JPS6220758B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an acoustic diaphragm with excellent acoustic characteristics and workability. Conventionally, Mg,
Al, B, Be, Ti and Al-Cu-Mg alloys are known, and their properties are as shown in Table 1.

[Table] To briefly explain the characteristics of these conventional acoustic diaphragm materials, (i) Mg...The density is small and light, but the sound velocity (√elastic modulus/density) is slightly low at 5060 (m/s). ,
Furthermore, since the activity is high, oxidation is severe, making it difficult to form a thin plate by high-temperature processing in air. (ii) Be...It is an extremely excellent material in terms of density, elastic modulus, sound velocity, etc., but it is toxic to the human body and is highly oxidized, so it cannot be deposited by vapor deposition.
Thin films cannot be made without using techniques such as chemical vapor deposition.
It is difficult to convert bulk materials into thin ribbons using normal processing methods. (iii) B: It has excellent density, elastic modulus, sound velocity, etc., but is extremely hard to process due to its large hardness (Vickers hardness Hv = 3500 Kg/mm ² ) and high melting point (2225°C). It is difficult to convert bulk materials into thin strips using normal processing methods such as rolling, so they are processed into pipe shapes using methods such as chemical vapor deposition, or deposited on thin Al plates to achieve their characteristics. There are problems in terms of cost and productivity. (iv) Ti: Although it has a high elastic modulus, there is a problem that the speed of sound is low due to its high density. (v) Al and Al-based alloys are widely used in acoustic diaphragms and have a low density (2690
Kg/m ³ ), it has very good workability and can be easily made into a thin strip by rolling, etc., but its elastic modulus is 7.0 ×
10 ¹⁰ (N/m ² ), which is rather small, and the sound speed is 5000 m/m
sec, the sound speed of Be, B, etc. is 12000 (m/sec)
The problem is that it is far behind. The purpose of the present invention is to provide a material with excellent processability.
An object of the present invention is to provide an Al alloy diaphragm in which the low sound velocity, which is a drawback of Al-based alloys, is improved by crystal orientation. ~
Contains 18.9at% Mg and has (111) crystals,
(211) or (110) plane, and furthermore, the crystal plane and crystal orientation are (111)<110>, (111)<
211＞, (211)＜110＞, (211)＜111＞, (110)＜
110>, (110)<111>, and (110)<211>. Furthermore, in the manufacturing method, the circumferential surface of the metal roller that rotates the Al-Mg alloy molten metal,
Alternatively, it is characterized in that it is sprayed onto the surface gap between a pair of metal rollers rotating in opposite directions to form a thin ribbon while being ultra-quickly cooled. As a result of selecting the most suitable material for the diaphragm material from the viewpoint of low density and high elastic modulus, the present inventors found that Al-Mg alloy was particularly excellent, and by further orienting this alloy, extremely excellent acoustics could be achieved. It was discovered that this material has excellent characteristics as a diaphragm for use. Generally, the elastic modulus of a metal material differs depending on the direction of the crystal axis, and in a polycrystalline material, the elastic modulus is the average value in each crystal axis direction. From these facts, in acoustic diaphragms made of Al-Mg alloys, the elastic modulus E ₍₁₁₁₎ is 7.5 × 10 ¹⁰ for crystal-oriented diaphragms with (111) planes in the plate plane.
(N/m ² ), and when the (110) or (211) plane is oriented within the plate plane, E ₍₂₁₁₎ >> E ₍₁₁₀₎ = 7.2×10 ¹⁰
(N/m ² ). However, in the case of a non-oriented polycrystalline diaphragm, the value of Epoly is as small as 70×70 ¹⁰ (N/m ² ). In the present invention, a diaphragm with excellent characteristics is obtained by utilizing (111), (211), or (110) plane orientation by crystal orientation. In order to manufacture this crystal-oriented Al-Mg-based diaphragm, the present inventors added various additives, created a solid solution thereof, processed it into a metal ribbon, and determined the crystal orientation using X-ray diffraction. Measured by. Here, as an example of the degree of crystal orientation (111)
The degree of plane orientation Q ₍₁₁₁₎ was defined by the following equation. Q ₍₁₁₁₎ = [(ΣI _(hhh) / ΣI _(hkl) ) − (ΣI゜_(hhh) / ΣI゜_(hkl) ] / [1 − (ΣI゜
