JPH03223436A - Aluminum alloy high damping material and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture an Al alloy high damping material excellent in vibration damping capacity by forming an intergranular corrosive layer on the surface of an Al alloy contg. each specified ratio of Mg, Mn, Cu, Cr or the like into a specified depth. CONSTITUTION:An Al alloy material contg., by weight, 2 to 11% Mg, furthermore contg. one or more kinds among 0.01 to 2.5% Mn, 0.01 to 1% Cu, 0.01 to 2.0% Cr, 0.01 to 0.4% Zr, 0.005 to 1.0% Ti, 0.001 to 0.1% B, 0.05 to 3% Ni and 0.01 to 2% V and the balance Al with inevitable impurities is subjected to soln. treatment. Next, this Al alloy material is heated in the temp. range of 100 to 250 deg.C for >=1hr to precipitate beta phase precipitates in the grain boundaries and is thereafter subjected to intergranular corrosion treatment so as to form a corrosive layer into a depth of >=20mu from the surface. In this way, the Al alloy high damping material light in weight and excellent in cold workability as well as vibration damping capacity can be obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has excellent vibration damping properties and is suitable for use in audio equipment, precision equipment,
The present invention relates to an aluminum alloy vibration damping material used as a structural member that resists vibrations such as those caused by automobiles.

BACKGROUND TECHNOLOGY Generally, when an object is vibrated, the amplitude increases (becomes) at a certain frequency (fr), as shown in FIG.

This frequency is called the resonant frequency. If the amplitude at the resonant frequency is AO, the frequency that is 1/2 of this energy is the amplitude Ao/E (3 dB in dB). If this frequency width (half width, 3 dB value width) is Δf, the loss coefficient η is expressed by the following equation.

η=△f l f r A material with a large value of this loss coefficient η has excellent vibration damping properties, and vibrations are rapidly damped when external force is removed. The loss coefficient η of ordinary metal materials is 0.0 (less than II).

Conventionally, Fe-Cr has been used as a so-called vibration damping material, a metal material for structural members that dislike vibrations such as audio equipment, precision equipment, and automobiles.
Alloys such as Mrl-based, Mrl-Cu based, ZnAl based, and Ni-Ti based are known. Furthermore, Mg and Mg-Zr based cast materials are also known as vibration damping materials.

[Problem to be solved by the invention]

Fe-Cr type, Mn-Cu type, Zn-Al type.

Alloys such as the N i -T i system have common drawbacks of high vibration damping properties or high specific gravity, making them unsuitable when attempting to reduce the weight of equipment. On the other hand, Mg, M
G-Zr cast materials also have the advantage of exhibiting high vibration damping properties and low specific gravity, but have the disadvantage that they cannot be cold worked at all.

[Means to solve the problem]

In view of this, as a result of various studies, the present invention has developed an aluminum alloy vibration damping material that has a low specific gravity and is easy to cold work, and a method for manufacturing the same.

That is, one of the vibration damping materials of the present invention contains Mg2-11W1% (hereinafter W (% is abbreviated as %)), and further contains Mn0.01-2.
5%, Cu 0.01-1%, Cr0.01-20
%, Z r0.01-0.4%, T i 0.005
~1.0%, B 0.0001~0.1%, Ni0.0
Any one or two within the range of 5-3%, 7001-2%
The present invention is characterized in that an intergranular corrosion layer having a depth of at least 20 μm or more from the surface is formed on an aluminum alloy consisting of at least 100% Al species and the remainder Al and unavoidable impurities.

Another vibration damping material of the present invention contains 2 to 11% Mg, further 0.01 to 2.5% Mn, and 0.01 to 1% Cu.
, Cr 0. O1-2.0%, Z r0.01-0.4
%, Ti0.005-10%, 80.0001-01%
, Ni005-3%, V0.01-2%, and the remainder is Al and inevitable impurities.
The present invention is characterized by forming an intergranular corrosion layer with a depth of .mu.m or more, and impregnating this with a resin to form a resin-impregnated intergranular corrosion layer with a depth of at least 20 .mu.m or more from the surface.

