air-cooled at 4 ° C./second.
A cross-sectional photograph of the composite vibration-damping metal plate of this example obtained by the above procedure is shown in FIG. In the above laminating step, the layers were laminated in order from the bottom. The obtained composite vibration-damping metal plate was provided with two vibration-damping alloy plates and a foamed aluminum layer made of an aluminum alloy containing silicon sandwiched between them, each having a thickness of 1 mm. . At the interface between the vibration-damping alloy plate and the foamed aluminum layer, a bonded portion where both were bonded and a non-bonded portion where they were not bonded were observed.
The foamed aluminum layer included in the composite vibration-damping metal plate of Example 1 had a cell ratio of 60 area% and an average pore diameter of 1.82 mm. The bubble ratio is the ratio (area%) of the total area of the bubble portion calculated by automatic image recognition to the area of 100% of the entire cross section calculated by automatic image recognition in the cross section of the metal foam layer shown in FIG. Asked. Moreover, the average bubble diameter measured the maximum diameter of the diameter of all the bubbles observed in the cross section of the thickness direction of a metal foam, and calculated | required the arithmetic average value.
[Evaluation: Vibration control]
The obtained composite damping metal plate (thickness 3 mm) was cut out to 10 mm × 160 mm to prepare a test piece, and the loss factor was measured by the central vibration method. The center excitation method is a method in which the center part of a test piece fixed with a triangular jig is subjected to random excitation (amplitude: 1.0 × 10 ⁻⁷ to 1.0 × 10 ⁻⁵ , frequency: 20000 Hz or less). Then, the loss coefficient η is calculated from the frequency response function obtained by the excitation by the half width method. For the measurement of the frequency response function, DS-2000 manufactured by Ono Sokki was used. The results are shown in FIG.
For comparison, the damping property of foamed aluminum (thickness 1 mm) produced in the same manner as in Example 1 was measured in the same manner except that a graphite plate was used instead of the damping metal plate. The results are shown in FIG. Although not shown, the loss coefficient η of the damping alloy plate made of the Fe—Al—Mn—Cr alloy is located between the example and the comparative example in FIG.
The sample of Example 1 had a loss coefficient η of about 0.04 to 0.08, and showed a high damping capacity comparable to that of the resin material. In the case of only foamed aluminum, the damping capacity is greatly improved compared to the case of only the damping metal plate, because the damping metal plate and the foamed aluminum layer are partially joined, and the interface between the two This is also because the vibration energy is absorbed. In addition, it consists of an aluminum alloy whose Si content rate is 6.5 mass% or more and 7.5 mass% or less, a bubble rate is 57 area% or more and 63 area% or less, and an average bubble diameter is 1.6 mm or more and 1.9 mm or less. If it is a metal foam, it is an error range, and it is thought that the damping capacity equivalent to the composite damping metal plate of Example 1 is shown.
[Reference example]
Below, the manufacturing method of the metal foam which consists of aluminum or an aluminum alloy is shown as a reference example. The produced metal foam is cut out as it is or into a predetermined size and joined to various metal plates to obtain a composite vibration-damping metal plate.
[Production of metal foam]
(Preparation step) Al-7% Si alloy powder, 6061 alloy powder and pure Al powder were prepared as metal powders. The average particle diameter of these metal powders was about 70 μm for Al-7% Si alloy powder and about 30 μm for pure Al powder. Further, as a foaming aid powder were used TiH ₂ powder. TiH ₂ powder was 45μm or less by sieve. Al-7% Si alloy powder, 6061 alloy powder or pure Al powder, and TiH ₂ powder were mixed by a ball mill to obtain a mixed powder. The mixing ratio was 100% by mass of the mixed powder and 0.5% by mass of the TiH ₂ powder.
(Molding step) The mixed powder was formed into a rod shape having a diameter of 12 mm and a length of 10 mm by uniaxial pressing and then rolled in order in the longitudinal direction to a thickness of 1 mm to obtain a plate-like precursor.