_(hhh) /ΣI゜_(hkl) ] Here, I _(hkl) I゜_(hkl) is the diffraction intensity from the (hkl) plane of the oriented sample and the non-oriented sample, and Σ is the diffraction intensity of the oriented sample and the non-oriented sample. Shows the total. There are few types of elements that dissolve in Al at concentrations of several at% or more, only Li, Cu, Ag, Mg, Zn, Ga, Ge, and Si. The inventors added these elements to Al to create a solid solution, made these metal alloys into thin ribbons, irradiated the surface of the ribbon with X-rays, and examined the X-ray diffraction intensity from each (hkl) plane. Ta. An example of the results is shown in the first
As shown in the figure. In the figure, the horizontal axis shows the name of the element added to Al and the amount added in atomic % below the name, and the vertical axis shows the degree of orientation Q ₍₁₁₁₎ of the (111) plane (%). The right end of the horizontal axis shows the Q ₍₁₁₁₎ value of Al itself. As you can see from this figure, Mg is 10at%
It was found that when Al ₉₀ Mg ₁₀ is added, the alloy ribbon exhibits significant crystal orientation. The inventors,
Next, the amount of Mg added to Al is between 0 and 19 at%, and solid solutions of 0.05, 0.1, 1, 3, 5, 10, 15, and 18.9 at% of Mg, which is a solid solution of Mg, are added. Similarly, as a result of measuring Q ₍₁₁₁₎ using a metal ribbon, it was found that the Q ₍₁₁₁₎ tended to be slightly higher in the Mg-rich region, but even with 0.1 at% Mg, the degree of orientation was more than 90%. It turns out that Q ₍₁₁₁₎ can be obtained. However, for those containing 0.05 at% Mg, only the same degree of orientation as Al was observed. Therefore, the present inventors believe that in a diaphragm whose main component is Al, it is important to include 0.1 to 18.9 at% Mg as one component of the (111) plane or (211) plane of the diaphragm.
We also discovered that the (110) plane is a crystal plane with excellent acoustic properties. In the present invention, it has been found that there is no problem even if third elements such as Mn, Zn, Cu, etc. are added to the Al-Mg alloy in order to further improve its properties. In other words, some elements may lower Q ₍₁₁₁₎ slightly, but if the amount added is within a few at%, Q ₍₁₁₁₎ will be 90.
% or more, and it was confirmed that the advantages of crystal orientation were not impaired. The present inventors have determined that the crystal planes/crystal orientations are (111), (211), (110) as a texture by rolling, heat treatment, etc. for materials with (111), (211), and (110) orientation planes. ) The results of measuring the elastic modulus for those with an in-plane orientation of <111>, <110>, <211>, and those with other intermediate orientations are <111>, <110>, <211> Those with a texture with an orientation of 10 ~
It showed a 20% higher value. Therefore, the present inventors have determined that the texture of the diaphragm is (111) <110>, (111) <211>, (211) <110, including the combination of crystal planes and orientations.
>, (211) <111>, (110) <110>, (110) <111
＞, (110) <211> were both crystal orientation combinations that had excellent acoustic properties. The present inventors investigated a method for industrially manufacturing this crystal-oriented Al-Mg alloy ribbon, and found that
A comparison was made between a conventional processing method, in which a master alloy ingot is billetized, and the billet is subjected to repeated rolling and heat treatment steps to a thickness of 10 μm, and that obtained by an ultra-quenching method. As a result, in terms of mass production and cost, the ratio between the former and the latter is approximately 10:1. Furthermore, when comparing the properties of the obtained metal ribbons, such as crystal orientation, density, and elastic modulus, the former has a maximum of 70 to 80% for Q ₍₁₁₁₎ , while the latter has a maximum of 70 to 80%. 95-100 for samples obtained by ultra-quenching method
%, which is close to perfect orientation. The reason for this difference is that in the process of rolling into a thin ribbon, crystal orientation is achieved by crystal slippage, whereas in the latter, crystal growth occurs along the <111> direction during the solidification process from a metallic liquid, and this <111> direction is the main component
This is because it matches the preferred crystal growth direction of Al.
It is presumed that this difference in the mechanism of crystal orientation appears as a difference in the value of Q ₍₁₁₁₎ . In addition, it was newly discovered that samples prepared by the latter method have a significantly high tensile modulus.
These results are shown in Table 2.