Further, one of the production methods of the present invention includes Mg2 to 11%,
Furthermore, MnQ, QI ~2.5%, Cu0.01~1
%, Cr0.01-2.0%, Z r 0. O1~0.
4%, Ti 0.005-10%, B 0.0001-0
．． After solution treatment of an aluminum alloy containing one or more of the following in a box of 1% Ni0.005-3%, V0.01-2%, and the remainder consisting of Al and inevitable impurities,
It is characterized by heating at 100 to 250°C for 1 hour or more to precipitate β-phase precipitates at grain boundaries, which are then subjected to corrosion treatment to form an intergranular corrosion layer with a depth of at least 20 μm or more from the surface. It is something to do.

Furthermore, another manufacturing method of the present invention contains 2 to 11% Mg, further 0.01 to 2.5% Mn, and 0.01 to 1% Cu.
, Cry, old ~20%, Z r 0. O1~0.4%,
Ti 0.005-10%, B 0.0001-01%,
After solution-treating an aluminum alloy containing one or more of N1005 to 3% and V0.01 to 2%, with the remainder being Al and inevitable impurities,
Beta-phase precipitates are precipitated at grain boundaries by heating at ~250°C for 1 hour or more, and this is corroded to form an intergranular corrosion layer with a depth of at least 20 μm from the surface. The corrosion layer is characterized by being subjected to resin impregnation treatment to form an intergranular corrosion layer impregnated with resin to a depth of at least 20 μm from the surface.

[For production]

Vibration damping materials are classified into dislocation type, composite phase type, ferromagnetic type, and twin type depending on their vibration damping mechanism. The vibration damping material of the present invention differs from the above-mentioned mechanism in that it absorbs vibration energy through the minute friction between the crystal grains of the intergranular corrosion layer formed on the surface, and absorbs the vibration immediately, or the vibration is formed on the surface. The intergranular corrosion layer is impregnated with resin,
Vibration energy is absorbed by the viscoelastic deformation of the resin that fills the microscopic voids in the grain boundaries, and the vibrations are quickly absorbed.

As a means to preferentially corrode the grain boundaries, either by precipitating an intermetallic compound whose potential is less noble and which is more likely to corrode the grain boundaries, or by making the vicinity of the grain boundaries less noble than the inside of the grains,
Corrosion treatment is effective.

The reasons for limiting the alloy composition range in the present invention as described above will be described below.

The reason for limiting the Mg content to 2 to 11% is that Mg is in the β phase (
i-Mg-based intermetallic compound) is preferentially precipitated at grain boundaries,
It is added to preferentially dissolve the beta phase, which has a less common potential, during corrosion treatment, and if it is less than 2%, precipitation of the beta phase will not occur.
This is because if it exceeds 11%, a large amount of β phase precipitates not only at the grain boundaries but also inside the grains, making it difficult to preferentially corrode the grain boundaries.

Mn is 0.01 to 2.5% as other contained elements.

Cu 0.01-1%, Cr0.01-2.0%, Zr
0.01~04%, Ti0.005~1.0%, B
0. (1001-0.1%, Ni 0.05-3%,
Limiting the amount of one or more types within the range of V0.01 to 2% improves the strength of the material, but if it is less than the lower limit, the effect is not sufficient, and if it exceeds the upper limit, it will become coarse. This is because there is a possibility that compounds may be formed and the ductility of the material may be inhibited.

In addition, as other impurities, Si and Fe each have a content of 0.5%.
Below, other impurities do not particularly impair the effects of the present invention as long as they are 0.1% or less. In addition, for the purpose of improving castability, Be
It is also possible to add 500 ppm or less.

Next, in the production method of the present invention, containing 2 to 11% of Mg,
Furthermore, Mn0.01-2.5%, Cu 0.01-1
%, Cr0.01-2.0%, Zr0. O1~0.
4%, Ti0.005-1.0%, B 0.0001
~0.1%, Ni0105~3%, V0.01~2%
Contains one or more of the following, with the remainder being Al.
Heating aluminum alloys containing unavoidable impurities, such as rolled materials, plates, extruded materials, pipes, cast products, castings, etc. at 100 to 250°C for more than 1 hour after solution treatment, mainly causes damage to the grain boundaries. This is to precipitate β-phase precipitates, and if the heating temperature is less than 100°C or higher than 250°C and the holding time is less than 1 hour, the β-phase cannot be sufficiently precipitated at grain boundaries. The most suitable condition is 110~
It is to hold at 180°C for 2 hours or more. It is appropriate to perform the solution treatment at 400 to 550°C for 1 hour or more, and once Mg is uniformly dissolved in solid solution, the β phase is uniformly precipitated at the grain boundaries in the subsequent precipitation treatment. Even if the processing conditions are slightly different, the effects of the present invention will not be significantly impaired.