(Heating and foaming step) A plate-like precursor cut into 20 mm x 180 mm is heated in a vacuum atmosphere in an infrared large image furnace (hereinafter abbreviated as "heating furnace") to make the metal powder in a semi-molten state and to foam TiH ₂ powder. It was. The plate-like precursor was preheated at 500 ° C. for 20 minutes, then heated to a predetermined temperature at 15 ° C./minute, taken out from the heating furnace when the predetermined temperature was reached, and air-cooled at 4 ° C./second. The temperature at the time of taking out is 560 ° C. lower than the solidus temperature (T _S = 580 ° C.) of the Al-7% Si alloy, and 580 to 620 ° C. above T _{S and} lower than the liquidus temperature (T _L = 630 ° C.). And a plurality of metal foams were produced by changing the temperature in the range of 640 to 750 ° C. above _TL . In addition, the temperature in a heating foaming process is the value which measured the temperature in a heating furnace with a thermocouple. FIG. 5 shows cross-sectional photographs in the thickness direction of the metal foams produced using the mixed powders, for each temperature taken out.
Whichever metal powder was used, a metal foam having bubbles was obtained by melting the metal powder and foaming the TiH ₂ powder. When pure Al powder was used, the bubbles formed at 690 ° C. or lower grew in a crack shape so as to peel in the thickness direction in the plate-like precursor. Similarly, when 6061 alloy powder was used, bubbles formed at 660 ° C. or lower grew in a crack shape so as to peel in the thickness direction within the plate-like precursor. This is because the foaming of TiH ₂ powder was actively generated while the temperature was low and the liquid phase ratio was low. In all cases, when the temperature rose, bubbles that were nearly circular were formed.
On the other hand, when the Al-7% Si alloy was used, the plate-like precursor was only warped at 560 ° C. below the solidus temperature. By heating above the solidus temperature, fine bubbles were uniformly dispersed and formed. However, when the temperature rose above the liquidus temperature, the bubbles grew greatly, and many large bubbles exceeding 3 mm were observed above 700 ° C.
[Evaluation: Measurement of average bubble diameter and bubble ratio]
The average bubble diameter and bubble ratio of the produced metal foam were measured in the same manner as described above. In addition, the measurement of the average bubble diameter was measured about the metal foam which consists of an Al-7% Si alloy taken out at 580 degreeC or 600 degreeC. The results were 0.58 mm (580 ° C.) and 0.83 mm (600 ° C.), respectively. Moreover, the bubble rate of each metal foam with respect to taking-out temperature is shown in FIG. It was found that when the 6061 alloy powder was used and when the pure Al powder was used, both the bubble ratio and the average bubble diameter tended to increase as the temperature increased. However, when the temperature became too high, the hydrogen inside the greatly expanded bubbles escaped outside, and the foam contracted. On the other hand, when Al-7% Si alloy powder is used, it is considered that fine spherical bubbles formed at 580 ° C. grow as they are and increase the bubble rate. However, coarse bubbles were observed at 640 ° C. or higher. This is presumably because the bubbles accounted for too much or the adjacent bubbles easily adhered to each other because the liquid phase accounted for 100%.
Further, as described above, if the heating temperature is too high, there is a possibility that bubbles will become large. However, when Al-7% Si alloy powder is used, it is considered that fine bubbles can be generated uniformly by heating the liquid phase ratio to about 70 to 90%. Therefore, when the silicon content is 7% by mass or more, an optimum liquid phase ratio can be obtained even at a lower heating temperature. Therefore, considering FIG. 9, if the Si content is 7% by mass or more and 10% by mass or less, there is a high possibility that fine bubbles can be generated uniformly.
[Preparation of sheet metal foam]
Next, a plate-like precursor (thickness 1 mm) made of Al-7% Si alloy powder and TiH ₂ powder produced by the above procedure was cut into 70 mm × 18 mm, and placed between two graphite plates, A plate-shaped metal foam was produced by heating in a heating furnace. The plate-like precursor was placed at the center of one graphite plate. Spacers with a thickness of 3 mm were fixed at the four corners of the graphite plate, and another graphite plate was placed and fixed thereon. The lower graphite plate is provided with an insertion hole that opens to the end surface and extends to the central portion. A thermocouple was inserted into the insertion hole, and the temperature of the central portion on which the plate-like precursor was placed was measured. Note that the graphite plate is merely a restraint plate, and after cooling through the heating and foaming step, the plate-like metal foam and the graphite plate are easily separated.
The plate-like precursor is preheated at 500 ° C. for 20 minutes, then heated up to a predetermined temperature at 15 ° C./minute, and the time (holding time) from reaching the predetermined temperature to taking out is 0, 5, 15, 30, 60 minutes. A plurality of plate-like metal foams were produced. The heating temperature (holding temperature) during the holding time was constant. The cooling rate after removal was set to 4 ° C./second (air cooling). A cross-sectional photograph in the thickness direction of the metal foam with a holding temperature of 600 ° C. is shown in FIG. 7 for each holding time.