[Table] Based on this, the present inventors sprayed a molten Al-Mg alloy onto the circumferential surface of a rotating metallic roller or the surface gap between a pair of metallic rollers rotating in opposite directions, and It has been found that rapid cooling to form a thin ribbon is a useful manufacturing method for industrialization. Next, specific examples of the present invention will be shown. Specific example: 99.9% purity granular Al242.8g, same purity
24.3 g of 99.9% Mg ingot was placed in an alumina crucible, melted by high-frequency induction heating in an atmosphere replaced with reduced pressure argon gas, and cast into an iron mold to form a master alloy. This master alloy was cut into small pieces of 8 mm x 8 mm x 30 mm, which were placed in a quartz tube with a 0.5 mm x 8 mm slit-shaped hole at one end, and after replacing the inside of the quartz tube with an argon gas atmosphere, the temperature was increased to 850°C. 900℃
heated to. Next, a copper roller with a diameter of 300 mm is rotated at 1600 rpm, and the aforementioned molten Al-Mg alloy is spouted out onto its circumferential surface by rapidly introducing argon gas under pressure from the other end of the quartz tube, and is ultra-quenched. It became thin. The obtained Al-Mg ribbon has a thickness of 40 μm and a width of 8
mm, and the length was 5 to 10 m. As a result of measuring the crystal orientation of this metal ribbon on the roller surface side and the opposite free surface side, Q ₍₁₁₁₎ (roller surface) = 98.5%, Q ₍₁₁₁₎ (free surface) = 93.5%. Ta. Next, cut this metal ribbon to an appropriate length,
As a result of measuring the density and elastic modulus using the dynamic elastic modulus measurement method, the density was 2510 (Kg/m ³ ) and the elastic modulus was 1.19×10 ¹⁰
(N/m ² ), and the speed of sound is calculated from this value to be 6800.
(m/s).

[Brief explanation of the drawing]

The figure shows the elements added to Al and their addition amounts (at
%) is plotted on the horizontal axis, and the vertical axis plots the degree of crystal orientation Q ₍₁₁₁₎ of the (111) plane of the added thin alloy.

Claims (1)

[Claims] 1. In an Al alloy diaphragm containing Al as a main component,
An oriented aluminum alloy diaphragm containing 0.1 to 18.9 at% Mg as at least one component thereof, and having crystal orientation in a (111) plane, a (211) plane, or a (110) plane. 2 In an Al alloy diaphragm whose main component is Al,
At least one component thereof contains 0.1 to 18.9 at% Mg, and the texture has a combination of crystal plane orientations (111) <110>, (111) <211>, (211) <110>,
(211) <111>, (110) <110>, (110) <111>,
(110) An oriented aluminum alloy diaphragm characterized by selecting one of <211>. 3 0.1 to 18.9at% Mg as at least one component
An orientation characterized by spraying a molten aluminum alloy containing aluminum onto the circumferential surface of a rotating metal roller or onto the surface gap between a pair of metal rollers rotating in opposite directions, and ultra-quenching it into a thin ribbon. aluminum alloy diaphragm.