The aluminum aluminum alloy subjected to grain boundary precipitation treatment in this manner is then subjected to grain boundary corrosion treatment so that the corrosion layer is 20 μm or more from the surface.

Intergranular corrosion treatment is carried out by immersion in salts such as NaCl, acids such as HF HCI, alkaline aqueous solutions such as NaOH, or mixed solutions of these, or by electrolysis by applying an anode current. In either case, the corrosion layer may be formed to a depth of 20 μm or more.

Aluminum alloys subjected to such intergranular corrosion treatment are
Although it exhibits excellent vibration damping properties as it is, when the intergranular corrosion layer is further impregnated with resin, the vibration damping properties are dramatically improved. Examples of resins to be impregnated include alkyd resin, nitrocellulose resin, butyral resin, polyurethane resin, polypropylene resin, polyethylene resin, Evoquin resin,
Amino alkyd resin, acrylic resin.

Polyester resin, vinyl acetate resin, vinyl chloride resin,
Silicone resins, mixed resins of these resins, and modified versions of these resins are all suitable for use, but among these, polyester resins, polypropylene resins, silicone resins, etc., which have particularly high viscoelasticity, have the highest vibration damping properties. shows.

These resins can be spray painted, electrostatically painted, TFS painted,
It is impregnated into an aluminum alloy that has been subjected to intergranular corrosion treatment by methods such as dipping and powder coating. At this time, it is desirable to impregnate at least the intergranular corrosion layer until it is completely filled with soil.

Generally, during vibration, the amplitude is maximum at the surface of an object, so it is effective to apply intergranular corrosion and resin impregnation to the surface layer, but if the depth is less than 20 μm, the vibration damping property is insufficient, and vibration damping materials In order to use the material as a material, it is necessary to form an intergranular corrosion layer with a depth of 20 μm or more or a resin-impregnated intergranular corrosion layer.

Although the aluminum alloy vibration damping material of the present invention can be cold-worked, the effects of the present invention will not be impaired even if cold-worked as necessary before intergranular corrosion treatment or resin impregnation treatment. do not have.

〔Example〕

The present invention will be described below with reference to Examples.

Example 1 An aluminum alloy ingot having the composition shown in Table 1 was hot-rolled and cold-rolled into a plate material with a grinding thickness of 2 mm. Next 491
1"C: After solution treatment for 8 hours at 150°C, grain boundary precipitation treatment was performed at 150°C for 12 hours, followed by 3% Na (1 + 1% HC).
/ immersed in an aqueous solution (50°C) to form intergranular corrosion layers of various depths. From this thickness 2mm, width 10M, length 2
A 50 mm test piece was cut out, and its vibration damping property (loss coefficient η) was evaluated by the cantilever beam vibration method.

In other words, one end of the test piece is chucked and the oscillator is used to force it: ・A dam vibration is applied, the resulting vibration of the test piece is detected, and the input vibration and detected (output) vibration are subjected to two-channel fast Fourier transform. Find the input/output amplitude ratio (frequency response function) in the frequency domain using a 2ch FFT, and find the resonance frequency (fr) that shows the maximum amplitude ratio and the frequency width (△f) that is 3 dB lower than the maximum amplitude ratio. The loss coefficient η was determined using the following equation.

η=△f/f r The depth of the intergranular corrosion layer was measured by polishing the cross section of the test piece and using an optical microscope.

As is clear from Table 1, Examples Nα1 to Nα5 of the present invention exhibit high loss coefficients η of 0.012 or more.