Further, a plate-shaped metal foam was produced in the same manner for a plate-shaped precursor (thickness 1 mm) made of pure Al powder and TiH ₂ powder. However, the holding temperature was 660 ° C.
[Evaluation: Measurement of average bubble diameter and bubble ratio]
The average cell diameter and cell rate (only Al-7% Si alloy) of the metal foam produced by the above procedure were measured. The results are shown in FIG. 7 and FIG.
When the plate-like metal foam made of an Al-7% Si alloy is taken out when it reaches 640 ° C. (not shown) and kept at 600 ° C. for 5 minutes or more, the upper side is caused by foaming of TiH ₂ powder. In contact with the graphite plate. In addition, when the holding temperature was 580 ° C. or higher, the effect of increasing the bubble ratio was observed by taking the holding time. However, no significant changes were observed in the bubble rate and bubble diameter even when held for 30 minutes or longer. In particular, by holding at 600 ° C. for 5 to 15 minutes, a plate-like metal foam having a cell ratio exceeding 50 area% and an average cell diameter of less than 2 mm was obtained.
Further, the plate-like metal foam made of pure Al grew like a crack so as to peel in the thickness direction in the plate-like precursor without holding time. However, by holding for 5 minutes or more, bubbles having small diameters were generated, and a metal foam layer having bubbles uniformly dispersed as a whole was formed.

Claims

A composite damping metal plate having a metal plate and a metal foam layer laminated on the metal plate,
The composite vibration-damping metal plate, wherein the metal foam layer is partially bonded to the surface of the metal plate.
2. The composite vibration-damping metal plate according to claim 1, wherein the metal foam layer has an area ratio of 50 area% to 70 area% in area ratio.
The composite vibration-damping metal plate according to claim 1, wherein the metal foam layer is made of foamed aluminum.
The composite vibration-damping metal plate according to claim 3, wherein the foamed aluminum is made of an aluminum alloy containing silicon.
The composite vibration-damping metal plate according to claim 1, wherein the metal plate is made of a vibration-damping alloy.
The composite vibration-damping metal plate according to claim 5, wherein the vibration-damping alloy is an iron-based vibration-damping alloy containing iron as a main component.
The composite vibration-damping metal plate according to claim 1, wherein the composite vibration-damping metal plate has a multilayer structure composed of three or more layers in which the metal plate and the metal foam layer are alternately laminated.
The composite vibration-damping metal plate according to claim 7, wherein each of the metal foam layers is sandwiched between the metal plates.
The metal foam layer is formed by melting a mixed powder of a metal powder and a foaming auxiliary powder that decomposes by heating to generate gas on the surface of the metal plate and foaming the foaming auxiliary powder. The composite vibration-damping metal plate described.
A method of manufacturing a composite vibration-damping metal plate having a metal plate and a metal foam layer laminated on the metal plate,
A preparation step of preparing a mixed powder of a metal powder and a foaming assistant powder that decomposes by heating to generate gas;
A laminating step of obtaining a laminate composed of at least three layers in which a mixed powder layer composed of the mixed powder is disposed between the metal plate and the restraint plate;
A heating and foaming step of melting the metal powder by heating the laminate and foaming the foaming auxiliary powder;
A method for producing a composite vibration-damping metal plate, comprising:
Furthermore, it includes a forming step of forming the mixed powder obtained in the preparation step to obtain a plate-like formed body, and the laminating step arranges the plate-like formed body between the metal plate and the constraining plate. The method of manufacturing a composite vibration-damping metal plate according to claim 10, wherein
11. The constraining plate is another metal plate constituting the composite vibration-damping metal plate, and the laminating step is a step of alternately laminating the mixed powder layer and two or more metal plates. The manufacturing method of the composite damping metal plate of description.
The composite vibration-damping metal plate according to claim 10, wherein the metal powder is made of an alloy, and the heating and foaming step is a step of heating the laminate to a temperature not lower than a solidus temperature of the alloy and not higher than a liquidus temperature. Production method.
The method of manufacturing a composite vibration-damping metal plate according to claim 13, wherein the metal powder is an aluminum alloy powder containing silicon, and the foaming auxiliary powder is TiH 2 powder.