On the other hand, in comparison levels 6 to 7, where the alloy composition deviates from that of the vibration damping material of the present invention, grain boundaries cannot be preferentially corroded even if corrosion treatment is performed, resulting in a full-scale dissolution type of corrosion, resulting in loss coefficient η shows a low value. Furthermore, it can be seen that even with the alloy composition of the vibration damping material of the present invention, the loss coefficient η is low in Comparative Example Nα8 in which the intergranular corrosion layer is 20 μm or less.

Example 2 An aluminum alloy ingot having a composition of Nα2 in Table 1 was hot rolled into a plate with a thickness of 3 mm, solution treated at 490°C for 8 hours, and then subjected to precipitation treatment under various conditions shown in Table 2. The samples were subjected to the same intergranular corrosion treatment as in Example 1, and the intergranular corrosion layer of some of the samples was impregnated with polyethylene resin. The loss coefficient η of these samples was measured in the same manner as in Example 1. The results are also listed in Table 2.

Table 2 As is clear from Table 2, the layers '9 to 11 of the present invention, which were subjected to precipitation treatment by the production method of the present invention to form a grain boundary corrosion layer of 20 μm or more, exhibited a high loss coefficient η, and Those impregnated with have a particularly high loss factor.

On the other hand, Comparative Examples Nα12 to Nα14, which were subjected to precipitation treatment that differed from the production method of the present invention, were unable to cause intergranular corrosion.
It can be seen that the loss coefficient η is also a low value.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain an aluminum alloy vibration damping material that is lightweight because it is based on aluminum, has excellent cold workability, and has excellent vibration damping properties, and is an industrially outstanding material. It is effective.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a vibration resonance curve of an object. fr, resonant frequency AO: amplitude at resonant frequency △f: frequency width

Claims (4)

[Claims] (1) Contains Mg2~11wt%, and further includes Mn0.01~
2.5wt%, Cu0.01-1wt%, Cr0.01
~2.0wt%, Zr0.01~0.4wt%, Ti0
．． 005-1.0wt%, B0.0001-0.1wt
%, Ni 0.05 to 3 wt%, V 0.01 to 2 wt%, and the remainder is Al and inevitable impurities, to a depth of at least 20 μm from the surface. An aluminum alloy vibration damping material characterized by forming an intergranular corrosion layer. (2) Contains Mg2 to 11 wt%, and further includes Mn0.01 to
2.5wt%, Cu0.01-1wt%, Cr0.01
~2.0wt%, Zr0.01~0.4wt%, Ti0
．． 005-1.0wt%, B0.0001-0.1wt
%, Ni 0.05 to 3 wt%, V 0.01 to 2 wt%, and the remainder is Al and inevitable impurities, to a depth of at least 20 μm from the surface. 1. An aluminum alloy vibration damping material, characterized in that the intergranular corrosion layer is impregnated with a resin to form a intergranular corrosion layer at a depth of at least 20 μm from the surface. (3) Contains Mg2 to 11 wt%, and further includes Mn0.01 to
2.5wt%, Cu0.01-1wt%, Cr0.01
~2.0wt%, Zr0.01~0.4wt%, Ti0
．． 005-1.0wt%, B0.0001-0.1wt
%, Ni 0.05 to 3 wt%, V 0.01 to 2 wt%, and the remainder is Al and unavoidable impurities. Aluminum that is heated at 250°C for 1 hour or more to precipitate β-phase precipitates at grain boundaries, and then undergoes corrosion treatment to form an intergranular corrosion layer with a depth of at least 20 μm from the surface. Method for manufacturing alloy vibration damping material. (4) Contains Mg2~11wt%, and further includes Mn0.01~
2.5wt%, Cu0.01-1wt%, Cr0.01
~2.0wt%, Zr0.01~0.4wt%, Ti0
．． 005-1.0wt%, B0.0001-0.1wt
%, Ni 0.05 to 3 wt%, V 0.01 to 2 wt%, and the remainder is Al and unavoidable impurities. Heating at 250° C. for 1 hour or more to precipitate β phase at grain boundaries, and corroding this to form an intergranular corrosion layer with a depth of at least 20 μm from the surface,
A method for producing an aluminum alloy vibration damping material, characterized in that the intergranular corrosion layer is then impregnated with a resin to form a resin-impregnated intergranular corrosion layer at a depth of at least 20 μm from the surface.